Same position

Two moments in a game count as the same position only when more than the board picture matches. The same player must have the move, pieces of the same kind and color must occupy the same squares, and all possible moves for both sides must be the same.

The side to move is essential. An identical arrangement with White to move and Black to move represents two different positions because the available actions and the immediate meaning of checks and threats differ.

Rights that are not obvious from the pieces also matter. If an en passant capture, the special pawn capture available immediately after an opposing pawn advances two squares, was previously possible but is no longer possible, the positions are not the same. They also differ if a king or rook moved and lost castling rights, the right to make the special king-and-rook move, even after returning to the original squares.

This definition governs repetition. A third occurrence may lead to a draw after a correct claim, a formal request to the arbiter, by the player having the move; a fifth occurrence makes the game drawn automatically. The written move number and the players' remaining clock times are not part of this rules-based comparison.