noun
losing move; game-losing move
Used in go and shogi for a move that directly causes defeat. Often contrasted with 勝着 (winning move).
See also: 勝着
終盤で痛恨の敗着を打ってしまった。
I made a painful losing move in the endgame.
あの一手が敗着だったと後で気づいた。
I later realized that move was the one that cost me the game.