The longest forced mates in xiangqi

For each material class, the position that takes longest to mate and the line that does it, both sides playing best. The numbers come from endgame tablebases, which hold every legal position of a class with its exact distance to mate, so a "longest mate" here is a fact about the class rather than the deepest thing a search happened to find. Five of these seven lines end with the loser having no legal move rather than in checkmate, which is a way to lose that chess does not have.

7 chapters

1. A horse and a soldier against the full guard: mate in 65129 moves

   a horse and a soldier against a general with two advisors and two elephants: the deepest position in the class, and the longest forced win it contains, 65 moves. Both sides play best: the winner mates as fast as the position allows, the loser holds out as long as it can. The lose…

2. Two cannons against the full guard: mate in 52104 moves

   two cannons against a general with two advisors and two elephants: the deepest position in the class, and the longest forced win it contains, 52 moves. Both sides play best: the winner mates as fast as the position allows, the loser holds out as long as it can. The loser is left…

3. Chariot and full guard against full guard: mate in 4386 moves

   a chariot, with its own advisors and elephants, against the same: the deepest position in the class, and the longest forced win it contains, 43 moves. Both sides play best: the winner mates as fast as the position allows, the loser holds out as long as it can. Checkmate. From an…

4. A cannon and a horse against the full guard: mate in 3671 moves

   a cannon and a horse against a general with two advisors and two elephants: the deepest position in the class, and the longest forced win it contains, 36 moves. Both sides play best: the winner mates as fast as the position allows, the loser holds out as long as it can. The loser…

5. A chariot against the full guard: mate in 3264 moves

   a chariot against a general with two advisors and two elephants: the deepest position in the class, and the longest forced win it contains, 32 moves. Both sides play best: the winner mates as fast as the position allows, the loser holds out as long as it can. Checkmate. From an e…

6. Two horses against the full guard: mate in 3162 moves

   two horses against a general with two advisors and two elephants: the deepest position in the class, and the longest forced win it contains, 31 moves. Both sides play best: the winner mates as fast as the position allows, the loser holds out as long as it can. The loser is left w…

7. Two soldiers against the full guard: mate in 2243 moves

   two soldiers against a general with two advisors and two elephants: the deepest position in the class, and the longest forced win it contains, 22 moves. Both sides play best: the winner mates as fast as the position allows, the loser holds out as long as it can. The loser is left…