83. pure 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 33 legal first moves and exactly one of them works. 19 pieces, Black 51 to Red 8.5 in material, mate by the cannon. Themes: pure mate, the cannon fires over a black piece, a…