Threefold repetition
A player may claim a draw if the same position is about to appear, or has appeared, three times. The same position means the same pieces on the same squares, the same side to move, the same castling rights, and the same en passant right.
The moves in between do not have to be repeated in order. Only the position has to match, three times.
Castling rights are part of the position. If the king could castle the first time and cannot castle later, it is not the same position, even if the pieces sit on the same squares.
The line below repeats a rook check until the position has occurred three times and a draw can be claimed. Step through it and watch the claim become available at the end.
On the board
8
7
6
5
4
3
2
a1
b
c
d
e
f
g
h
Starting position.
Common mistakes
- Counting three repeated moves when a pawn has moved. A pawn move makes a new position.
- Ignoring castling rights when deciding that two positions match.
- Thinking repetition is automatic in every rule set without a claim. It is a claim the player may make.