Fifty-move rule

History

The rule has a long history. A precursor to chess, shatranj, had a seventy-move rule. The fifty-move rule was introduced into chess by Ruy López in his 1561 book. Pietro Carrera thought twenty-four moves was the right number, but Bourdonnais argued for sixty.

By 1800, a claim under the rule could be made only in certain specified endgames, varying between rule sets; the move-count started when the request was made rather than from the last capture or pawn move, and a capture or pawn move did not reset the count. The 1883 London tournament rules reset the count on a capture or pawn move but still started the count when the claim was made. At one time all winnable endgames were believed winnable within fifty moves, but early 20th-century exceptions were found, including Troitsky's analysis of the two knights endgame and the rook and bishop versus rook endgame.

In 1928 FIDE enacted rules allowing twice the number of moves theoretically required; for rook and bishop versus rook, 132 moves were allowed. In 1952 FIDE revised the law to allow 100 moves in such positions, requiring players to agree to an extension before the first move. The positions were not specified in the rules to allow for newly discovered positions. In 1992, FIDE abolished all exceptions and reinstated the strict fifty-move rule over the board.

Statement of rule

Under FIDE laws, a claim does not have to be made at the first opportunity; it can be made any time when there have been no captures or pawn moves in the last fifty moves. The game is not automatically declared a draw; the draw must be claimed by the player whose turn it is to move, so a game can continue beyond the point where a draw could be claimed. When a draw under the rule can be claimed, one of the players is usually happy to claim it. Games drawn under the rule before the endgame are rare; one example was Filipowicz versus Smederevac, Polanica Zdrój 1966, where no captures had been made in the whole game and the last pawn was moved on move 20.

In correspondence chess under ICCF rules, the fifty-move rule only applies when more than seven pieces remain; with seven or fewer pieces, a win or draw may be claimed using endgame tablebases. Some older tablebases do not consider the 50- or 75-move rules, so a position that is a theoretical win may be a draw in over-the-board chess, termed a 'cursed win' or 'blessed loss'. In retrograde analysis problems, castling also resets the fifty-move counter. If seventy-five moves are made without a pawn move or capture, the game is drawn unless the seventy-fifth move delivers checkmate; no claim is needed as the arbiter applies it mandatorily.

Examples

In a 1995 game between Jan Timman and Christopher Lutz, a rook and bishop versus rook endgame occurred. White aimed for the winning Philidor position while Black used the Cochrane Defense and second-rank defense. Black defended well and could have claimed a draw on the 119th move; Lutz noted he claimed a draw on move 121, ironically making a move that entered a losing position.

In a 1991 game between Anatoly Karpov and Garry Kasparov, a draw by the fifty-move rule could have been claimed after Black's 112th move, but neither player claimed it. The last capture was on White's 63rd move. The game continued: 113. Ng5 Ra6+, 114.

Kf7 Rf6+, ½-½, with the players agreeing to a draw because after 115.Kxf6 the position is stalemate. In the 2001 Armenian Championship, Smbat Lputian faced Gevorg Haroutjunian. The last pawn move was on White's 86th move with no captures after it. Black could have claimed a draw after White's 136th move but did not; Black resigned on his 142nd move after White achieved a forced winning position.

In the 2008 Aeroflot Open, Nguyễn Ngọc Trường Sơn played Maxime Vachier-Lagrave. The last capture on White's 71st move created a rook and bishop versus rook endgame. The game was a theoretical draw until Black blundered on his 113th move; White found a win but could not secure checkmate or win the black rook before the fifty-move rule took effect, and Black claimed a draw.