System
What is Liu Yao?
Liu Yao (六爻) is East Asian horary: three coins, six tosses, a hexagram read through the Six Relatives. The question picks the yong shen — the line that is the thing asked about — and the reading asks whether time supports or drains that line. The I Ching asks what the moment is; Liu Yao asks the outcome of this specific thing. Lightweight mode uses the day’s element only. A date is never turned into a hexagram.
What job does it do?
Ask, When. Epistemic badge: verdict.
What is traditional, and what is our interpretive layer?
Traditional mechanic, tables, and named sources live in the vault file Celestial-LiuYao.md. Interpretive voice — the 12 Inner Alignment Dimensions and the wording of advice — is Celestial Nexus. We do not flatten the two.
What is it not?
It is not a tropical Western natal wheel. It is not a fake cast from a date unless the engine is honestly computational. Harm-capable historic verdicts are documented, not performed.