What is check in chess?
B · Beginner · Winning and drawing · 6 of 10A king is in check when an opponent's piece attacks it. The player must deal with it on that move. There are three ways: move the king to a safe square, capture the attacking piece or put a piece in the way. A player may never make a move that leaves their own king in check.
How it works
- In check: the king "is attacked by one or more of the opponent's pieces".
- Must be answered: no move is legal that leaves the king in check.
- No walking into check: no move is legal that exposes the player's own king to check.
- A pinned piece still gives check: a piece attacks a square even if moving there would expose its own king.
- Kings keep apart: two kings can never stand on adjoining squares, because each would be attacking the other.
- Saying "check": the Laws do not require it.
- A move that leaves the king in check: is an illegal move, to be taken back.
The glossary has the check, the king, the checkmate, the illegal move, the pin and the capture.
Tricky cases
Does a player have to say "check"?
No. Nothing in the Laws requires it. It is a habit from casual play.
A player in check does not notice and plays another move. Do they lose?
No, not for the first one. It is an illegal move: the position is put back, the opponent gets two extra minutes and the player must make a legal move. A second illegal move by the same player loses the game.
A piece that cannot move without exposing its own king is aimed at my king. Am I in check?
Yes. A piece attacks a square "even if this piece is constrained from moving to that square".
Can a king give check to the other king?
No. To do so it would have to stand next to the other king, and it would then be in check itself.
Why the rule exists
The king cannot be captured, so the game needs a rule for the moment it is threatened. Check is that rule. It makes the threat to the king override everything else on the board, which is why a check can be used to win time or force a piece to move.
Where it differs
| Where | What changes | Source |
|---|---|---|
| King attacked | Check: must be answered at once | FIDE Laws 3.9 |
| King attacked with no legal move | Checkmate | FIDE Laws 1.4 |
| No legal move and not in check | Stalemate, a draw | FIDE Laws 5.2.1 |
| Illegal move noticed in rapid or blitz without full supervision | It stands unless claimed or seen before the opponent's next move | FIDE Laws A.5.2 |
From the rule book
FIDE, Laws of Chess (approved 7 August 2022, applied from 1 January 2023), Articles 1.4, 3.1.3, 3.9, 3.10 and 7.5 and Appendix A.5.2. Checked 14 October 2026. Official document: FIDE Laws of Chess taking effect from 1 January 2023 (FIDE Handbook E.01).