Ba Zi

The Four Pillars are written in the sexagenary cycle, the ganzhi, formed by pairing the ten Heavenly Stems with the twelve Earthly Branches. The stems and branches turn together like two meshed wheels, and because a yang stem can only meet a yang branch and a yin stem only a yin branch, the pairing yields sixty combinations rather than a hundred and twenty. This run of sixty, the jiazi, names years, months, days and hours alike.

A birth produces four such pairs, the four pillars:

• the year pillar, set by the solar year, which turns at the Start of Spring in early February, not at lunar new year;
• the month pillar, set by the solar term the birth falls in;
• the day pillar, counted continuously through the sexagenary day-count;
• the hour pillar, set by the double-hour of birth.

The stem of the day pillar is the day master, the character that stands for the person. Everything else in the chart is read as it relates to this one stem: what strengthens it, what drains it, what it controls and what controls it. Each of the sixty pairs also carries a nayin, a five-agent melody named in poetic images such as metal-in-the-sea or fire-in-the-hearth, a further layer of element assignment used in some methods of the reading.

An Earthly Branch is not the simple animal of the popular zodiac. Each branch stores one, two or three Heavenly Stems within it, the hidden stems or canggan, ranked as principal, middle and residual qi. The true balance of the five agents in a chart is read from the four visible stems together with these hidden stems, which is why two people born in the same animal year can have entirely different destinies: the concealed agents differ with the month and the hour.

Against the day master, every other stem in the chart, visible or hidden, plays one of ten relational roles, the ten gods, shi shen. They fall into five pairs, one of each polarity:

• Companions, the Friend and the Rob Wealth, stems of the day master's own agent, standing for peers, rivals and the self's own strength.
• Output, the Eating God and the Hurting Officer, the agent the day master produces, standing for expression, talent and what one creates.
• Wealth, the Direct Wealth and the Indirect Wealth, the agent the day master controls, standing for money, possessions and, by tradition, the wife.
• Officer, the Direct Officer and the Seven Killings, the agent that controls the day master, standing for authority, discipline, career and pressure.
• Resource, the Direct Resource and the Indirect Resource, the agent that produces the day master, standing for support, learning, mother and shelter.

Reading a Four Pillars chart is largely the work of judging which of these ten gods are strong, which are absent, and what the day master most needs or most has in excess, then timing that judgement against the luck pillars, the ten-year cycles counted out from the month pillar.