Check symbol

The + sign is placed at the end of a move when that move leaves the opposing king under attack. This condition is called check, and the threatened player must answer with a legal move that removes the attack.

For example, Qe3+ means that the queen moves to e3 and gives check. The + describes an objective fact about the position; it does not praise the move as an exclamation mark would.

Standard Algebraic Notation (SAN) is the system of piece letters and square names used by Portable Game Notation (PGN), a plain-text format for storing games. In SAN, + is part of the move. On an International Chess Federation (FIDE) scoresheet, the tournament form used to record moves, the sign is optional. Even when two pieces give check at once, SAN keeps a single +; the meaning of ++ depends on the convention.

If the king has no legal response, the move is checkmate and takes # instead of +.