In a perpetual chase dispute, does the burden of proof fall on the claimant or the accused player?
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
The player making the claim. A perpetual chase draw is not the default outcome of a repeating position; it has to be actively established that the chase is happening without variation and that the chasing player genuinely had another reasonable option available. The player raising the claim carries that burden, not the player accused of chasing.
Why the claimant carries this responsibility
Since chase depends on judging intent and available alternatives rather than a simple objective fact, treating every repeated attacking pattern as presumptively illegal would penalise entirely normal, aggressive play. Requiring the claimant to actually demonstrate the pattern keeps the burden where the uncertainty genuinely lies.
What a claimant typically needs to show
In practice this means pointing to the recurring position, the specific piece being repeatedly attacked, and, crucially, a reasonable alternative move the chasing player had and declined to make. A claim that only shows the repetition itself, without addressing whether an alternative existed, is usually not enough on its own.
Related questions
Does the same burden apply to perpetual check claims?
Less so in practice, since check is objectively verifiable from the position alone, there is far less room for genuine dispute over the underlying facts.
What happens if the evidence is genuinely unclear either way?
The arbiter rules using the casebook and their own judgement; an unresolved case does not default automatically to either side.
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