Check

A king is in check when it is under attack by at least one enemy piece. A piece unable to move because it would place its own king in check (it is pinned against its own king) may still deliver check to the opposing player.

It is illegal to make a move that places or leaves one's king in check. The possible ways to get out of check are:

• Move the king to a square where it is not in check.
• Capture the checking piece (possibly with the king).
• Block the check by placing a piece between the king and the opponent's threatening piece.

If it is not possible to get out of check, the king is checkmated and the game is over (see the next section).

In informal games, it is customary to announce "check" when making a move that puts the opponent's king in check. However, in formal competitions, check is rarely announced.