BaZi Engine

An open-source (MIT) BaZi - Four Pillars of Destiny - calculation engine, and the free calculator built on it at bazi-atlas.com. It ships with true solar time correction, worldwide birthplace support, an explicit unknown-birth-hour mode, ten gods, luck pillars, compatibility, shen sha, and all 64 I Ching hexagrams across 700+ bilingual pages. Every convention is documented in public, and where classical schools genuinely disagree (late-Zi day switch, LiChun year boundary, luck-pillar start age) both positions are computed instead of one being silently picked. Includes a fixture-locked test suite you can run yourself, and an 85-case differential harness against reference implementations.