BaZi (Four Pillars)

Chinese 'eight characters' astrology: the birth moment expressed as four pillars — year, month, day, and hour — each a Heavenly Stem paired with an Earthly Branch, read through the five elements.

BaZi (八字, 'eight characters') or the Four Pillars of Destiny reads a birth moment as four stem-and-branch pairs. Each pillar joins one of ten Heavenly Stems with one of twelve Earthly Branches, drawn from the sixty-term sexagenary cycle that has counted Chinese years, months, days, and hours since antiquity. Eight characters in total — hence the name. BaZi runs on the solar-term calendar, not the lunar one. The year turns at Lichun (立春, the start of spring, when the Sun reaches 315°, around February 4), and the month is set by the 24 solar terms — both fixed by the Sun's position, so they are ordinary astronomy. The day pillar is the continuous sexagenary day count, and the hour pillar comes from the two-hour period of birth. The stem of the day pillar is the Day Master — the 'self', the reference point the rest of the chart is interpreted around. The pillars are exact arithmetic and can be checked against known dates. Everything read into them — the balance of the five elements, the Ten Gods, the luck pillars — is interpretive tradition, not a measured property of a person.

Not: BaZi is not a prediction of events and not a verdict on a life. It is a symbolic profile built from calendar and solar-term arithmetic. It is also not the Chinese zodiac reduced to a birth-year animal — that animal is only one of the eight characters.

The pillars are computed exactly; near a boundary (midnight for the day, or a solar term for the year/month) a small change in birth data can shift a pillar. The elemental and Ten Gods meanings are traditional convention, not demonstrated effects. Traditionally BaZi also uses true solar time (a longitude correction), a refinement this reading notes where it applies.