57. model mate, 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 36 legal first moves and exactly one of them works. 17 pieces, Black 40 to Red 9 in material, mate by the cannon. Themes: pure mate, model mate, the cannon fires over a blac…