Chinese (BaZi / 四柱)
The Four Pillars of Destiny, derived from the true solar terms — not the pop "zodiac animal," but the calendar mathematics underneath it.
Solar-lunar · Four Pillars, ten heavenly stems, twelve earthly branches
How the math differs
BaZi (八字, “eight characters”) is a solar-lunar calendar system, not the pop animal zodiac. Each of the Four Pillars — year, month, day, hour — is a pair of one heavenly stem and one earthly branch.
The month pillar is set by the true solar terms (jiéqì): the year turns at Lìchūn and each month boundary is the instant the Sun reaches a specific ecliptic longitude, computed from the ephemeris rather than a fixed date.
The day pillar advances on a continuous 60-day sexagenary cycle, and the hour pillar follows from the day stem — so the full chart is arithmetic over an exact astronomical calendar.
What you can compute
Four Pillars (year/month/day/hour)
Stem–branch pairs from true solar terms
Solar-term boundaries
Month turns fixed by the Sun’s ecliptic longitude
Ten stems · twelve branches
Sexagenary cycle resolved to the birth instant
See what the engine already computes
This tradition is on the roadmap. Start with a live system today from the same open-source, arc-second ephemeris core.