Can a cannon cause a perpetual chase in xiangqi?
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
Yes. A cannon repeatedly threatening the same undefended enemy piece, whether by moving the cannon itself or by adding and removing its own screen to switch the threat on and off, is a textbook way a perpetual chase can arise, and the side doing the chasing is the one required to vary under the repetition rules.
The screen trick that causes it
Because a cannon's threat can be turned on or off just by adding or removing a screen, a player can create the appearance of a fresh threat each move without actually changing what is under attack. Repetition rules look past the mechanism and at the outcome: the same piece is being chased, over and over, and that must stop.
How it is normally resolved
The chasing side has to either capture the piece, abandon the chase for a genuinely different plan, or accept a draw if repetition results. See perpetual check and chase for how arbiters and engines judge exactly what counts as chasing.
Related questions
Does chasing a defended piece with a cannon count the same way?
No, chasing a piece that is adequately defended generally does not count as an illegal perpetual chase.
Is this specific to cannons?
No, any piece can cause a perpetual chase; the cannon's on-off screen trick just makes it a particularly common source of borderline cases.
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