What is the flying general rule?
These answers restate the rules implemented by our open-source engine, which follows the WXF laws and is regression-tested against the official 110-diagram repetition casebook. Where an answer refers to a specific position, that position lives on the linked reference page, where the build verifies it against the engine before publishing.
Direct answer
The two generals may never face each other on the same file with nothing in between. Any move that would create the position is illegal — including moving the last piece out from between them. It is called 白臉將, and it has no equivalent in western chess.
A restriction, not a capture
Some explanations describe the general "flying" down the file to capture the other. In the WXF laws it is simply a position that may never occur, created by nobody. The practical effect is identical — the file is unusable — but it matters when you are deciding whether a specific move is legal.
What it is worth
Two things. Defensively, it means the enemy general can never step onto the file yours occupies, so your general is a free extra attacker in every bare endgame. Offensively, it creates the strongest pin in the game: a piece alone between the generals cannot move at all.
Related questions
Can I move a piece out from between the generals?
Only if another piece stays on the line or your general leaves it. Otherwise the move is illegal.
Does it apply if pieces are in the way?
No. With any piece between them the generals may share a file freely.
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