Can you block a check by capturing a piece sitting on the blocking square?
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
No, because the situation never arises. Every point you could block on is empty: a chariot checks only down a clear line, and a horse checks only while its leg point is empty. Against a cannon the line holds exactly one piece, the screen, but capturing it with another piece puts that piece on the point as the new screen, so the check stands. A block always goes on an empty point.
Why this comes up
It is easy to hope for one move that blocks and captures at once. Against a single check it does not exist: the blocking points are empty by definition, so there is nothing on them to capture.
What a block needs
The piece has to reach an empty point between the checking piece and the general legally, following its own movement rules, or the leg point against a horse, and the resulting position must not leave your general in check from something else. Against a cannon, a block adds a second piece to its line, which switches the check off.
Related questions
Does this work against a horse check the same way?
It is the same: a horse checks only while its leg point is empty, so there is nothing there to capture. Put a piece on the leg point to block the check, capture the horse, or move the general.
Is this any different from a normal capture that answers check?
Yes. The usual capture takes the checking piece itself. Capturing a cannon's screen with another piece does not help, because that piece becomes the new screen; only the general taking an undefended screen next to it ends the check, since nothing is then left between it and the cannon.
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