Double check is where a King is in check from two enemy pieces. Double check is uncommon, but can occur legally in a game of chess, and forces the King to move. But triple check is not possible (legally).
Double check occurs legally via a “discovered check”. The moving piece must uncover a discovered check, while also moving to check the enemy King itself. Discovered check can occur from a Rook or a Knight uncovering a diagonal check (from a Bishop or Queen), or by a Bishop or Knight uncovering a horizontal or vertical check (from a Rook or Queen). A Queen move cannot legally cause double check, as it cannot cause discovered check from behind it (the King is already in check from the Queen!). A pawn move also cannot cause double check.
Double check also occurs illegally in beginner games. The King is often left in check for many moves, or moves to a square controlled by multiple pieces.
Double check is not a win. The only reply to a double check is for the King to move. A double check cannot be blocked, nor can both checking pieces be captured. A King also cannot “castle out of check”. If the King cannot find a safe square to move to away from a double check, then it’s checkmate.
Related Chess Rules Topics
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