Zi Wei Dou Shu basics: the twelve palaces and the major stars

Zi Wei Dou Shu (紫微斗數), often called Purple Star astrology, is the other great chart system of Chinese astrology besides BaZi. Tradition attributes it to the tenth-century Daoist Chen Tuan (陳摶). Most of its "stars" are not stars you can see in the sky but calculated points with traditional names. Where BaZi reads eight characters, Zi Wei lays out a board of twelve palaces and places more than a hundred stars in them.

What the chart is cast from

Zi Wei works from the lunar date (year, month and day) and the two-hour period of birth (時辰). It cannot be cast without the hour, so our calculator asks for it. A few conventions matter:

• The year starts at Lunar New Year (正月初一), not at the Start of Spring as in BaZi. If you were born between the two, your Zi Wei year and your BaZi year differ, and the chart says so.
• Leap months (閏月): days 1 to 15 count as that month, days 16 onward as the next. This is one of several conventions in use.
• The late Zi hour (23:00 to 24:00) follows the same setting as our BaZi calculator: by default the chart moves to the Zi hour of the next day.
• Clock time is converted to true solar time when the birthplace is known, because the hour decides where the palaces fall.

The twelve palaces

The board has twelve cells, one per Earthly Branch, always in the same positions. What changes from chart to chart is which theme of life sits in which cell. Starting from the Life Palace and running counterclockwise, the palaces always come in this order (with the site's English names):

• Life (命宮): the person and their temperament, the centre of the chart
• Siblings (兄弟): brothers, sisters and close peers
• Partner (夫妻): partnership and marriage
• Children (子女): children, and by extension what you nurture
• Wealth (財帛): how you earn and handle resources
• Wellbeing (疾厄): pace, rest and habits; here it is read only as self-care, never for health predictions
• Travel & outside world (遷移): how you meet the world away from home
• Friends (僕役, also 交友): friends, colleagues and networks
• Career (官祿): work and public role
• Home & property (田宅): home, family base and surroundings
• Fortune & spirit (福德): inner life, enjoyment and peace of mind
• Parents (父母): parents, elders and mentors

The Life Palace and the Body Palace

The Life Palace is found with a rule every student learns: start at the 寅 cell for the first lunar month, count forward to the birth month, then count backward from there to the birth hour. Counting forward to the hour instead gives the Body Palace (身宮), which falls on one of the twelve palaces and adds a second focus. The palaces' stems follow from the year stem, and the stem and branch of the Life Palace set the chart's five-element class (五行局), from water 2 to fire 6. That number helps place the 紫微 star and sets the age at which the first ten-year period begins.

The fourteen major stars

Fourteen stars carry most of a reading. They come in two groups:

• The Zi Wei group: 紫微 Purple Star, 天機 Heavenly Secret, 太陽 Sun, 武曲 Martial Music, 天同 Heavenly Harmony, 廉貞 Pure Integrity.
• The Tian Fu group: 天府 Heavenly Treasury, 太陰 Moon, 貪狼 Greedy Wolf, 巨門 Great Gate, 天相 Heavenly Minister, 天梁 Heavenly Beam, 七殺 Seven Killings, 破軍 Army Breaker.

紫微 is placed from the lunar day and the five-element class, and the rest of its group follows at fixed distances. 天府 is placed as its mirror image, and its group follows in turn. A palace can hold one major star, two, or none; an empty palace borrows the stars of the palace opposite. Each star also has a brightness (廟 旺 得 利 平 不 陷, strongest to weakest) that depends on the cell it stands in. Dozens of minor stars, from helpers such as 左輔 and 右弼 to harsher ones such as 擎羊 and 陀羅, add colour around them.

The Four Transformations

The birth-year stem "transforms" four stars. These Four Transformations (四化) are among the most-watched features of a chart:

• 化祿: flow and abundance
• 化權: authority and drive
• 化科: recognition and refinement
• 化忌: obstruction, the place where attention gathers

For a 甲 year, the common tables give 廉貞 化祿, 破軍 化權, 武曲 化科 and 太陽 化忌. The tables differ between schools, most famously for 庚 years; the site uses the widely used standard set (通行版), not that of the 中州派 school. Each ten-year period and each year brings its own set of four as well.

Ten-year periods

Life is read in ten-year steps called 大限. The first begins in the Life Palace at the age set by the five-element class, counted as nominal age (虛歲), and the steps then move round the board: forward for a man born in a yang year or a woman born in a yin year, backward otherwise.

What a Zi Wei chart is for

A Zi Wei chart is a map of themes: which areas of life sit together, which stars colour them, where the transformations draw attention. It is a tool for reflection. It does not settle what will happen, and on this site it is not used for health, legal or financial questions.

Placed by the calculator

The board, every star, each brightness and the transformations are placed by code from your birth data, using the conventions listed on the chart. The AI writes about the finished board and cannot move a star.