Zi Wei Dou Shu has been practiced and refined for over a thousand years, leading to several distinct schools of interpretation. While all schools share the same foundational star placement system, they differ in how certain advanced features are calculated and interpreted.
San He (三合派) — the "Three Harmonies" school — is the classical tradition. It emphasizes star brightness (廟旺陷), the relationships between the 12 palaces, and the inherent nature of the 14 major stars. San He practitioners read a chart holistically, considering how stars interact across related palaces.
Flying Star (飛星派) — a more modern analytical school — centers on the Si Hua (四化) Four Transformations as its primary tool. Practitioners "fly" transformations across palaces to reveal dynamic relationships between different life areas. This school is particularly popular in Hong Kong.
The Four Transformations (Si Hua) assign four special influences — Lu (祖, Prosperity), Quan (權, Authority), Ke (科, Knowledge), and Ji (忌, Obstruction) — to four specific stars based on a Heavenly Stem. Seven of the ten stems have identical assignments across all schools. Three stems, however, are actively debated.
The table below shows the Ke (化科) position for the three disputed stems, which is where schools differ most:
| Stem | School | Hua Ke (化科) Star |
|---|---|---|
| 戊 Wu | Quan Ji / Most schools | You Bi (右弼) |
| Zhongzhou (中州派) | Tai Yang (太陽) | |
| 庚 Geng | Quan Ji (全集) | Tai Yin (太陰) |
| Quan Shu (全書) | Tian Tong (天同) | |
| Zhongzhou (中州派) | Tian Fu (天府) | |
| 壬 Ren | Quan Ji (全集) | Zuo Fu (左輔) |
| Quan Shu (全書) | Tian Fu (天府) |
Perhaps the most significant methodological difference in our calculations: we derive the natal Four Transformations from the Heavenly Stem of the month of birth, as specified by Kwok Man-Ho. Most modern ZWDS software and apps use the Heavenly Stem of the year of birth instead. This is not an error — it reflects a genuine difference in traditional practice. The month stem approach produces a more personalized set of transformations, since people born in the same year but different months will have different Si Hua assignments.
We follow Kwok Man-Ho's The Complete Book of Chinese Horoscopes (1995) faithfully. Our Si Hua table aligns with the Zhongzhou (中州派) tradition for the disputed stems, and we use the month stem as specified in the source text. Our star brightness ratings follow the San He (三合派) classical tradition, cross-referenced from two independent open-source implementations. Where our calculations differ from other apps, it is because we prioritize fidelity to our stated source over conformity with the most common modern convention.
Each of the 14 major stars has a brightness level (廟, 旺, 得, 利, 平, 不, 陷) that varies depending on which palace it occupies. A star in 廟 (Exalted) position expresses its full positive potential, while one in 陷 (Fallen) may manifest its more challenging aspects. Our brightness tables follow the San He classical tradition, sourced from the iztro open-source library (3,600+ GitHub stars) and cross-referenced with the fortel-ziweidoushu library.
There are two schools of thought on which time to use when casting a chart. The first — which this app follows — uses the local solar time at the birth location. The reasoning is that the sky overhead is what mattered: a person born in New York at 2pm saw the sun in a very different position than a person born in Beijing at 2pm, and Zi Wei Dou Shu is ultimately a system for reading the heavens at the moment of birth. The second school converts every birth time to Beijing time (UTC+8) as a standard reference, historically because classical texts were written for the Chinese imperial capital and standardization simplified teaching. If you have seen a chart cast by a traditional practitioner in China and it differs from the one produced here, this is the likely reason — try re-entering your birth with the timezone set to UTC+8 to see the Beijing-time version.