What is a counter-sacrifice in xiangqi?
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
A counter-sacrifice is giving up material immediately in response to an attack, rather than defending passively, in order to seize the initiative back or force the position onto your own terms. It is a defensive resource that behaves like an attacking one: instead of absorbing the threat, you answer it with a threat of your own.
Why giving material back can be the best defence
A purely passive defence sometimes leaves every one of your pieces tied down answering the opponent's plan, with no moves left to generate anything yourself. Sacrificing back, offering a piece that creates a check, a fork, or a bigger threat than the one you are facing, can force the opponent to react to you instead, which is often worth more than the material given up.
When it works and when it is just losing material
A sound counter-sacrifice needs its own concrete follow-up, exactly like any other sacrifice; see finding a sacrifice that actually works for the general test. The difference here is timing: it is played specifically while under attack, as an alternative to defending passively, not as a calm, unforced idea from a quiet position.
Related questions
Is this the same as a desperado?
Different: a desperado piece is already lost and grabs something on the way out; a counter-sacrifice is a deliberate choice made while other options are still available.
Does this only work when you are already worse?
It is most common there, but it can also apply mid-attack against an equal position where passive defence would hand over the initiative for nothing.
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