Is chasing a piece always illegal to repeat 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
No. Only a repeated, genuine threat to capture the same piece counts as perpetual chase. If the target is protected, so that taking it would simply lose material back, repeating is not ruled against the chasing side. Protection is no excuse when the exchange still wins, though: a horse or cannon attacking a chariot is a chase even if the chariot is defended. Threats by the general or a soldier never count.
Why the word 'genuine' does most of the work
The rules are not concerned with the appearance of a threat, only with whether capturing would actually gain something. A repeated approach toward a heavily defended piece, where taking it would simply lose material back, is not the kind of chase the adjudication targets.
Where the hard cases live
Whether chasing a soldier counts, whether a piece that could retreat to safety was really being chased, and how to rule when the chaser's own piece is also under threat are exactly the situations the 110-diagram casebook was built to settle, because no short verbal rule covers them cleanly.
Related questions
Does chasing an undefended piece always count?
Generally yes, if the same piece is threatened on every move and the position truly repeats, unless the chaser is the general or a soldier, or the target is a soldier that has not crossed the river.
Can a player claim their repeated moves were not really chasing?
Yes, and it is adjudicated on the actual position, not on either player's claimed intention.
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