Zi Wei Dou Shu
Purple Star astrology, Chinese, attributed to Chen Tuan
Zi Wei Dou Shu, 'the Purple Star of the Northern Dipper,' is traditionally attributed to the Song-era sage Chen Tuan and splits into two lineages, San He and Si Hua. An early Daoist text of 1607 sharing the name uses none of the fourteen major stars of the modern art (though it shares some minor star names), so Chinese scholarship treats them as different arts that happen to share a title — the real textual history is uncertain.
What it measures
A twelve-palace chart built from the Chinese lunar calendar. The seat of the star Zi Wei is found from the lunar day and the Bureau, and it then fixes all thirteen other major stars deterministically — five of its own group at set offsets from it, and eight of the Tian Fu group at set offsets from Tian Fu, which sits at Zi Wei's reflection across the Yin–Shen axis.
Still open
Traditional star brightness levels vary between schools, so we omit them rather than pick one silently.
Sources
- Chen Tuan (attrib.), Zi Wei Dou Shu