What counts as a screen for a cannon?
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
Any single piece, of either colour and any type. Your own soldier, your opponent's chariot, an advisor — all work identically. What matters is the count, not the ownership: exactly one piece between the cannon and its target, and the target is the first piece beyond it, which must be an enemy.
The count is the whole rule
- Zero pieces in between — the cannon can move along the line but cannot capture anything on it.
- Exactly one — it can capture the first piece beyond the screen, if that piece is an enemy.
- Two or more — no capture at all.
The screen itself can never be captured by that cannon; it captures past it.
Why using enemy pieces matters
Because the defender supplies screens whether they mean to or not. A defender who leaves their elephants at home is handing the attacking cannon exactly what it needs, and the standard defensive idea — advance or trade the pieces a cannon could jump — falls straight out of that.
Related questions
Can my own general be a screen?
Yes. Any piece works, including either general.
Can a cannon capture the screen?
No. A cannon never captures without a screen, and the screen is the first piece on the line, with nothing between them to jump. The cannon can only capture past it.
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