BaZi Chart Casting Terms: Where the Pillars Come From, Solar Terms and Hours

BaZi runs on the solar-term calendar: the year starts at the Start of Spring and each month at its own solar term, and the hour needs true solar time and the Zi hour rule. This group collects the terms you meet while casting a chart.

Index of this group

• Calculating a BaZi chart
• Year pillar
• Month pillar
• Day pillar
• Hour pillar
• Month command
• Solar term boundary
• True solar time
• Early Zi hour
• Daylight saving time
• Birth time correction
• Three-pillar chart
• Estimating the birth hour
• Conception Pillar
• BaZi Life Palace
• BaZi Body Palace

16 terms

Calculating a BaZi chart 排八字

Calculating a BaZi chart means converting the year, month, day and hour of birth into a stem-branch pair each, giving four pillars and eight characters. The year turns at the Start of Spring, the month at solar terms. Read more →

Year pillar 年柱

The year pillar is the first pillar of a BaZi chart. It changes at the Start of Spring; after that moment, the remainders of (Gregorian year − 4) divided by 10 and by 12 give its stem and branch. Read more →

Month pillar 月柱

The month pillar is the second pillar. Its branch is set by the twelve jie solar terms (the Start of Spring begins Yin, the Awakening of Insects Mao…), and its stem comes from the year stem by the Five Tigers rule. Read more →

Day pillar 日柱

The day pillar is the third pillar, and its stem is the Day Master. The day's stem-branch pair moves one step through the sixty Jiazi each day, so it can be worked out by counting from a date whose pillar is known. Read more →

Hour pillar 時柱

The hour pillar is the fourth pillar of a BaZi chart. Its branch is set by the two-hour period of birth, and its stem comes from the day stem by the Five Rats rule. Read more →

Month command 月令

The month command (yue ling) is the Earthly Branch of the month pillar, also called the ti gang. It carries the season’s ruling energy and is the main reference for judging Day Master strength and choosing the chart structure. Read more →

Solar term boundary 節氣交界

A solar term boundary birth is one close to the moment a jie term changes. BaZi changes the year at the Start of Spring and the month at each jie term, so for these births the exact time decides the month pillar, sometimes the year. Read more →

True solar time 真太陽時

True solar time is local time measured by the sun, with noon when it crosses due south. It equals standard time plus the longitude offset (four minutes per degree) plus the equation of time. Read more →

Early Zi hour 早子時

The Early Zi hour is 00:00–00:59 and the Late Zi hour is 23:00–23:59. Because the Zi hour spans midnight, schools differ on whether a Late Zi birth takes that day's or the next day's day pillar. Read more →

Daylight saving time 夏令時間

Daylight saving time sets the clocks an hour ahead in summer. If you were born under it, your birth certificate shows a clock time an hour ahead of standard time, so subtract that hour before casting a BaZi chart. Read more →

Birth time correction 出生時間校正

Birth time correction turns the clock time on a birth certificate into the time a BaZi chart uses: take off daylight saving, convert to true solar time for the birthplace, then check the Zi-hour day change and solar term boundaries. Read more →

Three-pillar chart 三柱八字

A three-pillar chart is a BaZi chart cast from the year, month and day pillars alone, six characters, when the birth hour is unknown. The Day Master and month branch are certain; strength and favorable elements are not. Read more →

Estimating the birth hour 推定時辰

Estimating the birth hour means using records, a remembered time of day and past life events to narrow the twelve possible hours when the birth time is unknown. The result is only ever "more likely," never certain. Read more →

Conception Pillar 胎元

The Conception Pillar (tai yuan, 胎元) is an auxiliary BaZi pillar found by moving the month stem one step and the month branch three steps forward, roughly the month pillar nine months before birth. Read more →

BaZi Life Palace 八字命宮

The BaZi Life Palace (ming gong) is a palace pillar derived from birth month and hour: add both numbers, counted from Yin, subtract the sum from 14 or 26 to get the branch, and take the stem from the year stem. Read more →

BaZi Body Palace 八字身宮

The BaZi Body Palace (shen gong) is a second palace from birth month and hour: count the month from Yin and the hour from Zi, add them, subtract 12 if over 12, and take the stem from the year stem. Read more →

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