The epaulette mate is a checkmate pattern in which the enemy king is mated on a rank or file while two of its own pieces block both lateral escape squares — resembling the epaulettes on a military uniform flanking it on either side.
This mate typically occurs in the middlegame or endgame when a queen delivers check directly along the king’s rank or file, and the king cannot escape left or right because two of its own pieces (often rooks or pawns) occupy those squares. For example, if the white king sits on e8 with its own rooks on d8 and f8, a black queen on e1 gives check along the e-file: the king is mated — its own rooks deny it the only lateral escape squares.
In practice, look for positions where the opposing king is stuck on the back rank with friendly pieces on adjacent squares. That configuration is your signal: a sacrifice or a queen maneuver toward the king’s file may be enough to trigger the pattern. Always check whether the pieces flanking the enemy king can move or be captured — if they cannot, the epaulette mate may be within reach.