Does an open file help a cannon the way it helps a chariot?
These answers restate the rules implemented by our open-source engine, which follows 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. Where an answer refers to a specific position, that position lives on the linked reference page, where the build verifies it before publishing.
Direct answer
Not in the same way, and sometimes not at all. A chariot's power grows directly with how clear its lines are. A cannon needs a screen to threaten anything, so a fully open file can actually leave a cannon with nothing to capture or check, while a file with exactly one well-chosen piece on it is often far more dangerous.
Where the intuition from chess misleads
Chess-trained instincts say open lines are always good for a long-range piece. For a cannon that is only half true: an open file is good for repositioning quickly along it, but the cannon's actual threats come from lines with a single screen, which an open file by definition does not have.
What a cannon actually wants
A file or rank with exactly one piece between the cannon and a valuable target, ideally a piece the opponent cannot easily remove without cost. That is a completely different shape from the wide-open lines a chariot is hunting for, even though both pieces move similarly along clear ground.
Related questions
So is an open file ever useful to a cannon?
Yes, for mobility and repositioning to a better file, just not directly for attacking down it.
Can a cannon and chariot want different things on the same file?
Yes, and reconciling that is a real part of coordinating them together.
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