Sam Loyd stalemated Black on the tenth move in chess
Chess has a famous answer. In Sam Loyd’s ten-move game, Black still has ten pieces, the queen and both rooks among them, and none of them can move. Oz Problems has the history.
Fog of war is harder. There you see only the squares your pieces reach, and a king may step into check, so a side is stuck only when nothing can move at all. In Sven’s 2011 TalkChess game, Black ran out of moves after 63 plies; we found a route to the same final position in 35. Both are in this study.
Nanao Okumura stalemated Red with all sixteen pieces on the board
Nanao Okumura posted an earlier xiangqi stalemate on Zhihu in 2019, built for a different record: after 136 plies Red still has all sixteen pieces, and none of them can move. Black lost nine and took nothing. Chinese-language sites mostly blocked our search, so shorter published games may exist. We found a route to his final position in 116 plies, the fewest possible; it is the last chapter of the study.
Black is stalemated after 21 plies, held mostly by its own pieces
Two red cannons hold the pieces that could move. The one on e7 looks at the general through Black’s chariot and cannon, and the one on b10 through an elephant and an advisor. The chariot, the cannon and that elephant each have a move, and each of those moves leaves the general in check. Everything else is boxed in by its own pieces or by the red chariot on h9. Red took eight pieces on the way, Black one.
A computer search found it by keeping the most cramped positions
Both sides play toward one goal, stalemating Black, as in a helpmate. Every line is far too many to search past a few moves, so after each move the search keeps a fixed number of positions, the ones where Black has the fewest legal moves, and drops the rest. Each black piece that can still move counts heavily against a position. The search stops at the first position where Black is to move, has no legal move and is not in check.
Dropping positions is what makes it fast, and it is also why it can miss a shorter line. Run the other way, it stalemated Red in 22 plies, which is in the study with the others.
No stalemate is possible in under 9 plies
A search of every line proves that no game stalemates Black within 7 plies, and none stalemates Red within 8. So a stalemate shorter than ours, if one exists, takes 9 to 20 plies. Find one, or prove there is none, and post it in the forum.