Smothered mate

In chess, a smothered mate (or informally, smother mate) is a checkmate delivered by a knight in which the mated king is unable to move because it is completely surrounded (or smothered) by its own pieces, which a knight can jump over. The mate is usually seen in a corner of the board, since only three pieces are needed to surround the king there, less than anywhere else. The most common form of smothered mate is seen in the adjacent diagram. The knight on f7 delivers mate to the king on h8, which is prevented from escaping the check by the rook on g8 and the pawns on g7 and h7. Similarly, White can be mated with the white king on h1 and the knight on f2. Analogous mates on a1 and a8 are rarer because kingside castling is more common than queenside castling and brings the king closer to the corner.