How is the flying general rule used as an endgame weapon?
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
In sparse endgames, your general effectively controls the entire file it stands on, because the enemy general can never legally stand facing it with a clear line between. Removing the last piece between the two generals, when it's your move to do so, can itself be the checking or mating move, no additional attacking piece required.
A free attacker in bare positions
Once most material is off the board, the general is often the only piece with real reach left, since it commands its whole file against the enemy general specifically. Several standard mates finish with a capture or a piece moving off the central file that exposes this check as the final blow.
The defensive side of the same coin
A defending general has to watch its own file just as carefully: keeping at least one piece between the two generals, or keeping your own general off the enemy's file entirely, is often the only thing preventing an otherwise safe-looking position from ending instantly.
Related questions
Does this count as a normal check like any other?
Yes, functionally; the position simply cannot be reached with nothing between the generals, so exposing it ends the game the same as any other check or mate.
Can this happen by accident?
Yes, which is why clearing pieces off the central file in a simplified position needs real care from both sides.
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