The fifty-move rule lets a player claim a draw if fifty consecutive moves by each side pass with no pawn move and no capture. Its purpose is to stop a game dragging on forever when neither side is making real progress. A pawn move or any capture resets the counter to zero, because those actions change the position permanently and cannot be repeated. The rule matters most in endgames where one side has a small edge but cannot force checkmate. If you are defending a difficult endgame, counting toward fifty moves can be your path to a draw.