BaZi (Four Pillars)
The Four Pillars system at the centre of Chinese astrology: how a chart is built from stems and branches, and how its Day Master, Ten Gods and symbolic stars are read.
BaZi (八字, bāzì) — the Four Pillars of Destiny — is the oldest and most widely practised system of Chinese natal astrology, and the centre of this section. The name means "eight characters", and that is exactly what a chart is: the year, month, day and hour of birth, each written as a Heavenly Stem paired with an Earthly Branch, for eight characters in four columns. Everything else in the method is a way of reading those eight.
The chart
A BaZi chart is built pillar by pillar from the calendar. Each pillar carries a stem above and a branch below, and the four pillars speak to different layers of a life — ancestry and early context in the year, upbringing and career in the month, the self and the partner in the day, and late life and legacy in the hour. The single most important character is the Day Stem, the Day Master, which stands for the person themselves and against which every other character is read.
Stems and branches
The two cycles behind the chart each have a group of their own here. The Ten Heavenly Stems are the visible, yang half — the Five Elements split into Yin and Yang — and the Twelve Earthly Branches are the hidden, yin half, each carrying its own concealed stems and its web of combinations and clashes. Together they turn through the sixty-year Jiazi cycle, which is also how the calendar names its years.
Reading the chart
Interpretation begins with the balance of the Five Elements around the Day Master and with the Ten Gods — the ten relationships every other character bears to the self. On top of that layer sit the symbolic stars, the Shen Sha that the texts watch for, and the ten-year luck cycles that describe how a life rises and falls over time. The articles assume no prior study and build in that order: chart first, then relations, then the finer marks.
BaZi and the rest of the section
BaZi is not the only system of Chinese astrology, and this section is honest about the difference. Zi Wei Dou Shu reads the same birth data into a twelve-palace chart of named stars rather than into eight characters, and the two are often consulted together. The vocabulary they share — the stems, the branches, the Five Elements — is the same, which is why the fundamentals are worth learning once, wherever you start. To cast a chart from your own birth data, the BaZi calculator does the arithmetic.