Threefold repetition
In chess, the threefold repetition rule states that a player may claim a draw if the same position occurs three times during the game. The rule is also known as repetition of position and, in the USCF rules, as triple occurrence of position. Two positions are by definition "the same" if pieces of the same type and color occupy the same squares, the same player has the move, the remaining castling rights are the same and the possibility to capture en passant is the same. The repeated positions need not occur in succession.
The game is not automatically drawn if a position occurs for the third time – one of the players, on their turn, must claim the draw with the arbiter. The claim must be made either before making the move which will produce the third repetition, or after the opponent has made a move producing a third repetition. By contrast, the fivefold repetition rule requires the arbiter to intervene and declare the game drawn if the same position occurs five times, needing no claim by the players.
Similar rules exist in other abstract strategy games such as xiangqi and shogi whereas in Go, repetition of the immediately previous board position is completely disallowed in the first place, and in some regional rule sets repetition of any previous board position is disallowed.
Internet chess servers differ in their handling of draw by repetition. For example, Chess.com draws the game automatically upon a position's third occurrence.
Statement of the rule
The relevant rules in the FIDE laws of chess are summarized as:Although a threefold repetition usually occurs after consecutive moves, there is no requirement that the moves be consecutive for a claim to be valid. The rule applies to positions, not moves.
Perpetual check is no longer specifically mentioned in the rules of chess; such a situation will eventually resolve to a draw either by repetition, fifty-move rule or by agreement.
If the claim for a draw is incorrect, the opponent is awarded an extra two minutes, the written move must be played and the game continues. Unreasonable claims may be penalized under rule 11.5, which forbids distracting or annoying the opponent. Even if the claim is incorrect, any draw claim is also a draw offer that the opponent may accept.
Fivefold repetition
In 2014 FIDE introduced a rule providing for a mandatory draw in the event of a fivefold repetition. If the same position occurs five times, then the game is immediately terminated as a draw. If an arbiter detects a fivefold repetition, they are required to intervene and declare the game a draw. If an arbiter does not detect a fivefold repetition or fails to intervene, a player may still make a claim for fivefold repetition. If the claim is verified, the game is declared a draw regardless of any subsequent moves or result, which are void.Examples
1972 World Championship
The seventeenth and eighteenth game of the 1972 World Championship match in Reykjavik between Bobby Fischer and Boris Spassky were declared draws because of threefold repetition. The twentieth game was drawn after an incorrect claim.Fischer vs. Petrosian, 1971
In the third game of the 1971 Candidates Final Match in Buenos Aires between Bobby Fischer and Tigran Petrosian, Petrosian accidentally allowed the position after 30.Qe2 to be repeated three times. Play continued:31...Qxf4 32.Qxf7+ also leads to threefold repetition.
and then Fischer wrote his next move
on his, which is the third appearance of the position with Black to move, and he claimed a draw. At first Petrosian was not aware of what was going on. Incidentally, this was the first time a draw by threefold repetition had been claimed in his career. This also illustrates that the intermediate moves do not need to be the same – just the positions.
Capablanca vs. Lasker, 1921
As noted above, one of the players must claim a draw by threefold repetition for the rule to be applied, otherwise the game continues. In the fifth game of the 1921 World Chess Championship match in Havana between José Raúl Capablanca and Emanuel Lasker, the same position occurred three times, but no draw was claimed. After 34...h5, the moves were:Capablanca had repeated the moves to gain time on the clock. The game continued without a draw being claimed; Lasker blundered and resigned on move 46.
Two games between Alekhine and Lasker, 1914
The game between Alexander Alekhine and world champion Emanuel Lasker in Moscow 1914 ended in a short draw. After 16.Qg6 the players agreed to a draw because Alekhine can force the threefold repetition, for example 16...Qe8 17.Qxh6+ Kg8 18.Qg5+ Kh8 19.Qh6+.In the first game between the two players in the St. Petersburg tournament 1914, Alekhine, this time with the black pieces, after 21.Qd4, forced a draw by threefold repetition using a similar process.
Portisch vs. Korchnoi, 1970
A famous draw for threefold repetition occurred in the fourth game between Lajos Portisch and Viktor Korchnoi in Belgrade in the Russia vs. Rest of the World 1970 match. After 21...Qb5, in a clearly better position, Portisch allowed this position to repeat three times and was criticized by teammate Bobby Fischer for allowing it. If Portisch had won the game, the match would have been a tie. Play continued:allowing Black to claim the threefold repetition with 25...Qb5.
Kasparov vs. Deep Blue, 1997
In the game between Garry Kasparov and Deep Blue in New York 1997, the game ended with a draw by agreement, because after 49...Kb4, if White plays 50.g8=Q, Black can force perpetual check and claim a draw after 54.Kb1 by threefold repetition:Khamparia vs. Bo, 2018
To detect fivefold repetitions can be challenging for the arbiter. In the game Akshat Khamparia vs. Li Bo, Budapest 2018, Li twice requested a draw, saying simply "repetition". Both times the request was rejected because it was not made correctly according to the threefold repetition rule. Li was later checkmated. Li disputed the result, indicating that the position had occurred five times. The arbiter was able to verify fivefold repetition at moves 60, 62, 68, 73 and 75. Had the fivefold repetition rule not been in effect, the result would have stood, as no correct claim for threefold repetition had been made. Under the fivefold repetition rule, however, the fifth occurrence of a position immediately terminates the game, and subsequent moves become irrelevant. The result was therefore overturned, and the game was declared a draw.Opening line
An Austrian Attack line from the Pirc Defence has been analyzed out to a draw by threefold repetition. After the moves 1.e4 d6 2.d4 Nf6 3.Nc3 g6 4.f4 Bg7 5.Nf3 c5 6.Bb5+ Bd7 7.e5 Ng4 8.e6 fxe6 9.Ng5 Bxb5! 10.Nxe6 Bxd4! 11.Nxd8 Black can force perpetual check and so the draw by the following moves:15...Bf2+ is only a twofold repetition, as White lost their castling right only after 12.Kd2. Threefold repetition will be in effect on the next occurrence of the position.
Grandmaster draws
A grandmaster draw is characterised as a short draw between high-level players, typically intended to hold position without the expenditure of mental energy. As short draws by agreement are sometimes frowned upon or outright banned in tournaments, some players circumvent such rules by playing out lines known to end in threefold repetition draws. The Berlin draw in the Ruy Lopez is one of the more commonly used lines, while Magnus Carlsen and Hikaru Nakamura finished out a dead rubber at the Magnus Carlsen Invitational with a variation of the Bongcloud Attack – Nakamura admitted that with both players secure in passage to the next round of the tournament he saw no value in attempting to force the win.Repeating a position to gain time
Players sometimes repeat a position once not in order to draw, but to gain time on the clock or to bring themselves closer to the time control. Occasionally, players miscount and inadvertently repeat the position more than once, thus allowing their opponent to claim a draw in an unfavourable position. The game between Ponomariov and Adams in Wijk aan Zee 2005 may have been an example of this.Incorrect claims
Even top players have made [|incorrect claims] of a draw under this rule. The Karpov–Miles game is an example of the right to castle having to be the same in all positions. The Fischer–Spassky game is an example that it must be the same player's move in all three positions.Karpov vs. Miles, 1986
The clause about the right to castle is a subtle but important one. In a game between grandmasters Anatoly Karpov and Tony Miles in Tilburg 1986, Karpov had less than five minutes remaining on his clock in which to finish a specified number of moves or forfeit the game. He claimed a draw by repetition after checking his scoresheet carefully, whereupon it was pointed out to him that in the first occurrence of position, Black's king had had the right to castle, whereas in the second and third it had not. Tournament rules stipulated that a player be penalized with three minutes of their time for incorrect claims, which left Karpov's flag on the verge of falling. By then, Miles had taken the draw. After 22.Nb5, play continued:Black was able to castle the first time the arrangement of pieces in the diagram occurred, but not when the arrangement was repeated.