General concepts

Zi Wei Dou Shu (Purple Star Astrology)

Also known as: zi wei dou shuziwei dou shuzi weiziweitzu wei dou shuzi wei dou shu calculatorziwei calculatorzi wei chartziwei chartzi wei dou shu chartpurple star astrologypurple starpurple star chartpurple star astrology calculatoremperor star astrologychinese astrology chartchinese birth chart紫微斗數紫微斗数紫微十二宮十二宫命宮命宫身宮身宫五行局四化化祿 化權 化科 化忌tu vitu vi dau sobazi

Zi Wei Dou Shu (紫微斗數), "Purple Star Astrology" or "Emperor Star Astrology", is a Chinese tradition that places stars in twelve palaces of a square chart, calculated from the lunar date and the hour of birth. It is a symbolic system and a cultural tradition, not a science.

Zi Wei Dou Shu (紫微斗數), usually shortened to Ziwei, is a Chinese tradition often called Purple Star Astrology. Instead of the eight characters of BaZi, it draws a square chart of twelve palaces and places stars in them. The name comes from the Zi Wei star, the "Purple Star" that stands for the emperor, and from the Dou, the "Dipper" of the northern sky. The method is traditionally attributed to the Song-era Taoist Chen Tuan (陳摶), and it was set down in classic texts such as the Zi Wei Dou Shu Quan Shu (紫微斗數全書). It is popular in Taiwan, Hong Kong, Singapore and Malaysia. Like every tradition of this kind, it is a symbolic system and a cultural tradition, not a science, and what follows describes how it reads a chart, never what will happen to anyone.

AstroSensus calculates it from the date, the time and the place of birth. The time is required, because the Life palace depends on the hour: without it there is no Zi Wei chart. First the civil date at the birthplace is turned into the Chinese lunisolar date, where each month begins on the day of the new Moon, in China time (UTC+8), as in the published Chinese calendar. The year's stem and branch change at the lunar New Year, not at Li Chun as in BaZi. In a leap month, days 1 to 15 count as the month itself and days 16 onward as the next month; schools differ here, and the result names the rule that was used. The hour is one of twelve double hours, the Zi hour starting at 23:00. By default the day changes at 00:00, so a birth between 23:00 and 23:59 keeps its date, and an option lets the day change at 23:00. A further option uses the apparent solar time of the birthplace.

The chart is the twelve palaces, running from the Life palace (命宮) backwards through the branches: Life, Siblings, Spouse, Children, Wealth, Health, Travel, Friends, Career, Property, Fortune and Parents. The Life palace is found by counting from the Yin branch forward to the lunar month and then back by the hour. The Body palace (身宮) is counted forward by the hour and falls on one of six palaces, which is then marked. Each palace has an Earthly Branch and receives a Heavenly Stem by the "five tigers" rule from the year's stem. The Five Element Bureau (五行局) comes from the Na Yin of the Life palace and is a number, Water 2, Wood 3, Metal 4, Earth 5 or Fire 6; it places the Zi Wei star together with the lunar day.

Fourteen main stars follow, in two groups: the Zi Wei group and the Tian Fu group. Fourteen auxiliary stars are added, supportive ones such as Wen Chang, Wen Qu, Zuo Fu and You Bi, and difficult ones such as Qing Yang, Tuo Luo, Huo Xing and Ling Xing. Each star carries one of seven brightness grades, from 廟 to 陷. The Four Transformations (四化) come from the stem of the birth year, and the ten-year periods (大限) start at the bureau number. The hundred or so minor stars are not calculated.

AstroSensus does not state the yearly flow, the small limit or a written reading. The free calculator needs no account and uses no AI, and the birth data stays only in the session. Each person saved in an account also has a Zi Wei page.