Smothered palace (闷宫)
Every position, move and legality claim on this page is verified programmatically against our open rules engine, which implements the WXF laws for movement, checkmate and both repetition rulings: a side that forces a repetition by perpetual check or perpetual chase loses rather than drawing. The chase half has not been validated against the official casebook.
Direct answer
闷宫 is a mate in which one cannon finishes a general whose own pieces have taken away its escape points. The cannon fires through a screen to give check; the general cannot step aside because its own advisors occupy the palace points beside it, and it cannot leave the palace at all. It is the most famous cannon mate in xiangqi, and it has no equivalent in western chess because no chess piece attacks through another.
The position
Red to play, and there is exactly one move that mates. The cannon is on the left edge; the red soldier on the d-file is about to become the thing it fires through.
Red to play and mate in one.
Xiangqi position. Red: soldier d3, cannon a1, general d0. Black: advisor d8, general d7, advisor e7. Red to move.
Why the general has nothing
Worth walking through, because this is the whole pattern and it is quicker to understand than to memorise. The general stands on d7 with its own advisors on d8 and e7.
- It cannot step sideways or back. d8 and e7 are the only palace points next to it, and its own advisors are on both. Nothing of Red's is doing that work — Black did it.
- It cannot run forward. The point in front is outside the palace, and a general may never leave.
- It cannot capture the cannon. The cannon is six points away down the file.
- It cannot block, and this is the xiangqi-specific part. Interposing between the cannon and its target would give the cannon a second screen, which would end the check rather than survive it — but Black has only advisors, and they cannot reach any point on that stretch of the file anyway.
- The advisors cannot move either. Not because they are pinned, but because no advisor move answers the check, and a move that leaves your general in check is illegal.
The engine confirms the count: after the mating move, Black has zero legal moves.
Being on the wrong end of it
The uncomfortable lesson in 闷宫 is that the advisors are complicit. A defender who keeps both advisors at home, which feels safe, builds the cage. Three habits help:
- Watch for a cannon on your general's file or rank with exactly one piece between. That is not a quiet position; that is a mate one tempo away.
- Keep a flight point genuinely empty. An advisor sitting beside the general is not defending it against a cannon — nothing blocks a cannon by standing next to the target — and it is removing a square.
- Count your general's legal moves, not its attackers. A general with one legal move is one forcing check from being mated, whatever the material says.
The broader family, where the mating piece is a soldier or a chariot rather than a cannon, is 闷杀.
Related questions
What is 闷宫 in xiangqi?
A mate where a single cannon finishes a general whose own pieces occupy its escape points. The cannon checks through a screen; the general cannot step aside because its own advisors are in the way, and it cannot leave the palace.
Why can the general not block a cannon check?
Because a cannon needs exactly one piece between it and its target. Interposing a second one does not block the check — it removes it, which is a legal way out when it is available. In 闷宫 it is not available, because the defender has nothing that can reach the file.
Is there a smothered mate in chess?
There is a smothered mate, delivered by a knight to a king boxed in by its own pieces, but not this one. 闷宫 depends on a piece that attacks through another, and chess has none.
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