Zi Wei Dou Shu

Zi Wei Dou Shu, “Purple Star Astrology,” is the second most important Chinese system after BaZi. Instead of analyzing the elements, it places stars in the twelve palaces of the chart. The calculator builds the chart by the classical rules and briefly explains the main points.

Calculation

You need the date and time of birth: the Life palace and half of the stars depend on the hour. Longitude and UTC offset are needed only if your city is not on the list. The leap month rule matters only if you were born in such a month.

What the Chart Shows

The twelve palaces, from Life to Parents, each with its own pillar and area of life; the Body palace is marked too.
The fourteen major stars — the Zi Wei and Tian Fu groups — and eighteen minor stars: Wen Chang and Wen Qu, Zuo Fu and You Bi, Tian Kui and Tian Yue, Lu Cun and Tian Ma, the six “malefic” stars, the romance stars and a few more.
The Four Transformations of the birth year — Hua Lu, Hua Quan, Hua Ke and Hua Ji — and the palaces they fall in.
The ju, the chart's “element number,” which determines the position of Zi Wei and the age at which the Major Periods begin.
The Major Periods of ten years each, the current period and the palace of the current year with its Four Transformations.
The Destiny Master and Body Master, the lunar birth date and the time with its corrections.

Below the chart are short interpretations: what the stars in the Life palace mean, where the Body palace is, and which areas the Four Transformations fall in. You can save the chart as a link, print it or add it to your saved charts.

How the Method Works

The chart is a square of twelve sectors, called palaces. Each governs its own area: life, siblings, spouse, children, wealth, health, travel, friends, career, property, well-being, and parents.

Stars are placed in the palaces — not astronomical objects but notional points whose positions are calculated from the date and hour of birth in the lunisolar calendar. The chief among them is Zi Wei, the "Purple Star," which gives the system its name.

There are about a hundred and eight stars, fourteen of which are considered major. The chart is read by which stars land in which palace and what condition they are in.

How the chart is built

Lunar date. The birth time is converted to true solar time, then the date to the Chinese lunar calendar. Months are counted from actual new moons in Beijing time, as in the official calendar.
The Life palace is counted from the Tiger branch: forward by the number of the lunar month and backward by the number of the hour. The Body palace is forward by the same hour.
The ju is the Na Yin element of the Life palace's pillar: Water 2, Wood 3, Metal 4, Earth 5, Fire 6.
Zi Wei is placed by the ju and the lunar day; the other major stars sit at fixed distances from it and from Tian Fu.
The minor stars are placed by the year stem and branch, the month and the hour; the Four Transformations, by the year stem.
The Major Periods begin at an age equal to the ju, counted in Chinese years. For men born in a yang year and women born in a yin year they run clockwise, for everyone else counterclockwise.

We checked the star placement, the Four Transformations, the ju and the periods against the open-source iztro library on four hundred random charts — the results matched completely.

Where schools disagree

Leap month. Some count it as the same month, others as the next one, and others split it in half: up to the 15th day it is this month, after that the next. The last rule is the default; the others can be selected in the form.
The Rat hour from 23:00 to 01:00: whether the day changes at 23:00 or at midnight. The lunar day depends on this, and so does Zi Wei.
The Four Transformations for years with the stems 戊, 庚 and 壬 differ between schools. The calculator follows the “Complete Collection of Zi Wei Dou Shu” and lists the variants if your year is one of these.
True solar time. Many programs build the chart from clock time, without the correction. You can turn it off.

If your program gave a different chart, compare these four settings first.

How It Differs from BaZi

BaZi works with the balance of the five elements and answers the question "What kind of person is this, and what supports them?" Zi Wei works with areas of life and answers the question "What's happening in this particular area?"

Practitioners often use both systems together: BaZi for the overall picture, Zi Wei for specific questions about career, marriage or property.

The second difference is technical: Zi Wei charts are built only with the lunisolar calendar, while BaZi uses either the solar terms or the lunar months, depending on the school. Their boundary dates differ.

An Honest Look at the Method

The system has developed since the Song dynasty and is especially popular in Taiwan and Hong Kong. It is internally consistent, rich and takes a long time to learn: our interpretations are the meanings of individual stars, not a reading of their combinations.

It has as much verifiable support as the rest of astrology — that is, none. We describe it as a cultural phenomenon and as a method for a structured conversation about your life.

Couple Compatibility

Two Zi Wei charts can be compared with each other: Zi Wei Dou Shu couple compatibility shows how each person's chart sees a spouse, who each person turns out to be in the other's chart, where the Four Transformations and love stars land, and which years matter for the couple.

Related in This Section

Frequently asked questions

Why can't the chart be built without a birth time?

The Life palace is counted from the month and hour of birth, and Wen Chang, Wen Qu, Huo Xing, Ling Xing, Di Kong and Di Jie also depend on the hour. Without the hour, not a single palace can be placed, so the calculator asks for the time.

Is an “empty palace” worse than a regular one?

No. If a palace has no major stars, tradition reads it through the opposite palace. An empty Life palace usually describes a flexible person who depends heavily on their surroundings.

Why are the ages in the periods higher than my real age?

Zi Wei counts age the Chinese way: a person is already one year old at birth, and every lunar New Year adds another year. So the Chinese age is one or two years more than the usual one.