63. pure mate, by the horse

Helpmates in xiangqi

4 moves

Black moves first and both sides cooperate: Black, Red, Black, Red, and Red's second move mates. Black has 20 legal first moves and exactly one of them works. 17 pieces, Black 37.5 to Red 8 in material, mate by the horse. Themes: pure mate, Black blocks its own general, Red captu…