What is my day master?

A BaZi chart has four pillars: one each for the year, the month, the day and the hour of birth. Each pillar is a pair of characters, a heavenly stem on top and an earthly branch below, which is why the chart is also called the eight characters.

The stem of the day pillar is the one the whole chart is read from. Traditional texts treat it as the person themself; every other character is described by how it relates to that stem, for example whether it feeds it, drains it or holds it in check. Because it stands for you, English BaZi books call it the day master (日主) or day element (日元).

There are ten stems, so there are ten day masters: the five elements, each in a yang form and a yin form. Yang Wood is a tall tree, Yin Wood is a climbing vine; Yang Water is a river, Yin Water is dew. Each has its own page in the guide to the ten types.

Chinese calendar days carry a stem-branch name of their own, counted in a cycle of 60 that runs on from day to day without regard to months or years. The count has run without a break since at least 720 BCE. Each day the stem moves one step through the ten stems and the branch moves one step through the twelve branches.

Ten and twelve first line up again after 60 steps, so the same pair returns every 60 days. A yang stem only ever meets a yang branch and a yin stem a yin branch, which is why there are 60 pairs and not 120.

The stem alone repeats every 10 days. Your day master is therefore set by where your birthday falls in a ten-day rhythm, not by the month or the season. Roughly one person in ten shares your day master; what makes charts differ is everything around it: the month you were born in weighs most, then the year and the hour.

Most people know the Chinese zodiac: the Rat, the Ox, the Tiger and the rest. That animal is the earthly branch of your year pillar. It is shared by everyone born in the same BaZi year, which starts at the beginning of spring (Lichun, around February 4), not on January 1 or at Chinese New Year.

BaZi as it is practised today reads the chart from the day stem instead. Older methods read a chart from the year; the Ziping school, traditionally traced to the Song dynasty, made the day stem the centre, and that is the method most BaZi books follow. The year animal still appears in the chart, but as one of eight characters, not as the centre. Two people born in the same year share an animal yet usually have different day masters, and two people born ten days apart share a day master yet sit in different months, which changes how strong that element is.

Take someone born on March 14, 1992. The engine gives that date the day pillar Ji Chou (己丑). Its stem, Ji (己), is Yin Earth, so this person's day master is Yin Earth, the Garden Soil.

The same chart has the year pillar Ren Shen (壬申), so in the popular zodiac this person is a Monkey. The Monkey is shared by everyone born in that BaZi year; the Yin Earth day master by everyone born on the same day of the ten-day rhythm.

The ten days from March 14, 1992 run through all ten day masters in order, then start again:

The day pillar changes at midnight in local solar time, the time the sun gives at your birthplace. That can differ from the clock by tens of minutes, and by two hours or more in some places because of daylight saving time and wide time zones. A birth at 23:30 on the clock can already be after solar midnight, or a birth at 00:30 still before it.

Schools also differ on the hour from 23:00 to midnight. Thaat keeps it on the same date: someone born at 23:40 solar time keeps that date’s day pillar, and only the hour pillar belongs to the next day. Other schools start the new day at 23:00.

So if you were born within about two hours of midnight, enter your birth time and city in the full calculator, which converts your time to local solar time before it picks the day.

Your day master names your core temperament in this framework: how you take in pressure, what you tend to give, what keeps you steady. The guide for each type covers strengths, blind spots and what supports it.

It is one stem out of eight characters. The full free chart on the home page adds your four pillars and your five-element balance, which shows whether your day master stands strong or light in your own chart. That needs your birth time and place as well as the date.