What is threefold repetition?

Threefold repetition is a rule in chess that applies when the same position of the pieces occurs three times during a game. If the exact same position occurs three times, with the same player to move, then the game is declared a draw. This rule is intended to prevent players from repeating the same moves over and over again, in an attempt to force a win or a draw. The rule can only be claimed by a player on their turn, and they must mention it to the arbiter or their opponent before making their move. The position does not have to occur in consecutive moves; it can occur at any point during the game, as long as the position is exactly the same on all three occasions. Threefold repetition is one of the methods by which a chess game can end in a draw, along with stalemate, insufficient material, and the fifty-move rule.