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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 moves (for this purpose a "move" consists of a player completing his turn followed by his opponent completing his turn). The purpose of this rule is to prevent a player with no chance of winning from obstinately continuing to play indefinitely , or seeking to win purely by tiring the opponent out. All of the basic checkmates can be accomplished in well under 50 moves. However in the 20th century it was discovered that certain endgame positions are winnable but require more than 50 moves (without a capture or a pawn move). The rule was therefore changed to allow certain exceptions in which 100 moves were allowed with particular material combinations. However, more and more such winnable positions were later discovered, and in 1992 FIDE abolished all such exceptions and reinstated the strict 50-move rule. == Statement of rule == The relevant part of the official FIDE laws of chess is rule 9.3:〔(FIDE Laws of Chess ), July 2014〕 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. 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 . In 2014 FIDE amended the rules to eliminate the possibility that a game could continue without end. Rule 9.6b states that if 75 consecutive moves have been made without movement of any pawn or any capture, the game is drawn unless the last move was checkmate.〔 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 having been moved on move 20. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Fifty-move rule」の詳細全文を読む スポンサード リンク
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