紫微斗數
Your Zi Wei Dou Shu chart
Purple Star astrology — twelve palaces, fourteen major stars, and a thousand years of Chinese practice behind it. Your life areas first, the traditional chart when you want it, and the whole calculation shown so you can check it.
Zi Wei does not use the same year as BaZi
This is the single commonest error in Chinese astrology software, and it is invisible when it happens. BaZi begins its year at 立春, Start of Spring, around 4 February. Zi Wei Dou Shu begins its year at 正月初一 — Lunar New Year — which moves, and which is usually a fortnight or so later.
So a birth on 10 February 2026 falls after Li Chun and before Lunar New Year. BaZi reads that year as 丙午. Zi Wei reads it as 乙巳. Both are right, for their own system.
That one character is not cosmetic. It sets the palace stems through 五虎遁, which set the Life Palace stem, which gives the 納音, which gives the Five-Element Bureau, which places 紫微 — and every one of the fourteen major stars hangs off 紫微. It also changes all four of your 生年四化. An engine that borrows BaZi's year does not produce a slightly different chart for these births. It produces someone else's.
This engine never calls the BaZi year function. Where your birth falls in that window, the calculation panel shows you both values side by side and flags the difference.
The hour matters more here than anywhere else
In most systems an unknown birth time costs you some detail. In Zi Wei it costs you the chart. Your Life Palace is placed from the lunar month and the birth hour together, and the Life Palace determines the Bureau, which determines where 紫微 goes, which determines all fourteen major stars.
So without a time this page does not show you a noon chart and hope. It builds all twelve hour charts — plus the late-子 case, where a birth between 23:00 and 23:59 rolls onto the next lunar day and can produce a thirteenth distinct result — and tells you which conclusions survive all of them and which do not.
Some things genuinely do survive. Which four stars carry your 生年四化 depends only on the birth year, so it holds regardless of the hour. Which palaces those transformations land in does not — and reporting the first as confirmed while quietly letting the second move is the kind of half-truth this page is built to avoid.
One school, stated
Zi Wei Dou Shu has no single universal implementation. Lineages differ on the year boundary, the late-子 rule, leap months, which auxiliary stars are included, star brightness and even parts of the 四化 table. Mixing rules from different schools produces a chart that is internally inconsistent and looks perfectly normal.
This engine implements one — 三合 / San He — and every convention it uses is printed in the calculation panel. Where schools are known to disagree, such as the 庚-year 化科, the choice is recorded in the configuration rather than hidden.
One thing is deliberately absent: star brightness (廟旺利陷). It is a table of nearly two hundred values that differs between lineages, and rather than ship a half-remembered version that would look authoritative and be wrong in places nobody could check, the engine reports it as not configured and says so.