How does threefold repetition work in chess?
If the same position occurs three times, with the same side to move and the same moves available, the game is drawn. Trindo detects it automatically.
Threefold repetition ends a game in a draw when the same position appears on the board three times. The occurrences don’t have to be back to back; they can be spread across the game.
What counts as the same position
- Every piece is on the same square.
- The same player is to move.
- The same moves are available, including castling rights and en passant captures.
Example
Both sides shuffle a knight out and back: 1. Nf3 Nf6 2. Ng1 Ng8 returns to the starting position for the second time. Two more knight trips (3. Nc3 Nc6 4. Nb1 Nb8) reach it a third time, and the game is drawn on that last move.
In Trindo
You don’t need to claim the draw. As soon as the third occurrence is on the board, the game ends and the result reads “Threefold repetition”. It is one of several automatic draws, alongside the fifty-move rule, stalemate and insufficient material.
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