133. pure mate, by the soldier

Helpmates in xiangqi

4 moves

Black moves first and both sides cooperate: Black, Red, Black, Red, and Red's second move mates. Black has 29 legal first moves and exactly one of them works. 21 pieces, Black 45 to Red 14 in material, mate by the soldier. Themes: pure mate, a piece already in the way, the genera…