Capturing race
Encyclopedia
In the game of go
, a capturing race (Japanese language
semeai) is a tactical situation created in positions when both players have groups striving to capture each other, in some closely delimited area of the board. Typically it is not possible for each side to create a safe group with two eyes.
One common outcome is that one group is captured, resolving the race. In the most simple situations it is possible to predict this result, by counting the liberties on each group: if for example there are four liberties each, the advantage will lie with the player able to play first, while if one side has four liberties and the other five, the result is already decided and neither player will continue (the player who is behind will normally leave the area alone, seeing it as a future source of ko threats).
There are numerous other possible outcomes, for example a seki
, a ko of a direct or indirect nature, and (rather rarely) more exotic types of repeating situation such as triple ko or chosei. In the more orthodox races some theory is available to help understand the status as far as liberties goes, when these are not completely WYSIWYG
; but such theories are not so far able to give an exhaustive description of all capturing races.
Go (board game)
Go , is an ancient board game for two players that originated in China more than 2,000 years ago...
, a capturing race (Japanese language
Japanese language
is a language spoken by over 130 million people in Japan and in Japanese emigrant communities. It is a member of the Japonic language family, which has a number of proposed relationships with other languages, none of which has gained wide acceptance among historical linguists .Japanese is an...
semeai) is a tactical situation created in positions when both players have groups striving to capture each other, in some closely delimited area of the board. Typically it is not possible for each side to create a safe group with two eyes.
One common outcome is that one group is captured, resolving the race. In the most simple situations it is possible to predict this result, by counting the liberties on each group: if for example there are four liberties each, the advantage will lie with the player able to play first, while if one side has four liberties and the other five, the result is already decided and neither player will continue (the player who is behind will normally leave the area alone, seeing it as a future source of ko threats).
There are numerous other possible outcomes, for example a seki
Seki
Seki can refer to:* Seki, Gifu, a town in Japan* Seki Takakazu, a 17th-century Japanese mathematician* Seki , a term in the game of Go* Lieutenant Yukio Seki, the pilot who led the first attack of a Kamikaze unit...
, a ko of a direct or indirect nature, and (rather rarely) more exotic types of repeating situation such as triple ko or chosei. In the more orthodox races some theory is available to help understand the status as far as liberties goes, when these are not completely WYSIWYG
WYSIWYG
WYSIWYG is an acronym for What You See Is What You Get. The term is used in computing to describe a system in which content displayed onscreen during editing appears in a form closely corresponding to its appearance when printed or displayed as a finished product...
; but such theories are not so far able to give an exhaustive description of all capturing races.
Example
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| This problem (Difficulty: 5 dan) begins with B1. Can white save his stones and "make life"? This kind of problem is called a semeai; where one is in a "race" to capture the opponent first... | W2 is the correct move here. Black approaches with B3, and white protects with W4. Note that both B and W groups have four liberties, and now it's Black's move... | After the next few moves, the situation becomes clearer. Despite black's best responses, the five white stones have one more liberty (the one below move 9) than black does. If it's not clear how white survives, see the next image for detail... | After W10, B11, W12, the black stones are in atari. When eventually black plays 13 (as a ko threat), white can capture the four black stones. |
See also
- International Go FederationInternational Go FederationThe 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:...