What is a zwischenzug (in-between move) 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
A forcing move played before an expected recapture or reply, so the position changes before the obvious move happens. Rather than recapturing immediately, you insert a check or a bigger threat first. The opponent has to deal with that new problem, and only then does the original exchange get completed, on better terms.
Why it is easy to miss
Sequences that look forced, a capture answered by a recapture, feel automatic to play out, and it is precisely that automatic feeling that hides the in-between move. Before recapturing on reflex, check whether a check or a bigger threat is available first.
Where it is most common
Discovered checks are the classic vehicle, since a check must be answered before anything else happens on the board, including the recapture the opponent was expecting. A cannon threat created incidentally by another move can serve the same purpose.
Related questions
Does the in-between move have to be a check?
No, any threat urgent enough that the opponent cannot ignore it works, though checks are the most reliable.
Is this the same idea as tempo?
Related. See what a tempo actually is: a well-timed in-between move is one of the clearest ways to gain one mid-sequence.
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