157. the cannon fires over a black piece, by the cannon

Helpmates in xiangqi

4 moves

Black moves first and both sides cooperate: Black, Red, Black, Red, and Red's second move mates. Black has 1 legal first moves and exactly one of them works. 18 pieces, Black 51 to Red 8.5 in material, mate by the cannon. Themes: the cannon fires over a black piece, the general w…