Fifty move rule

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. The relevant part of the official 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 doesn't 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.
See more at Wikipedia.org...