Fifty move rule
Encyclopedia
The fifty-move rule in chess
states that a player can claim a draw
if no capture has been made and no pawn
has been moved in the last fifty consecutive moves (fifty moves by each side). The intended reason for the rule is so that a player with no chance to win cannot be obstinate and play on indefinitely , or seek a win purely due to an opponent's fatigue. All of the basic checkmate
s can be accomplished in well under fifty moves.
In the 20th century it was discovered that some positions of certain endgames can only be won in more than fifty moves (without a capture or a pawn move). The rule was changed to include certain exceptions in which one hundred moves were allowed with particular material combinations. However, more and more exceptions were discovered and in 1992 FIDE abolished all such exceptions and reinstated the strict fifty-move rule.
laws of chess is rule 9.3:
Naturally, if a player writes down his next move as under (a) above, it must not be a pawn move or a capture for a valid claim. Additionally, a claim does not have to be made at the first opportunity – it can be made any time when there were no captures or pawn moves in the last fifty moves.
A game is not automatically declared a draw under the fifty-move rule – the draw must be claimed by a player on his turn to move. Therefore a game can continue beyond a point where a draw could be claimed under the rule. Theoretically, a game could continue indefinitely this way; but in practice, when a draw under the fifty-move rule can be claimed, one of the players is usually happy to claim it .
Games drawn under the fifty-move rule before the endgame are rare. One example is the game Filipowicz versus Smederevac, Polanica Zdrój 1966, which was drawn on move 70 without any captures having been made in the whole game and with the last pawn being moved on move 20.
In this 1995 game between Jan Timman
and Christopher Lutz
, an endgame with a rook and bishop versus a rook occurred. White is striving for the winning Philidor position
while Black is employing the drawing Cochrane Defense and the "second-rank defense" (see rook and bishop versus rook endgame). Black was defending well in the difficult defense and could have claimed a draw on the 119th move. Lutz notes that he claimed a draw on move 121, ironically when making a move that gets into a losing position .
A draw by the fifty-move rule could have been claimed after Black's 112th move in a 1991 game between Anatoly Karpov
and Garry Kasparov
, but neither player claimed it. The last capture occurred on White's 63rd move (and the last pawn move occurred before that). By FIDE rule 9.3 part (a), White could have written his 113th move (which wouldn't have been a capture or pawn move) on his scoresheet and claimed a draw. By FIDE rule 9.3 part (b), after White's 113th move, either player could have claimed a draw on their turn to move, without having to write down their next move. Instead, the game continued a few more moves:
The players agreed to a draw
at this point because after 115. Kxf6 the position is a stalemate
. If 115. Ke8 Rxf5 116. Nxf5, and the position is clearly drawn because the two knights cannot force checkmate
(see two knights endgame).
An unusual occurrence happened in a game in the 2001 Armenian Championship
between Smbat Lputian
(who won the championship) and Gevorg Haroutjunian. The last pawn move was on White's 86th move and no captures occurred after it. (The game was a theoretical draw from before here until Black's 141st move.) Black could have claimed a draw after White's 136th move (or any of the subsequent moves). Instead, the game continued and Black resigned on his 142nd move – even though the right to claim a draw was still in effect .
's analysis of the two knights endgame as well as the endgame of a rook and bishop versus a rook. The rules of chess were revised several times to admit exceptions to the fifty-move rule for certain specific situations. Early on, the fifty-move rule applied to tournament games but not to match games .
During the time periods when the fifty-move rule admitted exceptions, there were a number of revisions. In 1928 FIDE enacted rules that if an endgame theoretically requires more than fifty moves to force checkmate, twice that number of moves were allowed. For instance, in the rook and bishop versus rook endgame, 132 moves were allowed, since it was twice the 66 moves that were thought to be required at that time . (The actual maximal number of moves needed is 59.) . In 1952 FIDE revised the law, allowing for one hundred moves in such positions but requiring that players agree to an extension for these positions before the first move is made. This was still in effect in 1960. The positions were not specified in the rules, to allow for the possibility of more positions requiring more than fifty moves to be discovered (which is what happened). These positions were understood to require more than fifty moves:
Article 12.4 of the 1965 FIDE rules states:
In 1984 the rule was modified and it became Article 10.9. Now one hundred moves were explicitly specified and the positions above were listed in the rule . (The language about the positions and number of moves having to be specified in advance of the game was dropped.) Ken Thompson
's investigations in the 1980s using the Belle
chess computer discovered numerous endgames winnable in more than fifty moves. However, these often involved seemingly random moves that defied human comprehension or analysis, in situations that would hardly ever occur in real gameplay. In 1989 the rule (still Article 10.9) was changed to 75 moves, and the listed positions were:
The rule was changed to allow for fifty moves in all positions. Some sources say that the 1989 rule was in effect only a "year or so" or a "few years" , but one source of the 1992 rules gives the pre-1984 wording: "... increased for certain positions if it was announced in advance" . By 2001 the rule was Article 9.3 and allowed fifty moves for all positions .
Research in the field of how many moves are required to win certain endgames has continued. Exhaustive retrograde analysis
using faster computers to build endgame tablebase
s has uncovered many more such endgames, often of previously unsuspected length. , the record is 517 moves (assuming optimal play by both sides) to make a piece capture or exchange that achieves a simpler and more obviously winnable sub-endgame, for a particular position involving a queen and knight versus a rook, bishop, and knight.
Many of the longest games on record involve the rook and bishop versus rook endgame, when the rule for more moves was in effect. (See pawnless chess endgame and rook and bishop versus rook endgame.)
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...
states that a player can claim a draw
Draw (chess)
In chess, a draw is when a game ends in a tie. It is one of the possible outcomes of a game, along with a win for White and a win for Black . Usually, in tournaments a draw is worth a half point to each player, while a win is worth one point to the victor and none to the loser.For the most part,...
if no capture has been made and no pawn
Pawn (chess)
The pawn is the most numerous and weakest piece in the game of chess, historically representing infantry, or more particularly armed peasants or pikemen. Each player begins the game with eight pawns, one on each square of the rank immediately in front of the other pieces...
has been moved in the last fifty consecutive moves (fifty moves by each side). The intended reason for the rule is so that a player with no chance to win cannot be obstinate and play on indefinitely , or seek a win purely due to an opponent's fatigue. All of the basic checkmate
Checkmate
Checkmate is a situation in chess in which one player's king is threatened with capture and there is no way to meet that threat. Or, simply put, the king is under direct attack and cannot avoid being captured...
s can be accomplished in well under fifty moves.
In the 20th century it was discovered that some positions of certain endgames can only be won in more than fifty moves (without a capture or a pawn move). The rule was changed to include certain exceptions in which one hundred moves were allowed with particular material combinations. However, more and more exceptions were discovered and in 1992 FIDE abolished all such exceptions and reinstated the strict fifty-move rule.
Statement of rule
The relevant part of the official FIDEFédération Internationale des Échecs
The Fédération Internationale des Échecs or World Chess Federation is an international organization that connects the various national chess federations around the world and acts as the governing body of international chess competition. It is usually referred to as FIDE , its French acronym.FIDE...
laws of chess is rule 9.3:
- The game is drawn, upon a correct claim by the player having the move, if
- (a) he writes on his scoresheet, and declares to the arbiter his intention to make a move which shall result in the last 50 moves having been made by each player without the movement of any pawn and without the capture of any piece, or
- (b) the last 50 consecutive moves have been made by each player without the movement of any pawn and without the capture of any piece.
Naturally, if a player writes down his next move as under (a) above, it must not be a pawn move or a capture for a valid claim. Additionally, a claim does not have to be made at the first opportunity – it can be made any time when there were no captures or pawn moves in the last fifty moves.
A game is not automatically declared a draw under the fifty-move rule – the draw must be claimed by a player on his turn to move. Therefore a game can continue beyond a point where a draw could be claimed under the rule. Theoretically, a game could continue indefinitely this way; but in practice, when a draw under the fifty-move rule can be claimed, one of the players is usually happy to claim it .
Games drawn under the fifty-move rule before the endgame are rare. One example is the game Filipowicz versus Smederevac, Polanica Zdrój 1966, which was drawn on move 70 without any captures having been made in the whole game and with the last pawn being moved on move 20.
Timman vs. Lutz
| Timman vs. Lutz, 1995 |
|---|
In this 1995 game between Jan Timman
Jan Timman
Jan Timman is a Dutch chess Grandmaster who was one of the world's leading players from the late 1970s to the early 1990s. At the peak of his career he was considered to be the best non-Soviet player and was known as "The Best of the West"...
and Christopher Lutz
Christopher Lutz
Christopher Lutz is a German chess grandmaster and the German chess champion in 1995 and 2001. In 2000 he was a member of the German team that won a silver medal in the 34th Chess Olympiad in Istanbul....
, an endgame with a rook and bishop versus a rook occurred. White is striving for the winning Philidor position
Philidor position
The Philidor position usually refers to an important chess endgame which illustrates a drawing technique when the defender has a king and rook versus a king, rook, and a pawn. It is also known as the third rank defense, because of the importance of the rook on the third rank cutting off the...
while Black is employing the drawing Cochrane Defense and the "second-rank defense" (see rook and bishop versus rook endgame). Black was defending well in the difficult defense and could have claimed a draw on the 119th move. Lutz notes that he claimed a draw on move 121, ironically when making a move that gets into a losing position .
Karpov vs. Kasparov
| Karpov vs. Kasparov, Tilburg, 1991 | |
|---|---|
A draw by the fifty-move rule could have been claimed after Black's 112th move in a 1991 game between Anatoly Karpov
Anatoly Karpov
Anatoly Yevgenyevich Karpov is a Russian chess grandmaster and former World Champion. He was the official world champion from 1975 to 1985 when he was defeated by Garry Kasparov. He played three matches against Kasparov for the title from 1986 to 1990, before becoming FIDE World Champion once...
and Garry Kasparov
Garry Kasparov
Garry Kimovich Kasparov is a Russian chess grandmaster, a former World Chess Champion, writer, political activist, and one of the greatest chess players of all time....
, but neither player claimed it. The last capture occurred on White's 63rd move (and the last pawn move occurred before that). By FIDE rule 9.3 part (a), White could have written his 113th move (which wouldn't have been a capture or pawn move) on his scoresheet and claimed a draw. By FIDE rule 9.3 part (b), after White's 113th move, either player could have claimed a draw on their turn to move, without having to write down their next move. Instead, the game continued a few more moves:
- 113. Ng5 Ra6+
- 114. Kf7 Rf6+
- 115. ½-½
The players agreed to a draw
Draw by agreement
In chess, a draw by agreement is the outcome of a game due to the agreement of both players to a draw. A player may offer a draw to his opponent at any stage of a game; if the opponent accepts, the game is a draw. The relevant portion of the FIDE laws of chess is article 9.1...
at this point because after 115. Kxf6 the position is a stalemate
Stalemate
Stalemate is a situation in chess where the player whose turn it is to move is not in check but has no legal moves. A stalemate ends the game in a draw. Stalemate is covered in the rules of chess....
. If 115. Ke8 Rxf5 116. Nxf5, and the position is clearly drawn because the two knights cannot force checkmate
Checkmate
Checkmate is a situation in chess in which one player's king is threatened with capture and there is no way to meet that threat. Or, simply put, the king is under direct attack and cannot avoid being captured...
(see two knights endgame).
Lputian vs. Haroutjunian
| Lputian vs. Haroutjunian, 2001 | |
|---|---|
An unusual occurrence happened in a game in the 2001 Armenian Championship
Armenian Chess Championship
This is a list of all the winners of the Armenian Chess Championship. The first championship was played in 1934, when Armenia was a part of the Transcaucasian SFSR. Championships were held sporadically in the Armenian SSR until 1945, when they became contested every year; this has continued today...
between Smbat Lputian
Smbat Lputian
Smbat Gariginovich Lputian is an Armenian chess Grandmaster. He was first at tournament in Berlin 1982, shared first at Athens 1983 and at Irkutsk 1983, first at Sarajevo 1985 and at Irkutsk 1986, shared first at Hastings 1986-87 and first at Dortmund 1988...
(who won the championship) and Gevorg Haroutjunian. The last pawn move was on White's 86th move and no captures occurred after it. (The game was a theoretical draw from before here until Black's 141st move.) Black could have claimed a draw after White's 136th move (or any of the subsequent moves). Instead, the game continued and Black resigned on his 142nd move – even though the right to claim a draw was still in effect .
History
The rule, which was introduced by Ruy López de Segura in his 1561 book, has a long history . At one time, it was believed that all winnable games could be won without exceeding the fifty-move rule. However, in the early twentieth century, some exceptions were found, including A. A. TroitskyAlexey Troitsky
Alexey Alexeyevich Troitsky, or Alexei, or Troitzky is considered to have been one of the greatest composers of chess endgame studies. He is widely regarded as the founder of the modern art of composing chess studies...
's analysis of the two knights endgame as well as the endgame of a rook and bishop versus a rook. The rules of chess were revised several times to admit exceptions to the fifty-move rule for certain specific situations. Early on, the fifty-move rule applied to tournament games but not to match games .
During the time periods when the fifty-move rule admitted exceptions, there were a number of revisions. In 1928 FIDE enacted rules that if an endgame theoretically requires more than fifty moves to force checkmate, twice that number of moves were allowed. For instance, in the rook and bishop versus rook endgame, 132 moves were allowed, since it was twice the 66 moves that were thought to be required at that time . (The actual maximal number of moves needed is 59.) . In 1952 FIDE revised the law, allowing for one hundred moves in such positions but requiring that players agree to an extension for these positions before the first move is made. This was still in effect in 1960. The positions were not specified in the rules, to allow for the possibility of more positions requiring more than fifty moves to be discovered (which is what happened). These positions were understood to require more than fifty moves:
- rook and bishop versus a rook
- two knights versus a pawn safely blocked by a knight behind Triotsky line
- rook and pawn on a2 versus a bishop on black squares and a pawn on a3, plus the equivalent positions in the other corners .
Article 12.4 of the 1965 FIDE rules states:
The number of moves can be increased for certain positions, provided that this increase in number and these positions have been clearly established before the commencement of the game.Harkness notes that "Some of these unusual positions have been established and accepted by FIDE.", including two knights versus a pawn . The 1975 and 1977 versions of the rules included the same wording (also not specifying the positions or the number of moves) , .
In 1984 the rule was modified and it became Article 10.9. Now one hundred moves were explicitly specified and the positions above were listed in the rule . (The language about the positions and number of moves having to be specified in advance of the game was dropped.) Ken Thompson
Ken Thompson
Kenneth Lane Thompson , commonly referred to as ken in hacker circles, is an American pioneer of computer science...
's investigations in the 1980s using the Belle
Belle (chess machine)
Belle was the name of a chess computer and its associated software, developed by Joe Condon and Ken Thompson at Bell Labs in the 1970s and 1980s. Belle was the first computer built for the sole purpose of chess playing. The strongest computer chess system of its time, Belle achieved a USCF rating...
chess computer discovered numerous endgames winnable in more than fifty moves. However, these often involved seemingly random moves that defied human comprehension or analysis, in situations that would hardly ever occur in real gameplay. In 1989 the rule (still Article 10.9) was changed to 75 moves, and the listed positions were:
- rook and bishop versus rook
- Two knights versus a pawn (no mention of the Troitsky line)
- A queen and a pawn on the seventh rank versus a queen (see queen and pawn versus queen endgameQueen and pawn versus queen endgameThe queen and pawn versus queen endgame is a chess endgame in which both sides have a queen and one side has a pawn, which he is trying to promote. It is very complicated and difficult to play. Cross-checks are often used as a device to win the game by forcing the exchange of queens...
) - Queen versus two knights (see pawnless chess endgame#Queen versus two minor pieces)
- Queen versus two bishops
- Two bishops versus a knight (see pawnless chess endgame#Minor pieces only) .
The rule was changed to allow for fifty moves in all positions. Some sources say that the 1989 rule was in effect only a "year or so" or a "few years" , but one source of the 1992 rules gives the pre-1984 wording: "... increased for certain positions if it was announced in advance" . By 2001 the rule was Article 9.3 and allowed fifty moves for all positions .
Research in the field of how many moves are required to win certain endgames has continued. Exhaustive retrograde analysis
Retrograde analysis
In chess, retrograde analysis is a computational method used to solve game positions for optimal play by working backward from known outcomes , such as the construction of endgame tablebases. In game theory at large, this method is called backward induction...
using faster computers to build endgame tablebase
Endgame tablebase
An endgame tablebase is a computerized database that contains precalculated exhaustive analysis of a chess endgame position. It is typically used by a computer chess engine during play, or by a human or computer that is retrospectively analysing a game that has already been played.The tablebase...
s has uncovered many more such endgames, often of previously unsuspected length. , the record is 517 moves (assuming optimal play by both sides) to make a piece capture or exchange that achieves a simpler and more obviously winnable sub-endgame, for a particular position involving a queen and knight versus a rook, bishop, and knight.
Many of the longest games on record involve the rook and bishop versus rook endgame, when the rule for more moves was in effect. (See pawnless chess endgame and rook and bishop versus rook endgame.)
See also
- Draw (chess)Draw (chess)In chess, a draw is when a game ends in a tie. It is one of the possible outcomes of a game, along with a win for White and a win for Black . Usually, in tournaments a draw is worth a half point to each player, while a win is worth one point to the victor and none to the loser.For the most part,...
- Rules of chessRules of chessThe rules of chess are rules governing the play of the game of chess. While the exact origins of chess are unclear, modern rules first took form during the Middle Ages. The rules continued to be slightly modified until the early 19th century, when they reached essentially their current form. The...
- Threefold repetitionThreefold repetitionIn chess and some other abstract strategy games, the threefold repetition rule states that a player can claim a draw if the same position occurs three times, or will occur after their next move, with the same player to move. The repeated positions need not occur in succession...
- Chess endgame#Longest forced win