Check
A check is a direct attack on the king: an enemy piece threatens to capture it on the next move. The rule is absolute: when your king is in check, you must deal with the threat immediately, before anything else. Any move that leaves your king in check is illegal.
Check is notated with the + symbol attached to the move (for example Re8+). If no response exists, it’s no longer a simple check: it’s checkmate, and the game ends there.
The three ways to respond
Facing a check, you only have three options:
- Move the king to a square that isn’t attacked.
- Block the attack by placing one of your pieces between the king and the attacker.
- Capture the piece giving check.
In this position, Black can capture the rook with their own (Rxe8), slide the bishop to f8 to cut the attacking line, or move the king to h7. Three responses available: this check is harmless. The moment to worry is when the list is empty: zero responses means mate.
Two limits worth knowing: you can’t block a knight check (it jumps over everything), nor a check from a piece right next to the king. In both cases, only fleeing or capturing remains.
What a check forbids
As long as your king is in check, your options are limited:
- You can’t ignore the check to play something else, even a move that would win the opposing queen.
- You can’t castle to escape it: castling is forbidden while the king is in check.
- You can’t respond with a move that leaves your king in check somewhere else on the board.
On the other hand, giving check is never mandatory, and it isn’t always a good idea. A check that pushes the enemy king to a safer square costs you a tempo. Before giving any check, ask yourself what it actually gains you.
Check as a weapon
Used well, check is a powerful tactical tool, because it forces a response: you know your opponent must deal with it before anything else. That lets you gain a tempo to save a threatened piece, drag the king onto a bad square, or combine the check with a second threat: a knight fork hitting both king and queen is the best-known example.
Check can even save a lost game: a player who gives endless checks the opponent can’t escape earns a draw by repetition. That’s perpetual check, the classic lifeline of desperate positions.
Frequently asked questions
Do you have to say “check” out loud?
No. In competition, nothing is announced: each player is responsible for watching their own king. If a player misses the check and plays an illegal move, the arbiter restores the position and awards two bonus minutes to the opponent; a second illegal move loses the game. Among friends, announcing it is still a common courtesy, especially against a beginner.
What happens if no response exists?
It’s checkmate: the king is attacked, none of the three responses work, and the game is over. The difference between an ordinary check and mate comes down to one question: is there still a legal move to save the king?
Can both kings be in check at the same time?
No, that’s impossible. Since any move that leaves your own king in check is illegal, you can never give check while exposing your own king in the process. At any point in the game, at most one of the two kings is in check.