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Go (board game)
Encyclopedia
Go is an ancient board game
for two players that originated in China
more than 2,000 years ago. The game is noted for being rich in strategy despite its relatively simple rules.
The game is played by two players who alternately place black and white stones on the vacant intersections (called "points") of a grid of 19×19 lines (beginners often play on smaller 9×9 and 13×13 boards). The object of the game is to use one's stones to surround a larger portion of the board than the opponent. Once placed on the board, stones cannot be moved, though they can be removed if they are captured. When a game concludes, the controlled points (territory) are counted along with captured stones to determine who has more points. Games may also be won by resignation.
Placing stones close together usually helps them support each other and avoid capture, while placing stones far apart creates influence across more of the board. Part of the strategic difficulty of the game stems from finding a balance between these types of conflicting interests. Players strive to serve both defensive and offensive purposes and choose between tactical urgency and strategic plans. At its basis, the game is one of simple logic, while in advanced play the game involves complex heuristic
s and tactical analysis. Beginning players first learn the simple mechanics of how stones interact, while intermediate students learn concepts such as initiative ("sente"), influence, and the proper timing of moves.
Go originated in ancient China; exactly when is unknown. By the 3rd century BC it was already a popular pastime, as indicated by a reference to the game in the Analects of Confucius
. Archaeological evidence shows that the early game was played on a board with a 17×17 grid, but by the time the game had spread to Korea
and Japan
, in about the 5th and 7th centuries respectively, boards with a 19×19 grid had become standard.
The game is most popular in East Asia. A survey done in 2003 places the number of Go players worldwide at approximately 27 million. Go reached the West through Japan, which is why it is commonly known internationally by its shortened Japanese name, and why terms for common Go concepts
are commonly derived from its Japanese pronunciation. The full Japanese name igo is derived from its Chinese name weiqi, which roughly translates as "board game of surrounding."The full Japanese name igo is derived from its Chinese name weiqi, which roughly translates as "board game of surrounding", see Etymology Of Go at Sensei's Library for more information. To differentiate the game Go from the common English verb to go
, it is generally capitalized (Gao 2007) or, in events sponsored by the Ing
Foundation, spelled goe.
The basic principle of Go is that stones must have "liberty" to remain on the board. A liberty is an open point (intersection) next to a stone. An enclosed liberty is called an "eye," and a group of stones with at least two eyes is said to be unconditionally alive. Such groups cannot be captured. Dead stones are those which are surrounded and have poor shape (one or no eyes) and thus cannot resist eventual capture.
The general strategy of Go is to expand one's territory where possible, attack the opponent's weak groups (groups which can possibly be killed), and always stay mindful of the "life status
" of one's own groups.
The liberties of groups are countable and it is often important to keep track of their number. In cases where two opposing groups must capture the other to live, these "capturing races" ("semeai") all ultimately reduce to a logical and concrete contest of relative liberties —the group with the more liberties (and/or "better shape") will capture the opponent stones and thus live. Semeais and life and death problems are examples of where parts of the game can form a type of puzzle
. Solving the puzzle means accurately observing and understanding the situation and making the appropriate move. For example one may have to make a move to save one of their own groups, or one may have an opportunity to kill an opponent's group and thus capture some stones and territory.
The game's opening stages largely deal with establishing "bases" (or 'footholds') around the sides of the board. These bases help to quickly establish living shapes. There are special properties associated with the corners as well, which are studied in corner opening sequences ("joseki
") and in many life and death problems. The first principle of opening theory is to play in the corners, because it is more efficient there to make life and to establish territory. The game ends when both players pass. Players pass when there are no more profitable moves to be made —when playing within one's own territory removes points from one's score, and when playing within the opponent's territory will be fruitless.
"Dame" are points that lie in-between the boundary walls of Black and White, and as such are considered to be of no value to either side. "Sekis" are mutually alive groups without two eyes. A "ko" is a repeated-position shape which may be contested by making forcing moves elsewhere. After the forcing move is played, the ko may be "taken back" and returned to its original position. Some "ko fights" may be important and decide the life of a large group, while others may simply be worth one or two points. There are different rule-sets (Japanese, Chinese, AGA, etc.) which end up being almost entirely equivalent except for certain special-case positions.
for which there is no ready English equivalent are commonly called by their Japanese names.
Two players, Black and White, take turns placing a stone (game piece) of their own color on a vacant point (intersection) of the grid on a Go board. Black moves first. If there is a large difference in skill between the players, Black will typically be allowed to place two or more stones on the board to compensate for the difference (see Go handicaps). The official grid comprises 19×19 lines, though the rules can be applied to any grid size. 13×13 and 9×9 boards are popular choices to teach beginners. Once placed, a stone may not be moved to a different point.
Vertically and horizontally adjacent stones of the same color form a chain (also called a string, or simply a group) that shares its liberties (see below) in common, cannot subsequently be subdivided, and in effect becomes a single larger stone. Only stones connected to one another by the lines on the board create a chain; stones that are diagonally adjacent are not connected. Chains may be expanded by placing additional stones on adjacent intersections, and can be connected together by placing a stone on an intersection that is adjacent to two or more chains of the same color.
A vacant point adjacent to a stone is called a liberty for that stone.Compare "liberty
", a small local government unit in medieval England – the "local area under control". Stones in a chain share their liberties. A chain of stones must have at least one liberty to remain on the board. When a chain is surrounded by opposing stones so that it has no liberties, it is captured and removed from the board.
While the various rule sets agree on the ko rule prohibiting returning the board to an immediately previous position, they deal in different ways with the relatively uncommon situation in which a player might recreate a past position that is further removed. See Rules of Go: Repetition for further information.
The Chinese rules allow an exception to this rule, such that a player might destroy one of its own groups--"commit suicide." This play would only be useful in a limited set of situations involving a small interior space.
, the idea of awarding White some compensation came into being during the 20th century. This predetermined compensation, called "komidashi
," ("komi") means that for even games white may receive somewhere on average of 6.5 points compensation for Black's first move advantage. If there is one stone difference in strength between players, the stronger player takes White, and White may receive only .5 points komi, just to break a possible tie ("jigo"). In handicap games with 2 or more handicap stones, White may also take .5 points komi to break a tie.
in the 15th or 16th century.
Area scoring (including Chinese): A player's score is the number of stones he has on the board, plus the number of empty intersections surrounded by that player's stones.
Territory scoring (including Japanese and Korean): In the course of the game, each player retains the stones they capture, termed prisoners. Any dead stones removed at the end of the game become prisoners. The score is the number of empty points enclosed by a player's stones, plus the number of prisoners captured by that player.Exceptionally, in Japanese and Korean rules, empty points, even those surrounded by stones of a single colour, may count as neutral territory if some of them are alive by seki. See the section on "Life and Death" for seki.
If there is disagreement about which stones are dead, then under area scoring rules, the players simply resume play to resolve the matter. The score is computed using the position after the next time the players pass consecutively. Under territory scoring, the rules are considerably more complex; however, in practice, players will generally play on, and, once the status of each stone has been determined, return to the position at the time the first two consecutive passes occurred and remove the dead stones. For further information, see Rules of Go
.
Given that the number of stones a player has on the board is related to the number of prisoners the opponent has taken, the resulting net score (the difference between Black and White's respective scores) under both rulesets is often identical and rarely differs by more than a point.
When a group of stones is mostly surrounded and has no options to connect with friendly stones elsewhere, the status of the group is either alive, dead or unsettled. A group of stones is said to be alive if it cannot be captured, even if the opponent is allowed to move first. Conversely, a group of stones is said to be dead if it cannot avoid capture, even if the owner of the group is allowed the first move. Otherwise, the group is said to be unsettled: in such a situation, the player that moves first may be able to either make it alive if he is the owner, or kill it if he is the group owner's opponent.
To be alive, a group must be able to create at least two "eyes" if threatened. An eye is an empty point that is surrounded by friendly stones, where the opponent can never play due to the suicide rule. If two such eyes exist, the opponent can never capture a group of stones, because it will always have at least two liberties. One eye is not enough for life, because a point that would normally be suicide may be played upon if doing so fills the last liberty of opposing stones, thereby capturing those stones. In the "Examples of eyes" diagram, all the circled points are eyes. The two black groups in the upper corners are alive, as both have at least two eyes. The groups in the lower corners are dead, as both have only one eye. The group in the lower left may seem to have two eyes, but the surrounded empty point without a circle is not actually an eye. White can play there and take a black stone. Such a point is often called a false eye.
.
Sekis can occur in many ways. The simplest are: (1) each player has a group without eyes and they share two liberties, and (2) each player has a group with one eye and they share one more liberty. In the "Example of seki (mutual life)" diagram, the circled points are liberties shared by both a black and a white group. Neither player wants to play on a circled point, because doing so would allow the opponent to capture. All the other groups in this example, both black and white, are alive with at least two eyes. Sekis are unusual, but can result from an attempt by one player to invade and kill a nearly settled group of the other player.
The most basic technique is the ladder. To capture stones in a ladder, a player uses a constant series of capture threats—called atari—to force the opponent into a zigzag pattern as shown in the diagram to the right. Unless the pattern runs into friendly stones along the way, the stones in the ladder cannot avoid capture. Experienced players will recognize the futility of continuing the pattern and will play elsewhere. The presence of a ladder on the board does give a player the option to play a stone in the path of the ladder, thereby threatening to rescue their stones, forcing a response. Such a move is called a ladder breaker and may be a powerful strategic move. In the diagram, Black has the option of playing a ladder breaker.
Another technique to capture stones is the so-called net, also known by its Japanese name, geta. This refers to a move that loosely surrounds some stones, preventing their escape in all directions. An example is given in the diagram to the left. It is generally better to capture stones in a net than in a ladder, because a net does not depend on the condition that there are no opposing stones in the way, nor does it allow the opponent to play a strategic ladder breaker.
A third technique to capture stones is the snapback. In a snapback, one player allows a single stone to be captured, then immediately plays on the point formerly occupied by that stone; by so doing, the player captures a larger group of their opponent's stones, in effect snapping back at those stones. An example can be seen on the right. As with the ladder, an experienced player will not play out such a sequence, recognizing the futility of capturing only to be captured back immediately.
As explained in the scoring rules, some stone formations can never be captured and are said to be alive, while other stones may be in the position where they cannot avoid being captured and are said to be dead. Much of the practice material available to students of the game comes in the form of life and death problems, also known as tsumego
. In such problems, players are challenged to find the vital move sequence that will kill a group of the opponent or save a group of their own. Tsumego are considered an excellent way to train a player's ability at reading ahead, and are available for all skill levels, some posing a challenge even to top players.
Instead of responding to a ko threat, a player may also choose to ignore the threat and connect the ko. They thereby win the ko, but at a cost. The choice of when to respond to a threat and when to ignore it is a subtle one, which requires a player to consider many factors, including how much is gained by connecting, how much is lost by not responding, how many possible ko threats both players have remaining, what the optimal order of playing them is, and what the size—points lost or gained—of each of the remaining threats is.
Frequently, the winner of the ko fight does not connect the ko but instead captures one of the chains that constituted their opponent's side of the ko. In some cases, this leads to another ko fight at a neighboring location.
Go is not easy to play well. With each new level (rank) comes a deeper appreciation for the subtlety and nuances involved and for the insight of stronger players. The acquisition of major concepts of the game comes slowly. Novices often start by randomly placing stones on the board, as if it were a game of chance; they inevitably lose to experienced players who know how to create effective formations. An understanding of how stones connect for greater power develops, and then a few basic common opening sequences
may be understood. Learning the ways of life and death helps in a fundamental way to develop one's strategic understanding of weak groups. It is necessary to play thousands of games before one can get close to one's ultimate potential skill level in Go. A player who both plays aggressively and can handle adversity is said to display kiai
, or fighting spirit, in the game.
Familiarity with the board shows first the tactical importance of the edges, and then the efficiency of developing in the corners first, then sides, then center. The more advanced beginner understands that territory and influence are somewhat interchangeable—but there needs to be a balance. This intricate struggle of power and control makes the game highly dynamic.
The strategy involved can become very abstract and complex. High-level players spend years improving their understanding of strategy, and a novice may play many hundreds of games against opponents before being able to win regularly.
In the opening, players often play established sequences called joseki
, which are locally balanced exchanges; however, the joseki chosen should also produce a satisfactory result on a global scale. It is generally advisable to keep a balance between territory and influence. Which of these gets precedence is often a matter of individual taste.
The end of the middlegame and transition to the endgame is marked by a few features. The game breaks up into areas that do not affect each other (with a caveat about ko fights), where before the central area of the board related to all parts of it. No large weak groups are still in serious danger. Moves can reasonably be attributed some definite value, such as 20 points or fewer, rather than simply being necessary to compete. Both players set limited objectives in their plans, in making or destroying territory, capturing or saving stones. These changing aspects of the game usually occur at much the same time, for strong players. In brief, the middlegame switches into the endgame when the concepts of strategy and influence need reassessment in terms of concrete final results on the board.
(c. 4th century BC), referring to a historical event of 548 BC. It is also mentioned in Book XVII of the Analects of Confucius
and in two books written by Mencius
(c. 3rd century BC). In all of these works, the game is referred to as . Today, in China, it is known as weiqi , literally the "encirclement board game".
Go was originally played on a 17×17 line grid, but a 19×19 grid became standard by the time of the Tang Dynasty
(618–907). Legends trace the origin of the game to Chinese emperor
Yao (2337–2258 BC), said to have had his counselor Shun design it for his unruly son, Danzhu, to favorably influence him. Other theories suggest that the game was derived from Chinese tribal warlords and generals, who used pieces of stone to map out attacking positions.
In China, Go was considered one of the four cultivated arts
of the Chinese scholar gentleman
, along with calligraphy, painting
and playing the musical instrument guqin
.
: ), and a variant of the game called Sunjang baduk
was developed by the 16th century. Sunjang baduk became the main variant played in Korea until the end of the 19th century.
The game reached Japan in the 7th century AD —where it is called or —the game became popular at the Japanese imperial court in the 8th century, and among the general public by the 13th century. In 1603, Tokugawa Ieyasu
re-established Japan's unified national government. In the same year, he assigned the then-best player in Japan, a Buddhist monk named Nikkai (né Kanō Yosaburo, 1559), to the post of Godokoro
(Minister of Go). Nikkai took the name Honinbo Sansa
and founded the Honinbo Go school. Several competing schools
were founded soon after. These officially recognized and subsidized Go schools greatly developed the level of play and introduced the dan/kyu style system
of ranking players. Players from the four schools (Honinbo, Yasui, Inoue and Hayashi) competed in the annual castle games, played in the presence of the shogun
.
wrote a treatise on the game. By the early 20th century, Go had spread throughout the German
and Austro-Hungarian
empires. In 1905, Edward Lasker
learned the game while in Berlin. When he moved to New York, Lasker founded the New York Go Club together with (amongst others) Arthur Smith, who had learned of the game while touring the East and had published the book The Game of Go in 1908. Lasker's book Go and Go-moku (1934) helped spread the game throughout the US, and in 1935, the American Go Association was formed. Two years later, in 1937, the German Go Association was founded.
World War II
put a stop to most Go activity, but after the war, Go continued to spread. For most of the 20th century, the Japan Go Association
played a leading role in spreading Go outside East Asia by publishing the English-language magazine Go Review in the 1960s; establishing Go centers
in the US, Europe and South America; and often sending professional teachers on tour to Western nations.
In 1996, NASA
astronaut Daniel Barry
and Japanese astronaut Koichi Wakata
became the first people to play Go in space. Both astronauts were awarded honorary dan rank
s by the Nihon Ki-in
.
, the International Go Federation
has a total of 71 member countries. It has been claimed that across the world 1 person in every 222 plays Go.
In Go, rank indicates a player's skill in the game. Traditionally, ranks are measured using kyu and dan grades, a system which also has been adopted by many martial arts
. More recently, mathematical rating systems similar to the Elo rating system
have been introduced. Such rating systems often provide a mechanism for converting a rating to a kyu or dan grade. Kyu grades (abbreviated k) are considered student grades and decrease as playing level increases, meaning 1st kyu is the strongest available kyu grade. Dan grades (abbreviated d) are considered master grades, and increase from 1st dan to 7th dan. First dan
equals a black belt
in eastern martial arts using this system. The difference among each amateur rank is one handicap stone. For example, if a 5k plays a game with a 1k, the 5k would need a handicap of four stones to even the odds. Top-level amateur players sometimes defeat professionals in tournament play. Professional players have professional dan ranks
(abbreviated p). These ranks are separate from amateur ranks.
The rank system comprises, from the lowest to highest ranks:
), handicap strategies, and time control parameters. Rules that do not generally influence the game are: the tournament system, pairing strategies, and placement criteria.
Common tournament systems used in Go include the McMahon system, Swiss system
, league system
s and the knockout system
. Tournaments may combine multiple systems; many professional Go tournaments use a combination of the league and knockout systems.
Tournament rules may also set the following:
by Tokugawa Ieyasu
at the start of the 17th century shifted the focus of the Go world to Japan. State sponsorship, allowing players to dedicate themselves full time to study of the game, and fierce competition between individual houses resulted in a significant increase in the level of play. During this period, the best player of his generation was given the prestigious title Meijin
(master) and the post of Godokoro
(minister of Go). Of special note are the players who were dubbed Kisei
(Go Sage). The only three players to receive this honor were Dosaku, Jowa and Shusaku
, all of the house Honinbo
.
After the end of the Tokugawa shogunate
and the Meiji Restoration
period, the Go houses slowly disappeared, and in 1924, the Nihon Ki-in
(Japanese Go Association) was formed. Top players from this period often played newspaper-sponsored matches of 2–10 games. Of special note are Go Seigen
(Chinese: Wu Qingyuan), who scored an impressive 80% in these matches, and Minoru Kitani
, who dominated matches in the early 1930s. These two players are also recognized for their groundbreaking work on new opening theory
(Shinfuseki
).
For much of the 20th century, Go continued to be dominated by players trained in Japan. Notable names included Eio Sakata
, Rin Kaiho
(born in China), Masao Kato
, Koichi Kobayashi
and Cho Chikun
(born Cho Ch'i-hun, South Korea). Top Chinese and Korean talents often moved to Japan, because the level of play there was high and funding was more lavish. One of the first Korean players to do so was Cho Namchul, who studied in the Kitani Dojo 1937–1944. After his return to Korea, the Hanguk Kiwon (Korea Baduk Association) was formed and caused the level of play in South Korea to rise significantly in the second half of the 20th century. In China, the game declined during the Cultural Revolution
(1966–1976) but quickly recovered in the last quarter of the 20th century, bringing Chinese players, such as Nie Weiping
and Ma Xiaochun
, on par with their Japanese and Korean counterparts.
With the advent of major international titles from 1989 onward, it became possible to compare the level of players from different countries more accurately. Korean players such as Lee Chang-ho
, Cho Hunhyun
, Lee Sedol
and Yoo Changhyuk
dominated international Go and won an impressive number of titles. Several Chinese players also rose to the top in international Go, most notably Ma Xiaochun
, Chang Hao
and Gu Li
. , Japan lags behind in the international Go scene.
Historically, as with most sports and games, more men than women have played Go. Special tournaments for women exist, but until recently, men and women did not compete together at the highest levels; however, the creation of new, open tournaments and the rise of strong female players, most notably Rui Naiwei
, have in recent years highlighted the strength and competitiveness of emerging female players.
The level in other countries has traditionally been much lower, except for some players who had preparatory professional training in Asia.Kaku Takagawa
toured Europe around 1970, and reported (Go Review) a general standard of amateur 4 dan. This is a good amateur level but no more than might be found in ordinary Asian clubs. Published current European ratings would suggest around 100 players stronger than that, with very few European 7 dans. Knowledge of the game has been scant elsewhere up until the 20th century. A famous player of the 1920s was Edward Lasker
.European Go has been documented by Franco Pratesi, Eurogo (Florence 2003) in three volumes, up to 1920, 1920–1950, and 1950 and later. It was not until the 1950s that more than a few Western players took up the game as other than a passing interest. In 1978, Manfred Wimmer
became the first Westerner to receive a professional player's certificate from an Asian professional Go association. In 2000, a Westerner, Michael Redmond, finally achieved the top rank awarded by an Asian Go association, 9 dan. In total, , only nine non-Asian Go players have ever achieved professional status in Asian associations.
It is possible to play Go with a simple paper board and coins or plastic tokens for the stones. More popular midrange equipment includes cardstock, a laminate
d particle board
, or wood boards with stones of plastic or glass. More expensive traditional materials are still used by many players. The most expensive Go sets have black stones carved from slate and white stones carved from translucent white shells.
The traditional Japanese goban is between 10 centimetre thick and has legs; it sits on the floor (see picture to right). It is preferably made from the rare golden-tinged Kaya
tree (Torreya nucifera), with the very best made from Kaya trees up to 700 years old. More recently, the related California Torreya
(Torreya californica) has been prized for its light color and pale rings as well as its reduced expense and more readily available stock. The natural resources of Japan have been unable to keep up with the enormous demand for the slow-growing Kaya trees; both T. nucifera and T. californica take many hundreds of years to grow to the necessary size, and they are now extremely rare, raising the price of such equipment tremendously. As Kaya trees are a protected species in Japan, they cannot be harvested until they have died. Thus, an old-growth, floor-standing Kaya goban can easily cost in excess of US$10,000 with the highest-quality examples costing more than $60,000.
Other, less expensive woods often used to make quality table boards in both Chinese and Japanese dimensions include Hiba
(Thujopsis dolabrata), Katsura (Cercidiphyllum japonicum), Kauri
(Agathis), and Shin Kaya (various varieties of spruce
, commonly from Alaska, Siberia and China's Yunnan Province). So-called Shin Kaya is a potentially confusing merchant's term: shin means "new", and thus shin kaya is best translated "faux kaya", because the woods so described are biologically unrelated to Kaya.
Traditional Japanese stones are double-convex, and made of clam
shell (white) and slate
(black). The classic slate is nachiguro stone mined in Wakayama Prefecture
and the clamshell from the Hamaguri clam; however, due to a scarcity in the Japanese supply of this clam, the stones are most often made of shells harvested from Mexico
. Historically, the most prized stones were made of jade
, often given to the reigning emperor as a gift.
In China, the game is traditionally played with single-convex stones made of a composite called Yunzi
. The material comes from Yunnan Province and is made by sintering
a proprietary and trade-secret mixture of mineral compounds. This process dates to the Tang Dynasty and, after the knowledge was lost in the 1920s during the Chinese Civil War
, was rediscovered in the 1960s by the now state-run Yunzi company. The material is praised for its colors, its pleasing sound as compared to glass or to synthetics such as melamine
, and its lower cost as opposed to other materials such as slate/shell. The term "yunzi" can also refer to a single-convex stone made of any material; however, most English-language Go suppliers will specify Yunzi as a material and single-convex as a shape to avoid confusion, as stones made of Yunzi are also available in double-convex while synthetic stones can be either shape.
Traditional stones are made so that black stones are slightly larger in diameter than white; this is to compensate for the optical illusion created by contrasting colors that would make equal-sized white stones appear larger on the board than black stones.See Overshoot
in Western typography for similar subtle adjustment to create a uniform appearance.
glass, such as for brandy
. The bowls are usually made of turned wood. Rosewood
is the traditional material for Japanese bowls, but is very expensive; wood from the Chinese jujube
date tree, which has a lighter color (it is often stained) and slightly more visible grain pattern, is a common substitute for rosewood, and traditional for Go Seigen-style bowls. Other traditional materials used for making Chinese bowls include lacquer
ed wood, ceramics, stone and woven straw or rattan
. The names of the bowl shapes, Go Seigen and Kitani, pay homage to two 20th-century professional Go players by the same names, of Chinese and Japanese nationality, respectively, who are referred to as the "Fathers of modern Go".
that can be rolled up. In such cases, the stones are usually made of glass, plastic or resin (such as melamine or Bakelite) rather than slate and shell. Bowls are often made of plastic or inexpensive wood.
Common "novice" Go sets are all-inclusive kits made of particle board or plywood
, with plastic or glass stones, that either fold up to enclose the stone containers or have pull-out drawers to keep stones. In relative terms, these sets are inexpensive, costing US$20–$40 depending on component quality, and thus are popular with casual Go players. Magnetic sets are also available, either as portable travel sets or in larger sizes for educational purposes.
The traditional way to place a Go stone is to first take one from the bowl, gripping it between the index and middle fingers, with the middle finger on top, and then placing it directly on the desired intersection. It is considered respectful towards one's opponent to place one's first stone in the upper right-hand corner. It is permissible to emphasize select moves by striking the board more firmly than normal, thus producing a sharp clack.
. Formal time controls were introduced into the professional game during the 1920s and were controversial. Adjournments and sealed moves began to be regulated in the 1930s. Go tournaments use a number of different time control systems. All common systems envisage a single main period of time for each player for the game, but they vary on the protocols for continuation (in overtime) after a player has finished that time allowance.Roughly, one has the time to play the game and then a little time to finish it off. Time-wasting tactics are possible in Go, so that sudden death systems, in which time runs out at a predetermined point however many plays are in the game, are relatively unpopular (in the West). The most widely used time control system is the so called byoyomi
Literally in Japanese byōyomi means 'reading of seconds'. system. The top professional Go matches have timekeepers so that the players do not have to press their own clocks.
Two widely used variants of the byoyomi system are:
, except that Go stones do not move and thus require only one coordinate per turn. Coordinate systems include purely numerical (4-4 point), hybrid (K3), and purely alphabetical. The Smart Game Format
uses alphabetical coordinates internally, but most editors represent the board with hybrid coordinates as this reduces confusion. The Japanese word kifu
is sometimes used to refer to a game record.
In combinatorial game theory
terms, Go is a zero sum, perfect-information
, partisan
, deterministic
strategy game
, putting it in the same class as chess, checkers (draughts) and Reversi
(Othello); however it differs from these in its game play. Although the rules are simple, the practical strategy is extremely complex.
The game emphasizes the importance of balance on multiple levels and has internal tensions. To secure an area of the board, it is good to play moves close together; however, to cover the largest area, one needs to spread out, perhaps leaving weaknesses that can be exploited. Playing too low (close to the edge) secures insufficient territory and influence, yet playing too high (far from the edge) allows the opponent to invade.
It has been claimed that Go is the most complex game in the world due to its vast number of variations in individual games. Its large board and lack of restrictions allow great scope in strategy and expression of players' individuality. Decisions in one part of the board may be influenced by an apparently unrelated situation in a distant part of the board. Plays made early in the game can shape the nature of conflict a hundred moves later.
The game complexity
of Go is such that describing even elementary strategy fills many introductory books. In fact, numerical estimates show that the number of possible games of Go far exceeds the number of atoms in the known universe.The number of board positions is at most 3361 (about 10172) since each position can be white, black, or vacant. Ignoring (illegal) suicide moves, there are at least 361! games (about 10768) since every permutation of the board positions corresponds to a game. See Go and mathematics
for more details, which includes much larger estimates.
without losing a single game in 2006). The best Go programs manage to reach amateur dan level. On the small 9×9 board, the computer fares better, and some programs now win a fraction of their 9×9 games against professional players. Many in the field of artificial intelligence
consider Go to require more elements that mimic human thought than chess
.
The reasons computer programs do not play Go at the professional dan level:
As an illustration, the greatest handicap normally given to a weaker opponent is 9 stones. It was not until August 2008 that a computer was able to win a game against a professional level player at this handicap. It was the Mogo program which scored said first victory in an exhibition game played during the US Go Congress.
There are several file formats used to store game records, the most popular of which is SGF, short for Smart Game Format
. Programs used for editing game records allow the user to record not only the moves, but also variations, commentary and further information on the game.Lists of such programs may be found at Sensei's Library or GoBase.
Electronic databases can be used to study life and death situations, joseki
, fuseki
and games by a particular player. Programs are available that give players pattern searching options, which allow players to research positions by searching for high-level games in which similar situations occur. Such software generally lists common follow-up moves that have been played by professionals and gives statistics on win/loss ratio in opening situations.
Internet-based Go servers
allow access to competition with players all over the world, for real-time and turn-based games.Lists of Go servers are kept at Sensei's Library and the AGA website Such servers also allow easy access to professional teaching, with both teaching games and interactive game review being possible.The British Go Association provides a list of teaching services
.
by Nobel prize
-winning author Yasunari Kawabata
A list of books can be found at Sensei's Library and The Girl Who Played Go by Shan Sa. Other books have used Go as a theme
or minor plot device. For example, the 1979 novel Shibumi
by Trevanian
centers around the game and uses Go metaphors. Go, referred to as Weiqi, features prominently in the 1986 Eric Van Lustbader
novel Jian.
Similarly, Go has been used as a subject or plot device in film, such as π
, A Beautiful Mind
and Tron: Legacy. Also in The Go Master
, a biopic of Go professional Go Seigen
.A list of films can de found at the EGF Internet Go Filmography In King Hu
's wuxia
film The Valiant Ones, the characters are color-coded as Go pieces (black or other dark shades for the Chinese, white for the Japanese invaders), Go boards and stones are used by the characters to keep track of soldiers prior to battle, and the battles themselves are structured like a game of Go. Go is used as a device for criminal profiling in the pilot episode of Criminal Minds
, "Extreme Aggressor".
In the television series Andromeda
, flashbacks revealed that Captain Hunt used to play Go with his first officer, Gaheris Rhade. Hunt once caught Rhade cheating at the game by removing some of Hunt's stones when Hunt wasn't looking. Rhade's explanation for his cheating--that losing at a competition would call into question the quality of his genes, which would be a horrible outcome for a Nietzschean--was partially intended as a warning to Hunt that Rhade would later betray him.
Of particular note is the manga
(Japanese comic book) and anime
series Hikaru no Go
, released in Japan in 1998, which had a large impact in popularizing Go among young players, both in Japan and—as translations were released—abroad.
The video game company Atari was named after a Go term. Atari's founder Nolan Bushnell was quoted as saying: "In Go, when you are about to capture an opponent's piece, you politely warn them 'Atari' [check]. I felt that was a good aggressive name for a company."
Go has appeared in American films with great rarity. In Heaven Knows, Mr. Allison
, Japanese officers are seen playing Go, and Sister Angela tells Corporal Allison (incorrectly) that the purpose of the game is to capture your opponent's stones. In Heathers
, Veronica has a Go board in her bedroom. (The board is not visible in the cropped TV version.) In Tron: Legacy, Flynn plays Go. It is believed that Stanley Kubrick
wanted HAL 9000
to play Go, but chess was used instead. Kubrick was an experienced chess player, so he may have found Go more mysterious. In the television series Arrested Development characters Maebe and Anyang are seen playing Go in the concluding minute of the final episode of the first season, "Let 'Em Eat Cake
."
of Go, compared with other traditional board games such as chess and Mancala
. Computer Go research has shown that given the large search tree, knowledge and pattern recognition are more important in Go than in other strategy games, such as chess. A study of the effects of age on Go-playing has shown that mental decline is milder with strong players than with weaker players. According to the review of Gobet and colleagues, the pattern of brain activity observed with techniques such as PET
and fMRI
does not show large differences between Go and chess. On the other hand, a study by Xiangchuan Chen et al. showed greater activation in the right hemisphere among Go players than among chess players. There is some evidence to suggest a correlation between playing board games and reduced risk of Alzheimer's disease
and dementia
.
Historical interest:
Board game
A board game is a game which involves counters or pieces being moved on a pre-marked surface or "board", according to a set of rules. Games may be based on pure strategy, chance or a mixture of the two, and usually have a goal which a player aims to achieve...
for two players that originated in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
more than 2,000 years ago. The game is noted for being rich in strategy despite its relatively simple rules.
The game is played by two players who alternately place black and white stones on the vacant intersections (called "points") of a grid of 19×19 lines (beginners often play on smaller 9×9 and 13×13 boards). The object of the game is to use one's stones to surround a larger portion of the board than the opponent. Once placed on the board, stones cannot be moved, though they can be removed if they are captured. When a game concludes, the controlled points (territory) are counted along with captured stones to determine who has more points. Games may also be won by resignation.
Placing stones close together usually helps them support each other and avoid capture, while placing stones far apart creates influence across more of the board. Part of the strategic difficulty of the game stems from finding a balance between these types of conflicting interests. Players strive to serve both defensive and offensive purposes and choose between tactical urgency and strategic plans. At its basis, the game is one of simple logic, while in advanced play the game involves complex heuristic
Heuristic
Heuristic refers to experience-based techniques for problem solving, learning, and discovery. Heuristic methods are used to speed up the process of finding a satisfactory solution, where an exhaustive search is impractical...
s and tactical analysis. Beginning players first learn the simple mechanics of how stones interact, while intermediate students learn concepts such as initiative ("sente"), influence, and the proper timing of moves.
Go originated in ancient China; exactly when is unknown. By the 3rd century BC it was already a popular pastime, as indicated by a reference to the game in the Analects of Confucius
Analects of Confucius
The Analects, or Lunyu , also known as the Analects of Confucius, are considered a record of the words and acts of the central Chinese thinker and philosopher Confucius and his disciples, as well as the discussions they held....
. Archaeological evidence shows that the early game was played on a board with a 17×17 grid, but by the time the game had spread to Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...
and Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, in about the 5th and 7th centuries respectively, boards with a 19×19 grid had become standard.
The game is most popular in East Asia. A survey done in 2003 places the number of Go players worldwide at approximately 27 million. Go reached the West through Japan, which is why it is commonly known internationally by its shortened Japanese name, and why terms for common Go concepts
Go terms
Players of the game of Go often use jargon to describe situations on the board and surrounding the game. Such technical terms are likely to be encountered in books and articles about Go in English as well as other languages. Many of these terms have been borrowed from Japanese, mostly when no short...
are commonly derived from its Japanese pronunciation. The full Japanese name igo is derived from its Chinese name weiqi, which roughly translates as "board game of surrounding."The full Japanese name igo is derived from its Chinese name weiqi, which roughly translates as "board game of surrounding", see Etymology Of Go at Sensei's Library for more information. To differentiate the game Go from the common English verb to go
Go (verb)
Go is an irregular English verb whose basic definition is "to move from one place to another". Be and go are the only English verbs with a suppletive past tense.-Principal parts:...
, it is generally capitalized (Gao 2007) or, in events sponsored by the Ing
Ing Chang-ki
Ing Chang-ki was a Taiwan industrialist, Go player, and Go promoter. He was the founder of the Ing Cup. He is also known for inventing and promoting the Ing Rules of Go. He also promoted one of the first digital game clocks to support byoyomi.-Biography:...
Foundation, spelled goe.
Overview
Go is an adversarial game with the objective of surrounding more territory than one's opponent. As the game progresses, the board gets divided up into areas of territory, as outlined by groups of stones. These areas are then contested in local battles. These battles may be complicated and may result in the expansion, reduction, or wholesale capture/loss of the contested area.The basic principle of Go is that stones must have "liberty" to remain on the board. A liberty is an open point (intersection) next to a stone. An enclosed liberty is called an "eye," and a group of stones with at least two eyes is said to be unconditionally alive. Such groups cannot be captured. Dead stones are those which are surrounded and have poor shape (one or no eyes) and thus cannot resist eventual capture.
The general strategy of Go is to expand one's territory where possible, attack the opponent's weak groups (groups which can possibly be killed), and always stay mindful of the "life status
Life and death
Life and death is a fundamental concept in the game of Go, where the status of a distinct group of stones is determined as either being "alive", and may remain on the board indefinitely, or "dead," where the group will be lost as "captured"...
" of one's own groups.
The liberties of groups are countable and it is often important to keep track of their number. In cases where two opposing groups must capture the other to live, these "capturing races" ("semeai") all ultimately reduce to a logical and concrete contest of relative liberties —the group with the more liberties (and/or "better shape") will capture the opponent stones and thus live. Semeais and life and death problems are examples of where parts of the game can form a type of puzzle
Puzzle
A puzzle is a problem or enigma that tests the ingenuity of the solver. In a basic puzzle, one is intended to put together pieces in a logical way in order to come up with the desired solution...
. Solving the puzzle means accurately observing and understanding the situation and making the appropriate move. For example one may have to make a move to save one of their own groups, or one may have an opportunity to kill an opponent's group and thus capture some stones and territory.
The game's opening stages largely deal with establishing "bases" (or 'footholds') around the sides of the board. These bases help to quickly establish living shapes. There are special properties associated with the corners as well, which are studied in corner opening sequences ("joseki
Joseki
In Go, are studied sequences of moves in the corner areas of the Go board, for which the result is considered balanced for both black and white sides. Because games typically start with plays in the corners, players often try to use their understanding of joseki to gain local advantages in the...
") and in many life and death problems. The first principle of opening theory is to play in the corners, because it is more efficient there to make life and to establish territory. The game ends when both players pass. Players pass when there are no more profitable moves to be made —when playing within one's own territory removes points from one's score, and when playing within the opponent's territory will be fruitless.
"Dame" are points that lie in-between the boundary walls of Black and White, and as such are considered to be of no value to either side. "Sekis" are mutually alive groups without two eyes. A "ko" is a repeated-position shape which may be contested by making forcing moves elsewhere. After the forcing move is played, the ko may be "taken back" and returned to its original position. Some "ko fights" may be important and decide the life of a large group, while others may simply be worth one or two points. There are different rule-sets (Japanese, Chinese, AGA, etc.) which end up being almost entirely equivalent except for certain special-case positions.
Rules
Although there are some minor differences between rule sets used in different countries, most notably in Chinese and Japanese scoring rules, these differences do not seriously affect the tactics and strategy of the game. Except where noted otherwise, the basic rules presented here are valid independent of the scoring rules used. The scoring rules are explained separately. Go conceptsGo terms
Players of the game of Go often use jargon to describe situations on the board and surrounding the game. Such technical terms are likely to be encountered in books and articles about Go in English as well as other languages. Many of these terms have been borrowed from Japanese, mostly when no short...
for which there is no ready English equivalent are commonly called by their Japanese names.
Basic rules
Vertically and horizontally adjacent stones of the same color form a chain (also called a string, or simply a group) that shares its liberties (see below) in common, cannot subsequently be subdivided, and in effect becomes a single larger stone. Only stones connected to one another by the lines on the board create a chain; stones that are diagonally adjacent are not connected. Chains may be expanded by placing additional stones on adjacent intersections, and can be connected together by placing a stone on an intersection that is adjacent to two or more chains of the same color.
Liberty (division)
Originating in the Middle Ages, a liberty was traditionally defined as an area in which regalian rights were revoked and where land was held by a mesne lord...
", a small local government unit in medieval England – the "local area under control". Stones in a chain share their liberties. A chain of stones must have at least one liberty to remain on the board. When a chain is surrounded by opposing stones so that it has no liberties, it is captured and removed from the board.
The ko rule
Players are not allowed to make a move that returns the game to a previous position. This rule, called the ko rule (from the Japanese 劫 kō "eon"), prevents unending repetition. See the example to the right: Black has just played the stone marked 1, capturing a white stone at the intersection marked with a circle. If White were now allowed to play on the marked intersection, that move would capture the black stone marked 1 and recreate the situation before Black made the move marked 1. Allowing this could result in an unending cycle of captures by both players. The ko rule therefore prohibits White from playing at the marked intersection immediately. Instead White must play elsewhere; Black can then end the ko by filling at the marked intersection, creating a five-stone Black chain. If White wants to continue the ko (that specific repeating position), White will try to find a play elsewhere on the board that Black must answer; if Black answers, then White can retake the ko. A repetition of such exchanges is called a ko fight.While the various rule sets agree on the ko rule prohibiting returning the board to an immediately previous position, they deal in different ways with the relatively uncommon situation in which a player might recreate a past position that is further removed. See Rules of Go: Repetition for further information.
Passing
Instead of placing a stone, a player may pass. This usually occurs when they believe no useful moves remain. When both players pass consecutively, the game ends and is then scored.Playing Stones With No Liberties
A player may not place a stone such that it or its group immediately has no liberties, unless doing so will immediately deprive an enemy group of its final liberty. In the latter case, the enemy group is captured, leaving the new stone with at least one liberty. This rule is responsible for the all-important difference between one and two eyes: if a group with only one eye is fully surrounded on the outside, it can be killed with a stone placed in its single eye.The Chinese rules allow an exception to this rule, such that a player might destroy one of its own groups--"commit suicide." This play would only be useful in a limited set of situations involving a small interior space.
Komi
Because Black has a first move advantageKomidashi
in the game of Go are points added to the score of the player with the white stones as compensation for playing second. Black's first move advantage is generally considered to equal somewhere between 5 and 7 points by the end of the game. Standard komi is 6.5 points under the Japanese and Korean...
, the idea of awarding White some compensation came into being during the 20th century. This predetermined compensation, called "komidashi
Komidashi
in the game of Go are points added to the score of the player with the white stones as compensation for playing second. Black's first move advantage is generally considered to equal somewhere between 5 and 7 points by the end of the game. Standard komi is 6.5 points under the Japanese and Korean...
," ("komi") means that for even games white may receive somewhere on average of 6.5 points compensation for Black's first move advantage. If there is one stone difference in strength between players, the stronger player takes White, and White may receive only .5 points komi, just to break a possible tie ("jigo"). In handicap games with 2 or more handicap stones, White may also take .5 points komi to break a tie.
Scoring rules
Two general types of scoring system are used, and players determine which to use before play. Both systems almost always give the same result. Territory scoring counts the number of empty points a player's stones surround, together with the number of stones he captured. While it originated in China, today it is commonly associated with Japan and Korea. Area scoring counts the number of points your stones occupy and surround. It is associated with contemporary Chinese play and was probably established there during the Ming DynastyMing Dynasty
The Ming Dynasty, also Empire of the Great Ming, was the ruling dynasty of China from 1368 to 1644, following the collapse of the Mongol-led Yuan Dynasty. The Ming, "one of the greatest eras of orderly government and social stability in human history", was the last dynasty in China ruled by ethnic...
in the 15th or 16th century.
Detailed description
After both players have passed consecutively, the stones that are still on the board but unable to avoid capture, called dead stones, are removed.Area scoring (including Chinese): A player's score is the number of stones he has on the board, plus the number of empty intersections surrounded by that player's stones.
Territory scoring (including Japanese and Korean): In the course of the game, each player retains the stones they capture, termed prisoners. Any dead stones removed at the end of the game become prisoners. The score is the number of empty points enclosed by a player's stones, plus the number of prisoners captured by that player.Exceptionally, in Japanese and Korean rules, empty points, even those surrounded by stones of a single colour, may count as neutral territory if some of them are alive by seki. See the section on "Life and Death" for seki.
If there is disagreement about which stones are dead, then under area scoring rules, the players simply resume play to resolve the matter. The score is computed using the position after the next time the players pass consecutively. Under territory scoring, the rules are considerably more complex; however, in practice, players will generally play on, and, once the status of each stone has been determined, return to the position at the time the first two consecutive passes occurred and remove the dead stones. For further information, see Rules of Go
Rules of Go
This is an in-depth discussion of the rules of go.There has been a certain amount of variation in the rules of go over time, and from place to place. This article discusses those sets of rules broadly similar to the ones currently in use in East Asia. Even among these, there is a degree of...
.
Given that the number of stones a player has on the board is related to the number of prisoners the opponent has taken, the resulting net score (the difference between Black and White's respective scores) under both rulesets is often identical and rarely differs by more than a point.
Life and death
While not actually mentioned in the rules of Go (at least in simpler rule sets, such as those of New Zealand and the US), the concept of a living group of stones is necessary for a practical understanding of the game.When a group of stones is mostly surrounded and has no options to connect with friendly stones elsewhere, the status of the group is either alive, dead or unsettled. A group of stones is said to be alive if it cannot be captured, even if the opponent is allowed to move first. Conversely, a group of stones is said to be dead if it cannot avoid capture, even if the owner of the group is allowed the first move. Otherwise, the group is said to be unsettled: in such a situation, the player that moves first may be able to either make it alive if he is the owner, or kill it if he is the group owner's opponent.
To be alive, a group must be able to create at least two "eyes" if threatened. An eye is an empty point that is surrounded by friendly stones, where the opponent can never play due to the suicide rule. If two such eyes exist, the opponent can never capture a group of stones, because it will always have at least two liberties. One eye is not enough for life, because a point that would normally be suicide may be played upon if doing so fills the last liberty of opposing stones, thereby capturing those stones. In the "Examples of eyes" diagram, all the circled points are eyes. The two black groups in the upper corners are alive, as both have at least two eyes. The groups in the lower corners are dead, as both have only one eye. The group in the lower left may seem to have two eyes, but the surrounded empty point without a circle is not actually an eye. White can play there and take a black stone. Such a point is often called a false eye.
Seki / mutual life
There is an exception to the requirement that a group must have two eyes to be alive, a situation called seki (or mutual life). Where different coloured groups are adjacent and share liberties, the situation may reach a position when neither player wants to move first, because doing so would allow the opponent to capture; in such situations therefore both player's stones remain on the board in mutual life or "seki". Neither player receives any points for those groups, but at least those groups themselves remain living, as opposed to being captured.In game theoretical terms, seki positions are an example of a Nash equilibriumNash equilibrium
In game theory, Nash equilibrium is a solution concept of a game involving two or more players, in which each player is assumed to know the equilibrium strategies of the other players, and no player has anything to gain by changing only his own strategy unilaterally...
.
Sekis can occur in many ways. The simplest are: (1) each player has a group without eyes and they share two liberties, and (2) each player has a group with one eye and they share one more liberty. In the "Example of seki (mutual life)" diagram, the circled points are liberties shared by both a black and a white group. Neither player wants to play on a circled point, because doing so would allow the opponent to capture. All the other groups in this example, both black and white, are alive with at least two eyes. Sekis are unusual, but can result from an attempt by one player to invade and kill a nearly settled group of the other player.
Tactics
In Go, tactics deal with immediate fighting between stones, capturing and saving stones, life, death and other issues localized to a specific part of the board. Larger issues, not limited to only part of the board, are referred to as strategy, and are covered in their own section.Capturing tactics
There are several tactical constructs aimed at capturing stones. These are among the first things a player learns after understanding the rules. Recognizing the possibility that stones can be captured using these techniques is an important step forward.The most basic technique is the ladder. To capture stones in a ladder, a player uses a constant series of capture threats—called atari—to force the opponent into a zigzag pattern as shown in the diagram to the right. Unless the pattern runs into friendly stones along the way, the stones in the ladder cannot avoid capture. Experienced players will recognize the futility of continuing the pattern and will play elsewhere. The presence of a ladder on the board does give a player the option to play a stone in the path of the ladder, thereby threatening to rescue their stones, forcing a response. Such a move is called a ladder breaker and may be a powerful strategic move. In the diagram, Black has the option of playing a ladder breaker.
Another technique to capture stones is the so-called net, also known by its Japanese name, geta. This refers to a move that loosely surrounds some stones, preventing their escape in all directions. An example is given in the diagram to the left. It is generally better to capture stones in a net than in a ladder, because a net does not depend on the condition that there are no opposing stones in the way, nor does it allow the opponent to play a strategic ladder breaker.
A third technique to capture stones is the snapback. In a snapback, one player allows a single stone to be captured, then immediately plays on the point formerly occupied by that stone; by so doing, the player captures a larger group of their opponent's stones, in effect snapping back at those stones. An example can be seen on the right. As with the ladder, an experienced player will not play out such a sequence, recognizing the futility of capturing only to be captured back immediately.
Reading ahead
One of the most important skills required for strong tactical play is the ability to read ahead. Reading ahead includes considering available moves to play, the possible responses to each move, and the subsequent possibilities after each of those responses. Some of the strongest players of the game can read up to 40 moves ahead even in complicated positions.As explained in the scoring rules, some stone formations can never be captured and are said to be alive, while other stones may be in the position where they cannot avoid being captured and are said to be dead. Much of the practice material available to students of the game comes in the form of life and death problems, also known as tsumego
Tsumego
is the Japanese term for a Go problem based on life-and-death. The term likely comes from , as means mating in Shogi but has no meaning in Go. Tsumego problems are common in newspaper columns; the usual format is of a position set up on some delimited area of the board, and the instruction reads...
. In such problems, players are challenged to find the vital move sequence that will kill a group of the opponent or save a group of their own. Tsumego are considered an excellent way to train a player's ability at reading ahead, and are available for all skill levels, some posing a challenge even to top players.
Ko fighting
In situations when the Ko rule applies, a ko fight may occur. If the player who is prohibited from capture is of the opinion that the capture is important, because it prevents a large group of stones from being captured for instance, the player may play a ko threat. This is a move elsewhere on the board that threatens to make a large profit if the opponent does not respond. If the opponent does respond to the ko threat, the situation on the board has changed, and the prohibition on capturing the ko no longer applies. Thus the player who made the ko threat may now recapture the ko. Their opponent is then in the same situation and can either play a ko threat as well, or concede the ko by simply playing elsewhere. If a player concedes the ko, either because they do not think it important or because there are no moves left that could function as a ko threat, they have lost the ko, and their opponent may connect the ko.Instead of responding to a ko threat, a player may also choose to ignore the threat and connect the ko. They thereby win the ko, but at a cost. The choice of when to respond to a threat and when to ignore it is a subtle one, which requires a player to consider many factors, including how much is gained by connecting, how much is lost by not responding, how many possible ko threats both players have remaining, what the optimal order of playing them is, and what the size—points lost or gained—of each of the remaining threats is.
Frequently, the winner of the ko fight does not connect the ko but instead captures one of the chains that constituted their opponent's side of the ko. In some cases, this leads to another ko fight at a neighboring location.
Strategy
Strategy deals with global influence, interaction between distant stones, keeping the whole board in mind during local fights, and other issues that involve the overall game. It is therefore possible to allow a tactical loss when it confers a strategic advantage.Go is not easy to play well. With each new level (rank) comes a deeper appreciation for the subtlety and nuances involved and for the insight of stronger players. The acquisition of major concepts of the game comes slowly. Novices often start by randomly placing stones on the board, as if it were a game of chance; they inevitably lose to experienced players who know how to create effective formations. An understanding of how stones connect for greater power develops, and then a few basic common opening sequences
Go opening theory
In the game of Go, the term opening theory refers to concepts which underlie where, why, in what order, and in what shapes the first several moves are played...
may be understood. Learning the ways of life and death helps in a fundamental way to develop one's strategic understanding of weak groups. It is necessary to play thousands of games before one can get close to one's ultimate potential skill level in Go. A player who both plays aggressively and can handle adversity is said to display kiai
Kiai
is a Japanese term used in martial arts. There are numerous examples of the battle cry in other cultures: kiai is perhaps primarily a development of this. In the representation of Asian martial arts in cinema and in animated cartoons, Modern Kiai are often written by westerners in Romaji as...
, or fighting spirit, in the game.
Familiarity with the board shows first the tactical importance of the edges, and then the efficiency of developing in the corners first, then sides, then center. The more advanced beginner understands that territory and influence are somewhat interchangeable—but there needs to be a balance. This intricate struggle of power and control makes the game highly dynamic.
Basic concepts
Basic strategic aspects include the following:- Connection: Keeping one's own stones connected means that fewer groups need to make living shape, and one will have fewer groups to defend.
- Cut: Keeping opposing stones disconnected means that the opponent needs to defend and make living shape for more groups.
- Stay alive: The simplest way to stay alive is to establish a foothold in the corner or along one of the sides. At a minimum, a group must have two eyes (separate open points) to be "alive." An opponent cannot fill in either eye, as any such move is suicidal and prohibited in the rules.
- Mutual life (seki) is better than dying: A situation in which neither player can play to a particular point without then allowing the other player to play at another point to capture. The most common example is that of adjacent groups that share their last few liberties —if either player plays in the shared liberties, they can reduce their own group to a single liberty (putting themselves in atari), allowing their opponent to capture it on the next move.
- Death: A group that lacks living shape, meaning less than two eyes, will eventually be removed from the board as captured.
- Invasion: Set up a new living group inside an area where the opponent has greater influence, means one will reduce the opponents score in proportion to the area one occupies.
- Reduction: Placing a stone far enough into the opponent's area of influence to reduce the amount of territory they will eventually get, but not so far in that it can be cut off from friendly stones outside.
- Sente: A play that forces one's opponent to respond (goteGo termsPlayers of the game of Go often use jargon to describe situations on the board and surrounding the game. Such technical terms are likely to be encountered in books and articles about Go in English as well as other languages. Many of these terms have been borrowed from Japanese, mostly when no short...
), such as placing an opponent's group in atari (immediate danger of capture). A player who can regularly play sente has the initiative, as in chess, and can control the flow of the game. - Sacrifice: Allowing a group to die in order to carry out a play, or plan, in a more important area.
The strategy involved can become very abstract and complex. High-level players spend years improving their understanding of strategy, and a novice may play many hundreds of games against opponents before being able to win regularly.
Opening strategy
In the opening of the game, players will usually play in the corners of the board first, as the presence of two edges make it easier for them to surround territory and establish their stones. After the corners, focus moves to the sides, where there is still one edge to support a player's stones. Opening moves are generally on the third and fourth line from the edge, with occasional moves on the second and fifth lines. In general, stones on the third line offer stability and are good defensive moves, whereas stones on the fourth line influence more of the board and are good attacking moves.In the opening, players often play established sequences called joseki
Joseki
In Go, are studied sequences of moves in the corner areas of the Go board, for which the result is considered balanced for both black and white sides. Because games typically start with plays in the corners, players often try to use their understanding of joseki to gain local advantages in the...
, which are locally balanced exchanges; however, the joseki chosen should also produce a satisfactory result on a global scale. It is generally advisable to keep a balance between territory and influence. Which of these gets precedence is often a matter of individual taste.
Phases of the game
While the opening moves in a game have a distinct set of aims, they usually make up only 10% to at most 20% of the game. In other words, in a game of 250 moves, there may be around 30 or so opening moves, with limited "fighting". At the end of such a game, there will also be perhaps 100 moves that are counted as "endgame", in which territories are finished off definitively and all issues on capturing stones become clear. The middle phase of the game is the most combative, and usually lasts for more than 100 moves. During the middlegame, or just "the fighting", the players invade each others' frameworks, and attack weak groups, formations that lack the necessary two eyes for viability. Such groups must run away, i.e. expand to avoid enclosure, giving a dynamic feeling to the struggle. It is quite possible that one player will succeed in capturing a large weak group of the opponent's, which will often prove decisive and end the game by a resignation. But matters may be more complex yet, with major trade-offs, apparently dead groups reviving, and skillful play to attack in such a way as to construct territories rather than to kill.The end of the middlegame and transition to the endgame is marked by a few features. The game breaks up into areas that do not affect each other (with a caveat about ko fights), where before the central area of the board related to all parts of it. No large weak groups are still in serious danger. Moves can reasonably be attributed some definite value, such as 20 points or fewer, rather than simply being necessary to compete. Both players set limited objectives in their plans, in making or destroying territory, capturing or saving stones. These changing aspects of the game usually occur at much the same time, for strong players. In brief, the middlegame switches into the endgame when the concepts of strategy and influence need reassessment in terms of concrete final results on the board.
Origin in China
The earliest written reference to the game is generally recognized as the historical annal Zuo ZhuanZuo Zhuan
The Zuo Zhuan , sometimes translated as the Chronicle of Zuo or the Commentary of Zuo, is among the earliest Chinese works of narrative history and covers the period from 722 BCE to 468 BCE. It is one of the most important sources for understanding the history of the Spring and Autumn Period...
(c. 4th century BC), referring to a historical event of 548 BC. It is also mentioned in Book XVII of the Analects of Confucius
Analects of Confucius
The Analects, or Lunyu , also known as the Analects of Confucius, are considered a record of the words and acts of the central Chinese thinker and philosopher Confucius and his disciples, as well as the discussions they held....
and in two books written by Mencius
Mencius
Mencius was a Chinese philosopher who was arguably the most famous Confucian after Confucius himself.-Life:Mencius, also known by his birth name Meng Ke or Ko, was born in the State of Zou, now forming the territory of the county-level city of Zoucheng , Shandong province, only thirty kilometres ...
(c. 3rd century BC). In all of these works, the game is referred to as . Today, in China, it is known as weiqi , literally the "encirclement board game".
Go was originally played on a 17×17 line grid, but a 19×19 grid became standard by the time of the Tang Dynasty
Tang Dynasty
The Tang Dynasty was an imperial dynasty of China preceded by the Sui Dynasty and followed by the Five Dynasties and Ten Kingdoms Period. It was founded by the Li family, who seized power during the decline and collapse of the Sui Empire...
(618–907). Legends trace the origin of the game to Chinese emperor
Emperor of China
The Emperor of China refers to any sovereign of Imperial China reigning between the founding of Qin Dynasty of China, united by the King of Qin in 221 BCE, and the fall of Yuan Shikai's Empire of China in 1916. When referred to as the Son of Heaven , a title that predates the Qin unification, the...
Yao (2337–2258 BC), said to have had his counselor Shun design it for his unruly son, Danzhu, to favorably influence him. Other theories suggest that the game was derived from Chinese tribal warlords and generals, who used pieces of stone to map out attacking positions.
In China, Go was considered one of the four cultivated arts
Four Arts of the Chinese Scholar
The Four Arts of the Chinese Scholar, otherwise known as siyi , is a term used to describe four main accomplishments required of the Chinese scholar gentleman...
of the Chinese scholar gentleman
Junzi
Junzi or nobleman, was a term used by Confucius , to describe his ideal human. To Confucius, the functions of government and social stratification were facts of life to be sustained by ethical values; thus his ideal human was the junzi...
, along with calligraphy, painting
Chinese painting
Chinese painting is one of the oldest continuous artistic traditions in the world. The earliest paintings were not representational but ornamental; they consisted of patterns or designs rather than pictures. Early pottery was painted with spirals, zigzags, dots, or animals...
and playing the musical instrument guqin
Guqin
The guqin is the modern name for a plucked seven-string Chinese musical instrument of the zither family...
.
Spread to Korea and Japan
Weiqi was introduced to Korea sometime between the 5th and 7th centuries AD, and was popular among the higher classes. In Korea, the game is called baduk (hangulHangul
Hangul,Pronounced or ; Korean: 한글 Hangeul/Han'gŭl or 조선글 Chosŏn'gŭl/Joseongeul the Korean alphabet, is the native alphabet of the Korean language. It is a separate script from Hanja, the logographic Chinese characters which are also sometimes used to write Korean...
: ), and a variant of the game called Sunjang baduk
Sunjang baduk
Sunjang baduk is a variant of the game baduk—more commonly known in English as Go—which originated in Korea in the 16th century. Its rules of play are similar to normal baduk, but the rules for counting the score differ significantly....
was developed by the 16th century. Sunjang baduk became the main variant played in Korea until the end of the 19th century.
Tokugawa Ieyasu
was the founder and first shogun of the Tokugawa shogunate of Japan , which ruled from the Battle of Sekigahara in 1600 until the Meiji Restoration in 1868. Ieyasu seized power in 1600, received appointment as shogun in 1603, abdicated from office in 1605, but...
re-established Japan's unified national government. In the same year, he assigned the then-best player in Japan, a Buddhist monk named Nikkai (né Kanō Yosaburo, 1559), to the post of Godokoro
Godokoro
is a title that was given in Japan from the beginning of the Edo period until the Meiji Restoration. In that period it was the highest official standing that could be attained by a go player. Literally it is a metonym, meaning the 'go office'....
(Minister of Go). Nikkai took the name Honinbo Sansa
Honinbo Sansa
Honinbō Sansa was the assumed name of Kanō Yosaburō , one of the strongest Japanese Go players of the Edo period , and founder of the house of Honinbō, first among the four great schools of Go in Japan...
and founded the Honinbo Go school. Several competing schools
Four go houses
In the history of go in Japan, the Four go houses were the four academies of Go instituted, supported, and controlled by the state, at the beginning of the Tokugawa shogunate. At roughly the same time shogi was organised into three houses. Here 'house' implies institution run on the recognised...
were founded soon after. These officially recognized and subsidized Go schools greatly developed the level of play and introduced the dan/kyu style system
Go ranks and ratings
Skill in the traditional board game Go is measured by a number of different national, regional and online ranking and rating systems. Traditionally, go rankings have been measured using a system of dan and kyu ranks...
of ranking players. Players from the four schools (Honinbo, Yasui, Inoue and Hayashi) competed in the annual castle games, played in the presence of the shogun
Shogun
A was one of the hereditary military dictators of Japan from 1192 to 1867. In this period, the shoguns, or their shikken regents , were the de facto rulers of Japan though they were nominally appointed by the emperor...
.
Go in the West
Despite its widespread popularity in East Asia, Go has been slow to spread to the rest of the world. Although there are some mentions of the game in western literature from the 16th century forward, Go did not start to become popular in the West until the end of the 19th century, when German scientist Oskar KorscheltOskar Korschelt
Oskar Korschelt was a German chemist and engineer who introduced the Asian strategy board game of Go to Europe, especially to Germany and Austria.He was an industrial chemist working in the brewing industry...
wrote a treatise on the game. By the early 20th century, Go had spread throughout the German
German Empire
The German Empire refers to Germany during the "Second Reich" period from the unification of Germany and proclamation of Wilhelm I as German Emperor on 18 January 1871, to 1918, when it became a federal republic after defeat in World War I and the abdication of the Emperor, Wilhelm II.The German...
and Austro-Hungarian
Austria-Hungary
Austria-Hungary , more formally known as the Kingdoms and Lands Represented in the Imperial Council and the Lands of the Holy Hungarian Crown of Saint Stephen, was a constitutional monarchic union between the crowns of the Austrian Empire and the Kingdom of Hungary in...
empires. In 1905, Edward Lasker
Edward Lasker
Edward Lasker was a leading German-American chess and Go player. He was awarded the title of International Master of chess by FIDE. Lasker was an engineer by profession, and an author.-Background:...
learned the game while in Berlin. When he moved to New York, Lasker founded the New York Go Club together with (amongst others) Arthur Smith, who had learned of the game while touring the East and had published the book The Game of Go in 1908. Lasker's book Go and Go-moku (1934) helped spread the game throughout the US, and in 1935, the American Go Association was formed. Two years later, in 1937, the German Go Association was founded.
World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
put a stop to most Go activity, but after the war, Go continued to spread. For most of the 20th century, the Japan Go Association
Nihon Ki-in
The Nihon Ki-in , also known as the Japan Go Association, is the main organizational body for Go in Japan, overseeing Japan's professional system and issuing diplomas for amateur dan rankings. It is based in Tokyo. The other major Go association in Japan is Kansai Ki-in.Nihon Ki-in was established...
played a leading role in spreading Go outside East Asia by publishing the English-language magazine Go Review in the 1960s; establishing Go centers
Go centers
As part of the effort to spread the game of Go throughout the world, several Go centers were founded in the US, Europe and South American. A large part of the required funds was contributed by the Iwamoto Foundation...
in the US, Europe and South America; and often sending professional teachers on tour to Western nations.
In 1996, NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
astronaut Daniel Barry
Daniel T. Barry
Daniel Thomas Barry is an American engineer, scientist, and a retired NASA astronaut. He was a contestant on the CBS reality television program Survivor: Panama-Exile Island...
and Japanese astronaut Koichi Wakata
Koichi Wakata
is a Japanese engineer and a JAXA astronaut. Wakata is a veteran of four NASA Space Shuttle missions and a long-duration stay on the International Space Station. During a nearly two decade career in spaceflight he has logged five months in space. Wakata is currently assigned to the Soyuz...
became the first people to play Go in space. Both astronauts were awarded honorary dan rank
Dan rank
The ranking system is a Japanese mark of level, which is used in modern fine arts and martial arts. Originally invented in a Go school in the Edo period, this system was applied to martial arts by Kanō Jigorō, the founder of judo and later introduced to other East Asia countries.In the modern...
s by the Nihon Ki-in
Nihon Ki-in
The Nihon Ki-in , also known as the Japan Go Association, is the main organizational body for Go in Japan, overseeing Japan's professional system and issuing diplomas for amateur dan rankings. It is based in Tokyo. The other major Go association in Japan is Kansai Ki-in.Nihon Ki-in was established...
.
, the International Go Federation
International Go Federation
The International Go Federation is an international organization that connects the various national Go federations around the world. It is usually referred to as IGF.-Role of the IGF:...
has a total of 71 member countries. It has been claimed that across the world 1 person in every 222 plays Go.
Ranks and ratings
Martial arts
Martial arts are extensive systems of codified practices and traditions of combat, practiced for a variety of reasons, including self-defense, competition, physical health and fitness, as well as mental and spiritual development....
. More recently, mathematical rating systems similar to the Elo rating system
Elo rating system
The Elo rating system is a method for calculating the relative skill levels of players in two-player games such as chess. It is named after its creator Arpad Elo, a Hungarian-born American physics professor....
have been introduced. Such rating systems often provide a mechanism for converting a rating to a kyu or dan grade. Kyu grades (abbreviated k) are considered student grades and decrease as playing level increases, meaning 1st kyu is the strongest available kyu grade. Dan grades (abbreviated d) are considered master grades, and increase from 1st dan to 7th dan. First dan
Shodan
, literally meaning "beginning degree," is the lowest black belt rank in Japanese martial arts and the game of Go. The 2nd dan is higher than Shodan, but the 1st dan is called Shodan traditionally and the 1st dan is not called "Ichidan"...
equals a black belt
Black belt (martial arts)
In martial arts, the black belt is a way to describe a graduate of a field where a practitioner's level is often marked by the color of the belt. The black belt is commonly the highest belt color used and denotes a degree of competence. It is often associated with a teaching grade though...
in eastern martial arts using this system. The difference among each amateur rank is one handicap stone. For example, if a 5k plays a game with a 1k, the 5k would need a handicap of four stones to even the odds. Top-level amateur players sometimes defeat professionals in tournament play. Professional players have professional dan ranks
Go professional
A Go professional is a professional player of the game of Go. The minimum standard to acquire a professional diploma through one of the major go organisations is very high. The competition is tremendous, and prize incentives for champion players are very large...
(abbreviated p). These ranks are separate from amateur ranks.
The rank system comprises, from the lowest to highest ranks:
| Rank Type | Range | Stage |
|---|---|---|
| Double-digit kyu | 30–20k | Beginner |
| Double-digit kyu | 19–10k | Casual player |
| Single-digit kyu | 9–1k | Intermediate/club player |
| Amateur dan | 1–7d (where 8d is special title) | Expert player |
| Professional dan | 1–9p (where 10p is special title) | Professionals |
Tournament and match rules
Tournament and match rules deal with factors that may influence the game but are not part of the actual rules of play. Such rules may differ between events. Rules that influence the game include: the setting of compensation points (komiKomidashi
in the game of Go are points added to the score of the player with the white stones as compensation for playing second. Black's first move advantage is generally considered to equal somewhere between 5 and 7 points by the end of the game. Standard komi is 6.5 points under the Japanese and Korean...
), handicap strategies, and time control parameters. Rules that do not generally influence the game are: the tournament system, pairing strategies, and placement criteria.
Common tournament systems used in Go include the McMahon system, Swiss system
Swiss system tournament
A Swiss-system tournament is a commonly used type of tournament where players or teams need to be paired to face each other for several rounds of competition. This type of tournament was first used in a Zurich chess tournament in 1895, hence the name "Swiss system". The Swiss system is used when...
, league system
League system
A league system is a hierarchy of leagues in a sport, usually with a system of promotion and relegation between consecutive levels of the hierarchy. They are often called pyramids due to their tendency to split into an increasing number of regional divisions the further down the pyramid one descends...
s and the knockout system
Single-elimination tournament
A single-elimination tournament, also called a knockout, cup or sudden death tournament, is a type of elimination tournament where the loser of each match or bracket is immediately eliminated from winning the championship or first prize in the event...
. Tournaments may combine multiple systems; many professional Go tournaments use a combination of the league and knockout systems.
Tournament rules may also set the following:
- compensation points, called komi, which compensate the second player for the first move advantage of his opponent; tournaments commonly use a compensation in the range of 5–8 points, generally including a half-point to prevent draws;
- compensation stones placed on the board before alternate play, allowing players of different strengths to play competitively (see Go handicapGo handicapWithin most systems and at most levels, handicap is given to offset the strength difference between players of different ranks in the game of Go.-Forms of handicaps:In the game of Go, a handicap is given by means of stones and compensation points...
for more information); and - superko: Although the basic ko rule described above covers more than 95% of all cycles occurring in games, there are some complex situations—triple ko, eternal life,A full explanation of the eternal life position can be found on Sensei's Library, it also appears in the official text for Japanese Rules, see translation. etc.—that are not covered by it but would allow the game to cycle indefinitely. To prevent this, the ko rule is sometimes extended to disallow the repetition of any previous position. This extension is called superko.
Top players
Although the game was developed in China, the establishment of the Four Go housesFour go houses
In the history of go in Japan, the Four go houses were the four academies of Go instituted, supported, and controlled by the state, at the beginning of the Tokugawa shogunate. At roughly the same time shogi was organised into three houses. Here 'house' implies institution run on the recognised...
by Tokugawa Ieyasu
Tokugawa Ieyasu
was the founder and first shogun of the Tokugawa shogunate of Japan , which ruled from the Battle of Sekigahara in 1600 until the Meiji Restoration in 1868. Ieyasu seized power in 1600, received appointment as shogun in 1603, abdicated from office in 1605, but...
at the start of the 17th century shifted the focus of the Go world to Japan. State sponsorship, allowing players to dedicate themselves full time to study of the game, and fierce competition between individual houses resulted in a significant increase in the level of play. During this period, the best player of his generation was given the prestigious title Meijin
Meijin
Meijin , literally translated, means "Brilliant Man." It is the name of the second most prestigious Japanese Go Tournament. It also refers to a traditional Japanese title given to the strongest player of the day during the Edo period.- The tournament :...
(master) and the post of Godokoro
Godokoro
is a title that was given in Japan from the beginning of the Edo period until the Meiji Restoration. In that period it was the highest official standing that could be attained by a go player. Literally it is a metonym, meaning the 'go office'....
(minister of Go). Of special note are the players who were dubbed Kisei
Kisei
The Kisei is a Go competition. The title, meaning go sage in Japanese, was a traditional honorary appellation given to a handful of players down the centuries. The element ki can also apply to shogi, and there were also recognized kisei in the shogi world.-Background:Kisei is a Go competition...
(Go Sage). The only three players to receive this honor were Dosaku, Jowa and Shusaku
Honinbo Shusaku
Honinbo Shusaku was a professional Go player and is considered by many to be the greatest player of the golden age of Go in the mid-19th century.- Biography :He was nicknamed "Invincible" after he earned a perfect score for 19 straight wins in the annual castle...
, all of the house Honinbo
Honinbo
Honinbō was the name of one of the four major schools of Go in Japan. Easily the strongest school of Go for most of its existence, it was established in 1612 and survived until 1940....
.
Tokugawa shogunate
The Tokugawa shogunate, also known as the and the , was a feudal regime of Japan established by Tokugawa Ieyasu and ruled by the shoguns of the Tokugawa family. This period is known as the Edo period and gets its name from the capital city, Edo, which is now called Tokyo, after the name was...
and the Meiji Restoration
Meiji Restoration
The , also known as the Meiji Ishin, Revolution, Reform or Renewal, was a chain of events that restored imperial rule to Japan in 1868...
period, the Go houses slowly disappeared, and in 1924, the Nihon Ki-in
Nihon Ki-in
The Nihon Ki-in , also known as the Japan Go Association, is the main organizational body for Go in Japan, overseeing Japan's professional system and issuing diplomas for amateur dan rankings. It is based in Tokyo. The other major Go association in Japan is Kansai Ki-in.Nihon Ki-in was established...
(Japanese Go Association) was formed. Top players from this period often played newspaper-sponsored matches of 2–10 games. Of special note are Go Seigen
Go Seigen
Wu Qingyuan , generally known in the West by his Japanese name Go Seigen, is considered by many players to be the greatest player of the game of Go in the 20th century and of all time.-Biography:...
(Chinese: Wu Qingyuan), who scored an impressive 80% in these matches, and Minoru Kitani
Minoru Kitani
was one of the most celebrated professional Go players and teachers of the game of Go in the twentieth century in Japan.- Biography :He earned the nickname "the Prodigy" after winning a knockout tournament. He defeated eight opponents from the Kiseisha in a row during 1928. He played a celebrated...
, who dominated matches in the early 1930s. These two players are also recognized for their groundbreaking work on new opening theory
Go opening theory
In the game of Go, the term opening theory refers to concepts which underlie where, why, in what order, and in what shapes the first several moves are played...
(Shinfuseki
Shinfuseki
or new opening strategy was the change of attitude to go opening theory that set in strongly in Japan in 1933. It corresponds, a little later, to hypermodern play in chess, with the inversion that shinfuseki thought the center of the board had been unjustly underemphasised.In the 1930s, a group of...
).
For much of the 20th century, Go continued to be dominated by players trained in Japan. Notable names included Eio Sakata
Eio Sakata
was a professional 9-dan Japanese professional Go player.- Biography :Sakata became a professional Go player in 1935. His first title match was the Hon'inbō in 1951 when he challenged Hashimoto Utaro. At the time, Hon'inbō started the Kansai Ki-in, so Sakata was under pressure to win the title back...
, Rin Kaiho
Rin Kaiho
Rin Kaiho is a professional Go player.-Biography:Rin Kaiho was born in Shanghai, China. He was a student of Go Seigen when Go brought him to Japan in 1952. He was a promising player who won his first title at the age of 23, the Meijin. He is also part of the 1200 win group...
(born in China), Masao Kato
Masao Kato
- Titles and runners-up :Ranks #4 in total amount of titles in Japan.-Books:*Kato's Attack and Kill ISBN 4-87187-027-2*The Chinese Opening ISBN 4-906574-33-5-External links:...
, Koichi Kobayashi
Koichi Kobayashi
is a Go player.- Biography :Koichi Kobayashi was born in Asahikawa, Japan. He was one of the more famous disciples of the legendary Minoru Kitani; he studied along with Cho Chikun, Masao Kato, Yoshio Ishida, and Masaki Takemiya. He would go on and marry the daughter of his teacher, Reiko Kitani , a...
and Cho Chikun
Cho Chikun
Cho Chihun 25th Honinbo Honorary Meijin is a professional Go player. His total title tally of 71 titles is the most in the history of the Japanese Nihon Ki-in. Cho is the only player to hold the top three titles—Kisei, Meijin, and Honinbo—simultaneously which he did for 3 years in a row...
(born Cho Ch'i-hun, South Korea). Top Chinese and Korean talents often moved to Japan, because the level of play there was high and funding was more lavish. One of the first Korean players to do so was Cho Namchul, who studied in the Kitani Dojo 1937–1944. After his return to Korea, the Hanguk Kiwon (Korea Baduk Association) was formed and caused the level of play in South Korea to rise significantly in the second half of the 20th century. In China, the game declined during the Cultural Revolution
Cultural Revolution
The Great Proletarian Cultural Revolution, commonly known as the Cultural Revolution , was a socio-political movement that took place in the People's Republic of China from 1966 through 1976...
(1966–1976) but quickly recovered in the last quarter of the 20th century, bringing Chinese players, such as Nie Weiping
Nie Weiping
Nie Weiping in Shen, Hebei, China) is a professional Go player.- Biography :Nie began learning Go at the age of nine and won the inaugural World Amateur Go Championship in 1979. Nie was given 9 dan rank in 1982. He became famous in the Go world after leading China to victory in the China-Japan...
and Ma Xiaochun
Ma Xiaochun
Ma Xiaochun is a Chinese professional Go player.- Biography :Ma was born in Zhejiang, China. He began playing Go at the age of nine and was awarded 7 dan rank in 1982. In 1983, Ma was promoted to 9 dan. He visited Japan in 1982 and later won the World Amateur Go Championship in 1983...
, on par with their Japanese and Korean counterparts.
Lee Chang-ho
Lee Chang-ho is a South Korean professional Go player of 9-dan rank. He is regarded by many as one of the strongest modern Go players. He was a student of Cho Hunhyun 9-dan. He is the only player to have won all eight international competitions at least once.-Biography:He turned professional in...
, Cho Hunhyun
Cho Hunhyun
Cho Hunhyun is a Korean 9-dan professional Go player. Considered one of the greatest players of all-time, Cho reached professional level in Korea in 1962. Since then, Cho has amassed 150 professional titles, more than any player in the world. He once held all nine Korea titles simultaneously in 1980...
, Lee Sedol
Lee Sedol
Lee Sedol is a South Korean professional Go player of 9-dan rank.-Biography:Many regard Lee Sedol as one of the strongest players of all time. Lee was born in Korea in 1983 and studied at the Hanguk Kiwon. He ranks third in career titles with 37, behind Cho Hunhyun and Lee Chang-ho...
and Yoo Changhyuk
Yoo Changhyuk
Yoo Changhyuk is a professional Go player in South Korea.- Biography :Yoo Changhyuk was one of Korea's best Go players. Growing up without a teacher, Yoo became a professional in 1984 and was promoted to 9 dan in 1996...
dominated international Go and won an impressive number of titles. Several Chinese players also rose to the top in international Go, most notably Ma Xiaochun
Ma Xiaochun
Ma Xiaochun is a Chinese professional Go player.- Biography :Ma was born in Zhejiang, China. He began playing Go at the age of nine and was awarded 7 dan rank in 1982. In 1983, Ma was promoted to 9 dan. He visited Japan in 1982 and later won the World Amateur Go Championship in 1983...
, Chang Hao
Chang Hao
Chang Hao is a professional Go player. He is a 9 dan Go player from China. He is China's best player of the 1990s and one of the best in the world. Growing up he was a prodigy in China. He has won many titles, two of them international titles. He is best friends with Lee Chang-ho, whom he most...
and Gu Li
Gu Li
Gu Li is a Chinese professional Go player.- Biography :Gu Li is currently the #1 ranked Chinese player by the Zhongguo Qiyuan. He became a pro in 1994 when he was only 12. In 2006, he won the 10th LG Cup and became the youngest Chinese player to ever win a major international title; as a result,...
. , Japan lags behind in the international Go scene.
Historically, as with most sports and games, more men than women have played Go. Special tournaments for women exist, but until recently, men and women did not compete together at the highest levels; however, the creation of new, open tournaments and the rise of strong female players, most notably Rui Naiwei
Rui Naiwei
Rui Naiwei is a Chinese professional Go player, now active in South Korea...
, have in recent years highlighted the strength and competitiveness of emerging female players.
The level in other countries has traditionally been much lower, except for some players who had preparatory professional training in Asia.Kaku Takagawa
Kaku Takagawa
, also known as , was one of the most successful professional Go players of the twentieth century.- Biography :Kaku Takagawa won the Honinbō title nine times in a row, from 1952 to 1960, and was subsequently awarded the permanent title of Honorary Honinbo. He then chose Shukaku as his Honinbō name....
toured Europe around 1970, and reported (Go Review) a general standard of amateur 4 dan. This is a good amateur level but no more than might be found in ordinary Asian clubs. Published current European ratings would suggest around 100 players stronger than that, with very few European 7 dans. Knowledge of the game has been scant elsewhere up until the 20th century. A famous player of the 1920s was Edward Lasker
Edward Lasker
Edward Lasker was a leading German-American chess and Go player. He was awarded the title of International Master of chess by FIDE. Lasker was an engineer by profession, and an author.-Background:...
.European Go has been documented by Franco Pratesi, Eurogo (Florence 2003) in three volumes, up to 1920, 1920–1950, and 1950 and later. It was not until the 1950s that more than a few Western players took up the game as other than a passing interest. In 1978, Manfred Wimmer
Manfred Wimmer
Manfred Wimmer was the first Western professional go player. As of 2007, there have been fewer than a dozen professional go players born outside of Asia.Manfred Wimmer was born in Austria in 1944...
became the first Westerner to receive a professional player's certificate from an Asian professional Go association. In 2000, a Westerner, Michael Redmond, finally achieved the top rank awarded by an Asian Go association, 9 dan. In total, , only nine non-Asian Go players have ever achieved professional status in Asian associations.
Equipment
Laminate
A laminate is a material that can be constructed by uniting two or more layers of material together. The process of creating a laminate is lamination, which in common parlance refers to the placing of something between layers of plastic and gluing them with heat and/or pressure, usually with an...
d particle board
Particle board
Particle board, or particleboard , is an engineered wood product manufactured from wood particles, such as wood chips, sawmill shavings, or even saw dust, and a synthetic resin or other suitable binder, which is pressed and extruded...
, or wood boards with stones of plastic or glass. More expensive traditional materials are still used by many players. The most expensive Go sets have black stones carved from slate and white stones carved from translucent white shells.
Boards
The Go board (generally referred to by its Japanese name goban) typically measures between 45 centimetre in length (from one player's side to the other) and 42 centimetre in width. Chinese boards are slightly larger, as a traditional Chinese Go stone is slightly larger to match. The board is not square; there is a 15:14 ratio in length to width, because with a perfectly square board, from the player's viewing angle the perspective creates a foreshortening of the board. The added length compensates for this. There are two main types of boards: a table board similar in most respects to other game boards like that used for chess, and a floor board, which is its own free-standing table and at which the players sit.The traditional Japanese goban is between 10 centimetre thick and has legs; it sits on the floor (see picture to right). It is preferably made from the rare golden-tinged Kaya
Torreya nucifera
Torreya nucifera is a slow-growing, coniferous tree native to southern Japan and to South Korea's Jeju Island. It is also called ' or Japanese nutmeg-yew.-Description:It grows to 15-25 m tall with a trunk up to 1.5 m diameter...
tree (Torreya nucifera), with the very best made from Kaya trees up to 700 years old. More recently, the related California Torreya
Torreya californica
Torreya californica is species of conifer endemic to California, occurring in the Pacific Coast Ranges and the foothills of the Sierra Nevada...
(Torreya californica) has been prized for its light color and pale rings as well as its reduced expense and more readily available stock. The natural resources of Japan have been unable to keep up with the enormous demand for the slow-growing Kaya trees; both T. nucifera and T. californica take many hundreds of years to grow to the necessary size, and they are now extremely rare, raising the price of such equipment tremendously. As Kaya trees are a protected species in Japan, they cannot be harvested until they have died. Thus, an old-growth, floor-standing Kaya goban can easily cost in excess of US$10,000 with the highest-quality examples costing more than $60,000.
Other, less expensive woods often used to make quality table boards in both Chinese and Japanese dimensions include Hiba
Thujopsis
Thujopsis is a conifer in the cypress family , the sole member of the genus being Thujopsis dolabrata. It is endemic to Japan, where it is named asunaro . It is similar to the closely related genus Thuja , differing in the broader, thicker leaves and thick cones...
(Thujopsis dolabrata), Katsura (Cercidiphyllum japonicum), Kauri
Agathis
The genus Agathis, commonly known as kauri or dammar, is a relatively small genus of 21 species of evergreen tree. The genus is part of the ancient Araucariaceae family of conifers, a group once widespread during the Jurassic period, but now largely restricted to the Southern Hemisphere except for...
(Agathis), and Shin Kaya (various varieties of spruce
Spruce
A spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...
, commonly from Alaska, Siberia and China's Yunnan Province). So-called Shin Kaya is a potentially confusing merchant's term: shin means "new", and thus shin kaya is best translated "faux kaya", because the woods so described are biologically unrelated to Kaya.
Stones
A full set of Go stones (goishi) usually contains 181 black stones and 180 white ones; a 19×19 grid has 361 points, so there are enough stones to cover the board, and Black gets the extra odd stone because that player goes first.Traditional Japanese stones are double-convex, and made of clam
Clam
The word "clam" can be applied to freshwater mussels, and other freshwater bivalves, as well as marine bivalves.In the United States, "clam" can be used in several different ways: one, as a general term covering all bivalve molluscs...
shell (white) and slate
Slate
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. The result is a foliated rock in which the foliation may not correspond to the original sedimentary layering...
(black). The classic slate is nachiguro stone mined in Wakayama Prefecture
Wakayama Prefecture
is a prefecture of Japan located on the Kii Peninsula in the Kansai region on Honshū island. The capital is the city of Wakayama.- History :Present-day Wakayama is mostly the western part of the province of Kii.- 1953 Wakayama Prefecture flood disaster :...
and the clamshell from the Hamaguri clam; however, due to a scarcity in the Japanese supply of this clam, the stones are most often made of shells harvested from Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. Historically, the most prized stones were made of jade
Jade
Jade is an ornamental stone.The term jade is applied to two different metamorphic rocks that are made up of different silicate minerals:...
, often given to the reigning emperor as a gift.
In China, the game is traditionally played with single-convex stones made of a composite called Yunzi
Yunzi
Yunzi refer to special weiqi pieces manufactured in the Chinese province of Yunnan. At various times in history they have also been termed yunbian and yunyaozi...
. The material comes from Yunnan Province and is made by sintering
Sintering
Sintering is a method used to create objects from powders. It is based on atomic diffusion. Diffusion occurs in any material above absolute zero, but it occurs much faster at higher temperatures. In most sintering processes, the powdered material is held in a mold and then heated to a temperature...
a proprietary and trade-secret mixture of mineral compounds. This process dates to the Tang Dynasty and, after the knowledge was lost in the 1920s during the Chinese Civil War
Chinese Civil War
The Chinese Civil War was a civil war fought between the Kuomintang , the governing party of the Republic of China, and the Communist Party of China , for the control of China which eventually led to China's division into two Chinas, Republic of China and People's Republic of...
, was rediscovered in the 1960s by the now state-run Yunzi company. The material is praised for its colors, its pleasing sound as compared to glass or to synthetics such as melamine
Melamine
Melamine is an organic base and a trimer of cyanamide, with a 1,3,5-triazine skeleton. Like cyanamide, it contains 66% nitrogen by mass and, if mixed with resins, has fire retardant properties due to its release of nitrogen gas when burned or charred, and has several other industrial uses....
, and its lower cost as opposed to other materials such as slate/shell. The term "yunzi" can also refer to a single-convex stone made of any material; however, most English-language Go suppliers will specify Yunzi as a material and single-convex as a shape to avoid confusion, as stones made of Yunzi are also available in double-convex while synthetic stones can be either shape.
Traditional stones are made so that black stones are slightly larger in diameter than white; this is to compensate for the optical illusion created by contrasting colors that would make equal-sized white stones appear larger on the board than black stones.See Overshoot
Overshoot (typography)
In typeface design, the overshoot of a round or pointed letter is the degree to which it extends higher or lower than a comparably sized "flat" letter , to achieve an optical effect of being the same size....
in Western typography for similar subtle adjustment to create a uniform appearance.
Bowls
The bowls for the stones are shaped like a flattened sphere with a level underside. The lid is loose fitting and upturned before play to receive stones captured during the game. Chinese bowls are slightly larger, and a little more rounded, a style known generally as Go Seigen; Japanese Kitani bowls tend to have a shape closer to that of the bowl of a snifterSnifter
A snifter — also called a balloon — is a type of stemware, a short-stemmed glass whose vessel has a wide bottom and a relatively narrow top. It is mostly used to serve aged brown spirits such as brandy and whisky...
glass, such as for brandy
Brandy
Brandy is a spirit produced by distilling wine. Brandy generally contains 35%–60% alcohol by volume and is typically taken as an after-dinner drink...
. The bowls are usually made of turned wood. Rosewood
Rosewood
Rosewood refers to any of a number of richly hued timbers, often brownish with darker veining, but found in many different hues. All rosewoods are strong and heavy, taking an excellent polish, being suitable for guitars, marimbas, turnery , handles, furniture, luxury flooring, etc.In general,...
is the traditional material for Japanese bowls, but is very expensive; wood from the Chinese jujube
Jujube
Ziziphus zizyphus , commonly called jujube , red date, Chinese date, Korean date, or Indian date is a species of Ziziphus in the buckthorn family Rhamnaceae, used primarily as a fruiting shade tree.-Distribution:Its precise natural distribution is uncertain due to extensive cultivation,...
date tree, which has a lighter color (it is often stained) and slightly more visible grain pattern, is a common substitute for rosewood, and traditional for Go Seigen-style bowls. Other traditional materials used for making Chinese bowls include lacquer
Lacquer
In a general sense, lacquer is a somewhat imprecise term for a clear or coloured varnish that dries by solvent evaporation and often a curing process as well that produces a hard, durable finish, in any sheen level from ultra matte to high gloss and that can be further polished as required...
ed wood, ceramics, stone and woven straw or rattan
Rattan
Rattan is the name for the roughly 600 species of palms in the tribe Calameae, native to tropical regions of Africa, Asia and Australasia.- Structure :...
. The names of the bowl shapes, Go Seigen and Kitani, pay homage to two 20th-century professional Go players by the same names, of Chinese and Japanese nationality, respectively, who are referred to as the "Fathers of modern Go".
Modern and low-cost alternatives
In clubs and at tournaments, where large numbers of sets must be purchased and maintained by one organization, expensive traditional sets are not usually used. For these situations, table boards are usually used instead of floor boards, and are either made of a lower-cost wood such as spruce or bamboo, or are flexible mats made of vinylVinyl
A vinyl compound is any organic compound that contains a vinyl group ,which are derivatives of ethene, CH2=CH2, with one hydrogen atom replaced with some other group...
that can be rolled up. In such cases, the stones are usually made of glass, plastic or resin (such as melamine or Bakelite) rather than slate and shell. Bowls are often made of plastic or inexpensive wood.
Common "novice" Go sets are all-inclusive kits made of particle board or plywood
Plywood
Plywood is a type of manufactured timber made from thin sheets of wood veneer. It is one of the most widely used wood products. It is flexible, inexpensive, workable, re-usable, and can usually be locally manufactured...
, with plastic or glass stones, that either fold up to enclose the stone containers or have pull-out drawers to keep stones. In relative terms, these sets are inexpensive, costing US$20–$40 depending on component quality, and thus are popular with casual Go players. Magnetic sets are also available, either as portable travel sets or in larger sizes for educational purposes.
Playing technique and etiquette
Time control
A game of Go may be timed using a game clockGame clock
A game clock consists of two adjacent clocks and buttons to stop one clock while starting the other, such that the two component clocks never run simultaneously. Game clocks are used in two-player games where the players move in turn...
. Formal time controls were introduced into the professional game during the 1920s and were controversial. Adjournments and sealed moves began to be regulated in the 1930s. Go tournaments use a number of different time control systems. All common systems envisage a single main period of time for each player for the game, but they vary on the protocols for continuation (in overtime) after a player has finished that time allowance.Roughly, one has the time to play the game and then a little time to finish it off. Time-wasting tactics are possible in Go, so that sudden death systems, in which time runs out at a predetermined point however many plays are in the game, are relatively unpopular (in the West). The most widely used time control system is the so called byoyomi
Byoyomi
is an extended time control in two-player games, specifically Shogi and Go. The word is borrowed from Japanese; the term literally means "counting the seconds," or more generally, "countdown."...
Literally in Japanese byōyomi means 'reading of seconds'. system. The top professional Go matches have timekeepers so that the players do not have to press their own clocks.
Two widely used variants of the byoyomi system are:
- Standard byoyomi: After the main time is depleted, a player has a certain number of time periods (typically around thirty seconds). After each move, the number of full time periods that the player took (often zero) is subtracted. For example, if a player has three thirty-second time periods and takes thirty or more (but less than sixty) seconds to make a move, they lose one time period. With 60–89 seconds, they lose two time periods, and so on. If, however, they take less than thirty seconds, the timer simply resets without subtracting any periods. Using up the last period means that the player has lost on time.
- Canadian byoyomi: After using all of their main time, a player must make a certain number of moves within a certain period of time, such as twenty moves within five minutes.Typically, players stop the clock, and the player in overtime sets his/her clock for the desired interval, counts out the required number of stones and sets the remaining stones out of reach, so as not to become confused. If twenty moves are made in time, the timer is reset to five minutes again. If the time period expires without the required number of stones having been played, then the player has lost on time.In other words, Canadian byoyomi is essentially a standard chess-style time control, based on N moves in a time period T, imposed after a main period is used up. It is possible to decrease T, or increase N, as each overtime period expires; but systems with constant T and N, for example 20 plays in 5 minutes, are widely used.
Notation and recording games
Go games are recorded with a simple coordinate system. This is comparable to algebraic chess notationAlgebraic chess notation
Algebraic notation is a method for recording and describing the moves in a game of chess. It is now standard among all chess organizations and most books, magazines, and newspapers...
, except that Go stones do not move and thus require only one coordinate per turn. Coordinate systems include purely numerical (4-4 point), hybrid (K3), and purely alphabetical. The Smart Game Format
Smart Game Format
The Smart Game Format is a computer file format used for storing records of board games. Games currently supported are Amazons, Ataxx, Backgammon, Byte, Chase, Chess, DVONN, Exxit, Focus, Gess, GIPF, Go, Gobblet, Gomoku+Renju, Hex, Hive, Hnefatafl, Jungle, Kropki, Kuba, Lines of Action, Neutron,...
uses alphabetical coordinates internally, but most editors represent the board with hybrid coordinates as this reduces confusion. The Japanese word kifu
Kifu
Kifu is the Japanese term for a game record for a game of Go or shogi. Kifu is traditionally used to record games on a grid diagram, marking the plays on the points by numbers....
is sometimes used to refer to a game record.
Nature of the game
Combinatorial game theory
Combinatorial game theory is a branch of applied mathematics and theoretical computer science that studies sequential games with perfect information, that is, two-player games which have a position in which the players take turns changing in defined ways or moves to achieve a defined winning...
terms, Go is a zero sum, perfect-information
Perfect information
In game theory, perfect information describes the situation when a player has available the same information to determine all of the possible games as would be available at the end of the game....
, partisan
Partisan game
In combinatorial game theory, a game is partisan or partizan if it is not impartial. That is, some moves are available to one player and not to the other.Most games are partisan; for example, in chess, only one player can move the white pieces....
, deterministic
Deterministic system (mathematics)
In mathematics, a deterministic system is a system in which no randomness is involved in the development of future states of the system. A deterministic model will thus always produce the same output from a given starting condition or initial state.-Examples:...
strategy game
Strategy game
A strategy game or strategic game is a game in which the players' uncoerced, and often autonomous decision-making skills have a high significance in determining the outcome...
, putting it in the same class as chess, checkers (draughts) and Reversi
Reversi
Reversi is a board game involving abstract strategy and played by two players on a board with 8 rows and 8 columns and a set of distinct pieces for each side. Pieces typically are disks with a light and a dark face, each face belonging to one player...
(Othello); however it differs from these in its game play. Although the rules are simple, the practical strategy is extremely complex.
The game emphasizes the importance of balance on multiple levels and has internal tensions. To secure an area of the board, it is good to play moves close together; however, to cover the largest area, one needs to spread out, perhaps leaving weaknesses that can be exploited. Playing too low (close to the edge) secures insufficient territory and influence, yet playing too high (far from the edge) allows the opponent to invade.
It has been claimed that Go is the most complex game in the world due to its vast number of variations in individual games. Its large board and lack of restrictions allow great scope in strategy and expression of players' individuality. Decisions in one part of the board may be influenced by an apparently unrelated situation in a distant part of the board. Plays made early in the game can shape the nature of conflict a hundred moves later.
The game complexity
Game complexity
Combinatorial game theory has several ways of measuring game complexity. This article describes five of them: state-space complexity, game tree size, decision complexity, game-tree complexity, and computational complexity.-Measures of game complexity:...
of Go is such that describing even elementary strategy fills many introductory books. In fact, numerical estimates show that the number of possible games of Go far exceeds the number of atoms in the known universe.The number of board positions is at most 3361 (about 10172) since each position can be white, black, or vacant. Ignoring (illegal) suicide moves, there are at least 361! games (about 10768) since every permutation of the board positions corresponds to a game. See Go and mathematics
Go and mathematics
The game of Go is one of the most popular games in the world and is on par with games such as chess, in any of its Western or Asian variants, in terms of game theory and as an intellectual activity...
for more details, which includes much larger estimates.
Software players
Go poses a daunting challenge to computer programmers. The strongest computer chess programs defeat the best human players (for example, the Deep Fritz program, running on a laptop, beat reigning world champion Vladimir KramnikVladimir Kramnik
Vladimir Borisovich Kramnik is a Russian chess grandmaster. He was the Classical World Chess Champion from 2000 to 2006, and the undisputed World Chess Champion from 2006 to 2007...
without losing a single game in 2006). The best Go programs manage to reach amateur dan level. On the small 9×9 board, the computer fares better, and some programs now win a fraction of their 9×9 games against professional players. Many in the field of artificial intelligence
Artificial intelligence
Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...
consider Go to require more elements that mimic human thought than chess
Chess
Chess is a two-player board game played on a chessboard, a square-checkered board with 64 squares arranged in an eight-by-eight grid. It is one of the world's most popular games, played by millions of people worldwide at home, in clubs, online, by correspondence, and in tournaments.Each player...
.
- The number of spaces on the board is much larger (over five times the spaces on a chess board—361 vs. 64). On most turns there are many more possible moves in Go than in chess. Throughout most of the game, the number of legal moves stays at around 150–250 per turn, and rarely goes below 50 (in chess, the average number of moves is 37). Because an exhaustive computer program for Go must calculate and compare every possible legal move in each plyPly (game theory)In two-player sequential games, a ply refers to one turn taken by one of the players. The word is used to clarify what is meant when one might otherwise say "turn"....
(player turn), its ability to calculate the best plays is sharply reduced when there are a large number of possible moves. Most computer game algorithms, such as those for chess, compute several moves in advance. Given an average of 200 available moves through most of the game, for a computer to calculate its next move by exhaustively anticipating the next four moves of each possible play (two of its own and two of its opponent's), it would have to consider more than 320 billion (3.2) possible combinations. To exhaustively calculate the next eight moves, would require computing 512 quintillion (5.12) possible combinations. , the most powerful supercomputer in the world, IBM's "Roadrunner" distributed cluster, can sustain 1.02 petaflopsFLOPSIn computing, FLOPS is a measure of a computer's performance, especially in fields of scientific calculations that make heavy use of floating-point calculations, similar to the older, simpler, instructions per second...
. At this rate, even given an exceedingly low estimate of 10 flops required to assess the value of one play of a stone, Roadrunner would require 138 hours, more than five days, to assess all possible combinations of the next eight moves in order to make a single play. - Unlike chess and ReversiReversiReversi is a board game involving abstract strategy and played by two players on a board with 8 rows and 8 columns and a set of distinct pieces for each side. Pieces typically are disks with a light and a dark face, each face belonging to one player...
, the placement of a single stone in the initial phase can affect the play of the game hundreds of moves later. For a computer to have a real advantage over a human, it would have to predict this influence, and from the example above, it would be completely unworkable to attempt to exhaustively analyze the next hundred moves to predict what a stone's placement will do. - In capture-based games (such as chess), a position can often be evaluated relatively easily, such as by calculating who has a material advantage or more active pieces.While chess position evaluation is simpler than Go position evaluation, it is still more complicated than simply calculating material advantage or piece activity; pawn structure and king safety matter, as do the possibilities in further play. The complexity of the algorithm differs per engine. In Go, there is often no easy way to evaluate a position. The number of stones on the board (material advantage) is only a weak indicator of the strength of a position, and a territorial advantage (more empty points surrounded) for one player might be compensated by the opponent's strong positions and influence all over the board.
As an illustration, the greatest handicap normally given to a weaker opponent is 9 stones. It was not until August 2008 that a computer was able to win a game against a professional level player at this handicap. It was the Mogo program which scored said first victory in an exhibition game played during the US Go Congress.
Software assistance
Beyond programs that play Go, there is an abundance of software available to support players of the game. This includes programs that can be used to view or edit game records and diagrams, programs that allow the user to search for patterns in the games of strong players, and programs that allow users to play against each other over the Internet. Some web servers such as Peepo.com provide graphical aids like maps, to aid learning during play. These graphical aids may suggest possible next moves, indicate areas of influence, highlight vital stones under attack and mark stones in atari or about to be captured.There are several file formats used to store game records, the most popular of which is SGF, short for Smart Game Format
Smart Game Format
The Smart Game Format is a computer file format used for storing records of board games. Games currently supported are Amazons, Ataxx, Backgammon, Byte, Chase, Chess, DVONN, Exxit, Focus, Gess, GIPF, Go, Gobblet, Gomoku+Renju, Hex, Hive, Hnefatafl, Jungle, Kropki, Kuba, Lines of Action, Neutron,...
. Programs used for editing game records allow the user to record not only the moves, but also variations, commentary and further information on the game.Lists of such programs may be found at Sensei's Library or GoBase.
Electronic databases can be used to study life and death situations, joseki
Joseki
In Go, are studied sequences of moves in the corner areas of the Go board, for which the result is considered balanced for both black and white sides. Because games typically start with plays in the corners, players often try to use their understanding of joseki to gain local advantages in the...
, fuseki
Fuseki
Fuseki is the whole board opening in the game of Go.-Less systematic:Since each move is typically isolated and unforced , patterns for play on the whole board have seen much less systematic study than for Joseki, which are often contact moves which require specific and immediate responses...
and games by a particular player. Programs are available that give players pattern searching options, which allow players to research positions by searching for high-level games in which similar situations occur. Such software generally lists common follow-up moves that have been played by professionals and gives statistics on win/loss ratio in opening situations.
Internet-based Go servers
Internet Go server
An internet Go server is a server that allows players of the game of Go to play against other players online. The two fundamental types of Go server are real-time servers and turn-based servers.- History :...
allow access to competition with players all over the world, for real-time and turn-based games.Lists of Go servers are kept at Sensei's Library and the AGA website Such servers also allow easy access to professional teaching, with both teaching games and interactive game review being possible.The British Go Association provides a list of teaching services
Video games
is a 1987 Go video game that was released exclusively in Japan for the Family ComputerNintendo Entertainment System
The Nintendo Entertainment System is an 8-bit video game console that was released by Nintendo in North America during 1985, in Europe during 1986 and Australia in 1987...
.
Literature, television, and film
Apart from technical literature and study material, Go and its strategies have been the subject of several works of fiction, such as The Master of GoThe Master of Go
The Master of Go is a novel by the Nobel Prize-winning Japanese author Yasunari Kawabata, first published in serial form in 1951. Titled Meijin in its original Japanese, Kawabata considered it his finest work, although it is in contrast with his other works.-Plot introduction:It is a...
by Nobel prize
Nobel Prize
The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...
-winning author Yasunari Kawabata
Yasunari Kawabata
was a Japanese short story writer and novelist whose spare, lyrical, subtly-shaded prose works won him the Nobel Prize for Literature in 1968, the first Japanese author to receive the award...
A list of books can be found at Sensei's Library and The Girl Who Played Go by Shan Sa. Other books have used Go as a theme
Theme (literature)
A theme is a broad, message, or moral of a story. The message may be about life, society, or human nature. Themes often explore timeless and universal ideas and are almost always implied rather than stated explicitly. Along with plot, character,...
or minor plot device. For example, the 1979 novel Shibumi
Shibumi (novel)
Shibumi is a novel issued in 1979, written in English by Trevanian, a pseudonym of Rodney William Whitaker, an American academic who remained mysterious throughout most of his life...
by Trevanian
Trevanian
Rodney William Whitaker was an American film scholar and writer who wrote several successful novels under the pen name Trevanian. Whitaker also published works as Nicholas Seare, Beñat Le Cagot and Edoard Moran...
centers around the game and uses Go metaphors. Go, referred to as Weiqi, features prominently in the 1986 Eric Van Lustbader
Eric Van Lustbader
Eric Van Lustbader is a writer of thriller and fantasy novels.He is a graduate of New York's Stuyvesant High School and Columbia College, with a degree in Sociology, and is a second-level Reiki master.-The Pearl Saga:...
novel Jian.
Similarly, Go has been used as a subject or plot device in film, such as π
Pi (film)
Pi, also titled ,WorldCat gives the title as [Pi] and provides a note which states, "Title is the mathematical symbol for Pi." . Amazon gives the title as Pi with no notation concerning the math symbol . is a 1998 American psychological thriller film written and directed by Darren Aronofsky...
, A Beautiful Mind
A Beautiful Mind (film)
A Beautiful Mind is a 2001 American drama film based on the life of John Nash, a Nobel Laureate in Economics. The film was directed by Ron Howard and written by Akiva Goldsman. It was inspired by a bestselling, Pulitzer Prize-nominated 1998 book of the same name by Sylvia Nasar...
and Tron: Legacy. Also in The Go Master
The Go Master
The Go Master is a 2006 biopic by director Tian Zhuangzhuang of the renowned twentieth century Go master Wu Qingyuan, better known by his adopted Japanese name of Go Seigen...
, a biopic of Go professional Go Seigen
Go Seigen
Wu Qingyuan , generally known in the West by his Japanese name Go Seigen, is considered by many players to be the greatest player of the game of Go in the 20th century and of all time.-Biography:...
.A list of films can de found at the EGF Internet Go Filmography In King Hu
King Hu
King Hu was a Hong Kong- and Taiwan-based Chinese film director whose Wuxia films brought Chinese cinema to new technical and artistic heights. His films Come Drink with Me , Dragon Gate Inn and A Touch of Zen inaugurated a new generation of wuxia films in the late 1960s...
's wuxia
Wuxia
Wuxia is a broad genre of Chinese fiction concerning the adventures of martial artists. Although wuxia is traditionally a form of literature, its popularity has caused it to spread to diverse art forms like Chinese opera, manhua , films, television series, and video games...
film The Valiant Ones, the characters are color-coded as Go pieces (black or other dark shades for the Chinese, white for the Japanese invaders), Go boards and stones are used by the characters to keep track of soldiers prior to battle, and the battles themselves are structured like a game of Go. Go is used as a device for criminal profiling in the pilot episode of Criminal Minds
Criminal Minds
Criminal Minds is an American police procedural drama that premiered September 22, 2005, on CBS. The series follows a team of profilers from the FBI's Behavioral Analysis Unit based in Quantico, Virginia. The BAU is part of the FBI National Center for the Analysis of Violent Crime...
, "Extreme Aggressor".
In the television series Andromeda
Andromeda (TV series)
Andromeda is a Canadian-American science fiction television series, based on unused material by the late Star Trek creator Gene Roddenberry, developed by Robert Hewitt Wolfe, and produced by Roddenberry's widow, Majel Barrett Roddenberry. It starred Kevin Sorbo as High Guard Captain Dylan Hunt...
, flashbacks revealed that Captain Hunt used to play Go with his first officer, Gaheris Rhade. Hunt once caught Rhade cheating at the game by removing some of Hunt's stones when Hunt wasn't looking. Rhade's explanation for his cheating--that losing at a competition would call into question the quality of his genes, which would be a horrible outcome for a Nietzschean--was partially intended as a warning to Hunt that Rhade would later betray him.
Of particular note is the manga
Manga
Manga is the Japanese word for "comics" and consists of comics and print cartoons . In the West, the term "manga" has been appropriated to refer specifically to comics created in Japan, or by Japanese authors, in the Japanese language and conforming to the style developed in Japan in the late 19th...
(Japanese comic book) and anime
Anime
is the Japanese abbreviated pronunciation of "animation". The definition sometimes changes depending on the context. In English-speaking countries, the term most commonly refers to Japanese animated cartoons....
series Hikaru no Go
Hikaru no Go
is a manga series, a coming of age story based on the board game Go written by Yumi Hotta and illustrated by Takeshi Obata with an anime adaptation. The production of the series' Go games was supervised by Go professional Yukari Umezawa...
, released in Japan in 1998, which had a large impact in popularizing Go among young players, both in Japan and—as translations were released—abroad.
The video game company Atari was named after a Go term. Atari's founder Nolan Bushnell was quoted as saying: "In Go, when you are about to capture an opponent's piece, you politely warn them 'Atari' [check]. I felt that was a good aggressive name for a company."
Go has appeared in American films with great rarity. In Heaven Knows, Mr. Allison
Heaven Knows, Mr. Allison
Heaven Knows, Mr. Allison is a 1957 CinemaScope film which tells the story of two people stranded on an island in the Pacific Ocean during World War II....
, Japanese officers are seen playing Go, and Sister Angela tells Corporal Allison (incorrectly) that the purpose of the game is to capture your opponent's stones. In Heathers
Heathers
Heathers is a 1989 black comedy film starring Winona Ryder, Christian Slater and Shannen Doherty. The film portrays four girls in a trend-setting clique at a fictional Ohio high school...
, Veronica has a Go board in her bedroom. (The board is not visible in the cropped TV version.) In Tron: Legacy, Flynn plays Go. It is believed that Stanley Kubrick
Stanley Kubrick
Stanley Kubrick was an American film director, writer, producer, and photographer who lived in England during most of the last four decades of his career...
wanted HAL 9000
HAL 9000
HAL 9000 is the antagonist in Arthur C. Clarke's science fiction Space Odyssey saga. HAL is an artificial intelligence that interacts with the astronaut crew of the Discovery One spacecraft, usually represented as a red television-camera eye found throughout the ship...
to play Go, but chess was used instead. Kubrick was an experienced chess player, so he may have found Go more mysterious. In the television series Arrested Development characters Maebe and Anyang are seen playing Go in the concluding minute of the final episode of the first season, "Let 'Em Eat Cake
Let 'Em Eat Cake
Let 'Em Eat Cake is a Broadway musical that opened October 21, 1933 at the Imperial Theatre, New York, USA and ran for 89 performances. It had music by George Gershwin, lyrics by Ira Gershwin, and book by George S. Kaufman and Morrie Ryskind. The cast included William Gaxton, Victor Moore, Philip...
."
Psychology
A 2004 review of literature by Gobet, de Voogt & Retschitzki shows that relatively little scientific research has been carried out on the psychologyPsychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
of Go, compared with other traditional board games such as chess and Mancala
Mancala
Mancala is a family of board games played around the world, sometimes called "sowing" games, or "count-and-capture" games, which describes the game-play. Mancala games play a role in many African and some Asian societies comparable to that of chess in the West, or the game of Go in Eastern Asia...
. Computer Go research has shown that given the large search tree, knowledge and pattern recognition are more important in Go than in other strategy games, such as chess. A study of the effects of age on Go-playing has shown that mental decline is milder with strong players than with weaker players. According to the review of Gobet and colleagues, the pattern of brain activity observed with techniques such as PET
Positron emission tomography
Positron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...
and fMRI
Functional magnetic resonance imaging
Functional magnetic resonance imaging or functional MRI is a type of specialized MRI scan used to measure the hemodynamic response related to neural activity in the brain or spinal cord of humans or other animals. It is one of the most recently developed forms of neuroimaging...
does not show large differences between Go and chess. On the other hand, a study by Xiangchuan Chen et al. showed greater activation in the right hemisphere among Go players than among chess players. There is some evidence to suggest a correlation between playing board games and reduced risk of Alzheimer's disease
Alzheimer's disease
Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...
and dementia
Dementia
Dementia is a serious loss of cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging...
.
See also
- Go at the 2010 Asian GamesGo at the 2010 Asian GamesA Weiqi tournament was held at the 2010 Asian Games in Guangzhou for the first time at an Asiad. The three events in the competition - men's team, women's team and mixed doubles — were held between 20 and 26 November 2010 at the Guangzhou Chess Institute....
- Go opening strategyGo opening strategyGo opening strategy is the strategy applied in the game of go, in the early part of the game. On the traditional 19×19 board the opening phase of the game usually lasts between 15 and 40 plies.There are some conventional divisions that are applied...
- Go proverbGo proverbGo proverbs are traditional proverbs relating to the game of Go, generally used to help one find good moves in various situations during a game. They are generalisations and thus a particular proverb will have specific situations where it is not applicable. Knowing when a proverb is inapplicable is...
s - Go variantsGo variantsThere are many variations on the basic game of Go. Some are ancient digressions, while other are modern deviations. They are often to be found as side events at tournaments, for instance the U.S...
and Games played with Go equipmentGames played with Go equipmentMany games can be played with Go equipment: a supply of white and black stones and a board with 19×19 intersections, other than Go and many more can be played with minor modification.... - List of Go organizations
- List of professional Go tournaments
Further reading
Introductory books:- Bradley, Milton N. Go for Kids, Yutopian Enterprises, Santa Monica, 2001 ISBN 978-1-889554-74-7.
- Cho, ChikunCho ChikunCho Chihun 25th Honinbo Honorary Meijin is a professional Go player. His total title tally of 71 titles is the most in the history of the Japanese Nihon Ki-in. Cho is the only player to hold the top three titles—Kisei, Meijin, and Honinbo—simultaneously which he did for 3 years in a row...
. Go: A Complete Introduction to the Game, Kiseido Publishers, Tokyo, 1997, ISBN 978-4-906574-50-6. - Cobb, William. The Book of Go, Sterling PublishersSterling PublishingSterling Publishing Company, Inc. is a publisher of nonfiction titles, with more than 5,000 books in print. Founded in 1949, it publishes a wide range of nonfiction and illustrated titles in categories which include art, biography/autobiography, body/mind/spirit, crafts, culinary, do-it-yourself,...
, 2002, ISBN 978-0-8069-2729-9. - Iwamoto, KaoruKaoru Iwamoto,also known as Honinbo Kunwa, was a Japanese professional Go player who achieved the rank of 9-dan.- Biography :Iwamoto was born in Masuda of the Shimane prefecture, Japan.During his childhood he spent several years in Busan, Korea ,...
. Go for Beginners, Pantheon, New York, 1977, ISBN 978-0-394-73331-9. - Kim, JaniceJanice KimJanice Kim is a professional go player, author, and business owner. She was born in Illinois in 1969 , and grew up in New Mexico. As a teenager, she studied go in Korea under Jeong Soo-hyon . She represented the US in the first World Youth Go Championship in 1984, placing third; in 1986 she...
, and Jeong Soo-hyun. Learn to Play Go series, five volumes: Good Move Press, Sheboygan, Wisconsin, second edition, 1997. ISBN 0-9644796-1-3. - Matthews, Charles. Teach Yourself Go, McGraw-HillMcGraw-HillThe McGraw-Hill Companies, Inc., is a publicly traded corporation headquartered in Rockefeller Center in New York City. Its primary areas of business are financial, education, publishing, broadcasting, and business services...
, 2004, ISBN 978-0-07-142977-1. - Shotwell, Peter. Go! More than a Game, Tuttle PublishingTuttle PublishingTuttle Publishing, originally the Charles E. Tuttle Company, is a book publishing company that includes Tuttle, Periplus Editions, and Journey Editions...
, Boston, 2003. ISBN 0-8048-3475-X.
Historical interest:
External links
- International Go Federation (IGF), at intergofed.org
- European Go Federation (EGF), at eurogofed.org
- American Go Association (AGA), at usgo.org
- The Nihon Ki-in (Japan Go Association), at nihonkiin.or.jp
- Go in Print, list and reviews of English Go books, at usgo.org
- Go Servers, list of servers for playing on-line at Sensei's Library, at senseis.xmp.net
- Goproblems.com, open database of interactive Go problems, at goproblems.com
- Go Game Guru, frequently updated site where you can learn Go, study Go and read Go news