Tools · 紫微斗数
Zi Wei Dou Shu Calculator
Bazi asks what you are made of. Zi wei dou shu asks where things happen. It takes the same three facts, a date, an hour and a sex, and builds something quite different out of them: a ring of twelve palaces, one each for marriage, money, career, health, children and the rest, with named stars dropped into them by rule. The star that goes in first is Zi Wei, the pole star the whole sky turns around, and everything else is positioned from where it lands. This calculator casts the natal chart and shows its working, step by step.
Cast your chart
Three facts. The hour is not optional here.
You will get the twelve-palace chart, your bureau, all fourteen major stars with the four transformations marked, your decade limits, and the derivation in the open.
What is zi wei dou shu?
Zi wei dou shu, 紫微斗数 (zǐwēi dǒushù), is a system of Chinese fate analysis that places named stars into twelve palaces to describe a life. The name is worth unpacking, because it is a set of directions rather than a title: Zi Wei is the pole star and the celestial enclosure around it, the sky's imperial palace; dou is the Dipper, the seven stars that swing around that pole all night and point at it; and shu is counting. The purple star, counted out by the Dipper.
The stars are not the astronomical objects. Only a handful of the names correspond to anything a telescope would find, and the system does not use their positions in the sky on your birthday. They are abstract markers moved by arithmetic, which is why a chart can be cast from a lunar date on paper with no observation at all. Treat them as the tradition does: as a vocabulary of fourteen dispositions and twelve departments of a life, and a set of rules for putting one into the other.
The system is conventionally attributed to Chen Tuan, a tenth-century Daoist recluse of Mount Hua, though the surviving textual tradition is much later and the attribution is the usual kind: a founder assigned backwards to give a method a lineage. What is not in doubt is that it has been the main rival to bazi in Chinese practice for centuries, and that most practitioners who use one can read the other.
How the chart is built
Five steps, each of them a rule rather than a judgment. This is the whole placement procedure, and it is the same one running inside the calculator above.
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Step 1 · the Life Palace
Start at the Yin branch, count forward to your lunar birth month, then count backward by your birth hour. Where you stop is the Life Palace, and everything else is labeled from it. Counting forward by the hour instead gives the Body Palace, read as the half of a life a person builds rather than arrives with.
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Step 2 · the other eleven palaces
From the Life Palace, the remaining names run backward around the ring in fixed order: siblings, spouse, children, wealth, health, travel, friends, career, property, fortune, parents. No choice is involved. Where your Life Palace lands decides which branch holds your marriage and which holds your money. That list of twelve is older than this system and is not unique to it: physiognomy lays the same twelve palaces over a face instead of over a ring of branches.
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Step 3 · the five element bureau
Each palace gets a heavenly stem, deduced from your birth year by the Five Tigers rule. The stem and branch of the Life Palace together make a pair, that pair has a nayin element, and the element gives the bureau: Water 2, Wood 3, Metal 4, Earth 5 or Fire 6. The number matters twice over, in the next step and in the decade limits.
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Step 4 · the Emperor, then everyone else
Divide your lunar birth day by the bureau number. If it does not divide evenly, add the smallest number that makes it, and remember what you added. The quotient counts you forward from the Yin branch; then you move again by the number you added, forward if it was even and backward if it was odd. That is where Zi Wei goes. Five stars follow it backward around the ring; the Treasury star mirrors it across the chart, and eight more follow the Treasury forward.
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Step 5 · the four transformations
Your birth year's stem selects four stars already on the chart and modifies them: prosperity, power, repute, affliction. Nothing moves. Four stars simply acquire a second reading, and practitioners spend most of their attention on where those four landed.
The twelve palaces
Every chart has all twelve, in this order, running backward from the Life Palace. They are departments of a life, not predictions about it.
| # | Palace | What it covers |
|---|---|---|
| 1 | Life 命宫 | character, and the shape of the whole chart |
| 2 | Siblings 兄弟 | brothers, sisters, peers |
| 3 | Spouse 夫妻 | marriage and the partner |
| 4 | Children 子女 | children, and what you produce |
| 5 | Wealth 财帛 | money as it moves |
| 6 | Health 疾厄 | the body and its weak points |
| 7 | Travel 迁移 | movement, and life away from home |
| 8 | Friends 交友 | colleagues, subordinates, the crowd |
| 9 | Career 官禄 | office, standing, the work itself |
| 10 | Property 田宅 | land, house, what is held |
| 11 | Fortune 福德 | inner life, appetites, ease |
| 12 | Parents 父母 | parents, elders, authority |
The fourteen major stars
Six of them are positioned from Zi Wei and eight from the Treasury star, which is why the two families always sit in the same relative arrangement. Each description below is character rather than forecast: what the star is held to be like when it turns up in a palace, in the terms the manuals use.
- the Emperor 紫微 Zǐwēi
- The pole star, and the one every other star is positioned from. Read as command, dignity and a certain need to be deferred to; on its own, prone to standing on ceremony with nobody to govern.
- the Strategist 天机 Tiānjī
- Motion and calculation. Quick, restless, good at plans and at seeing three moves ahead, and inclined to change the plan again before the first one has finished.
- the Sun 太阳 Tàiyáng
- Giving out. Public-facing, generous, hard to keep private; strongest in the daylight branches and said to spend itself on people who do not notice.
- the General 武曲 Wǔqǔ
- Metal, decisiveness and money as a thing you go and get. Blunt, effective, not warm; the star of execution rather than persuasion.
- the Child 天同 Tiāntóng
- Ease and appetite. Contented, sociable, slow to fight; read as the star that gets what it wants late, having enjoyed the wait more than most.
- the Enforcer 廉贞 Liánzhēn
- Rules and their enforcement, and the passions underneath. The most double-edged of the fourteen: principle at its best, obsession at its worst.
- the Treasury 天府 Tiānfǔ
- The treasury: storing, holding, administering. Steady and conservative where the Emperor is commanding, and the reason the two are read as a pair.
- the Moon 太阴 Tàiyīn
- Taking in. Private, retentive, attentive to detail and to property; the counterweight to the Sun, and strongest in the night branches.
- the Wolf 贪狼 Tānláng
- Wanting. Charm, appetite, versatility and a taste for the new; the tradition links it to both social skill and excess, and does not apologize for either.
- the Great Gate 巨门 Jùmén
- The mouth. Argument, scrutiny, doubt, and a real gift for saying the thing nobody else will; also the star most often blamed for trouble that started as a remark.
- the Minister 天相 Tiānxiàng
- The minister who serves. Fair-minded, presentable, dependent on who it serves next to; read almost entirely by its neighbors.
- the Elder 天梁 Tiānliáng
- The elder. Protection, seniority, an instinct to arbitrate, and a certain moralising streak that the older manuals mention with affection.
- the Seven Killings 七杀 Qīshā
- Decisive severance. Independent, hard-working, unsentimental about endings; the tradition treats it as the star of a life with sharp edges in it.
- the Army-Breaker 破军 Pòjūn
- Breaking in order to rebuild. Disruptive, pioneering, expensive; nothing it touches stays in its previous shape.
Four support stars come with them, because the transformations need them as targets: Literary Brilliance, Literary Arts, the Left Assistant, the Right Assistant.
The four transformations
Four stars per chart, chosen by the birth year's stem. They do not move anything; they change how their star reads in the palace it already occupies, and they are where most practitioners look first.
Prosperity 化禄
the star pays out here
Power 化权
the star gets authority here
Repute 化科
the star brings a name here
Affliction 化忌
the star sticks and snags here
A worked example
A birth on 17 May 1990 at 2pm, male. That is lunar month 4, day 23 of the year 庚午, in the 未 hour (13:00–15:00). Counting forward 3 from the Yin branch and back 7 for the hour puts the Life Palace at 戌, whose stem-and-branch pair gives the bureau 土五局 (Earth 5). Dividing day 23 by 5 places the Emperor at 申 and therefore the Treasury at 申. The Life Palace ends up holding the Wolf, and the decade limits run forward from age 5.
The four transformations for a 庚 year land like this: the Sun takes prosperity in the Health palace; the General takes power in the Travel palace; the Moon takes repute in the Siblings palace; the Child takes affliction in the Friends palace.
Every number in that paragraph is computed by the same engine that runs the calculator, at build time, so this example cannot drift out of step with the tool.
What this calculator does not do
It places the natal skeleton and stops there. A practitioner's chart carries several dozen minor stars over the fourteen major ones, plus decade, annual, monthly and daily layers stacked on top of the natal one. We place the twelve palaces with their stems, the bureau, the fourteen majors, the four supports the transformations need, the transformations, and the decade limits. Nothing here contradicts a fuller chart; there is simply less on it.
It does not read your chart back to you as a fortune, because that is a judgment call made by a person who has looked at all of it at once, and a paragraph generated from one star in one palace would be worth exactly what it cost. What you get instead is an accurate chart with every placement rule visible, which is the thing that is genuinely hard to find in English and the thing you need before any reading is possible.
And it tells you when the schools disagree. Two places on this chart are genuinely contested rather than settled: what to do with a birth in an intercalary month, and which star receives the repute transformation in a Geng year. The result page names both where they apply to you, instead of picking one and going quiet.
Questions people ask
What is zi wei dou shu?
Zi wei dou shu is a Chinese system of fate analysis that arranges a chart of twelve palaces around a fixed ring of twelve earthly branches, then places a set of named stars into those palaces from your lunar birth date and hour. The name means "the purple star of the northern dipper counted out," after Zi Wei, the pole star, which is placed first and from which almost every other star is positioned. It is the main alternative to bazi, the four pillars, and the two are read together as often as separately.
What is the difference between zi wei dou shu and bazi?
Same birth data, different machinery, different picture. Bazi takes your birth moment as four stem-and-branch pillars and reads the balance of the five elements between them, so it is fundamentally about proportion. Zi wei dou shu takes your lunar month, lunar day and birth hour and uses them to place named stars into twelve named areas of life, so it is fundamentally about location: which star landed in the palace of marriage, of career, of money. Bazi tells you what you are made of; zi wei dou shu tells you where things happen. The two systems compared at length, including which one has the older textual record, is on our bazi-versus-zi-wei page.
Do I need my exact time of birth for a zi wei dou shu chart?
Yes, and unlike a kua number there is no way around it. The birth hour is one of only three inputs the placement uses, and it moves the Life Palace directly: two births on the same day two hours apart get Life Palaces one branch apart, which shifts all twelve palace labels around the ring and changes which star governs your marriage, your money and your career. If you do not know your hour, a chart cast on a guess is not a rough answer. It is a different person’s chart.
What is the five element bureau?
The bureau, wu xing ju, is a number from two to six attached to your chart: Water 2, Wood 3, Metal 4, Earth 5 or Fire 6. It comes from the nayin element of the Life Palace’s own stem-and-branch pair, and it does two jobs. It sets where the Emperor star falls for your birth day, which cascades into the position of all fourteen major stars, and it sets the age at which your decade limits begin, so a Water 2 chart starts its first decade at two years old and a Fire 6 chart at six.
What are the four transformations?
Four of the stars on your chart are singled out by your birth year’s heavenly stem and given a modifier: hua lu, prosperity; hua quan, power; hua ke, repute; and hua ji, affliction. They are read as the live wires of a chart, because they mark where the tradition expects a star to pay out, take charge, be recognized, or snag. Which star gets which modifier is fixed by a ten-row table, one row per stem, and our calculator prints all four with the palace each landed in.
Was I born in a leap month?
If you were, the schools disagree about your chart and we tell you so on the result page rather than picking quietly. The Zhongzhou convention treats an intercalary fourth month as month four; the Qintian convention splits it, counting the first fifteen days as the third month and the rest as the fourth. Since the month number drives the Life Palace, the two rules can produce charts that differ by a whole palace. We compute the first and show you what the second would have done.
Is this the whole chart?
No, and we would rather say so. A traditional chart carries dozens of minor stars on top of the fourteen major ones, plus annual and decade layers stacked over the natal one. Our calculator places the twelve palaces with their stems, the five element bureau, the fourteen major stars, the four support stars needed to complete the transformations, the four transformations themselves, and the decade limits. That is the natal skeleton every school agrees on. Everything a practitioner would add is additional, not contradictory.
The rest of the birth chart
The same three facts drive more than one system here. Your bazi chart reads your birth moment as four pillars and weighs the elements between them. Your kua number turns your birth year into a trigram and eight compass directions. And if you have your birthday only as a lunar date, or only as a Gregorian one, the calendar converter moves it either way, leap months included.