Cannon at the bottom of the sea
海底捞月 is the classic chariot-and-cannon endgame kill: the general anchors the centre file, and the cannon sinks to the very bottom of the board on the king's own file — here d0. It fires through Black's guard rook on d7: that rook can never capture the mating chariot (it would merely become the new screen), and the king may never step to e9 because Red's general glares up the open centre. Scoop the moon: crash the chariot onto the last barrier — taking it is illegal, and there is nowhere left to run.