A Textual Study of the Eight Characters of Daoist Master Wu Chongxu
2019-11-04. Illustrations omitted.
[Genealogy]
1: Jiaxu · Bingyin · Gengchen · Jiashen
[Immortality-Cultivation Song of Master Wu]
2: Jiaxu · Yichou · Dingchou · Bingwu
3: Guiyou · Yichou · Dingchou · Bingwu
The winter-solstice term-change time of 1573 — during the Wanli era, the use of the vernal equinox as the zero-degree node had not yet begun.
So it should be based on data measured from the winter-solstice solar shadow. The previous shortest winter-solstice shadow was at 10:03:48 on December 17, 1573. By January 23, 1574 — a Gengchen day, the first day of the first lunar month, New Year's Day — it is confirmed that Lichun (Start of Spring) had not yet arrived; adding the precession calculation, the term change falls precisely on January 26.
In the Ming dynasty, the first day of the first lunar month was the Zhengdan Festival. The Immortality-Cultivation Song of Master Wu explicitly states that he was born at noon on Zhengdan of the second year. If Master Wu's account is correct, then the records in his family's genealogy must be wrong.
But genealogies are not deliberately written with errors. If the mistake occurred during a revision, that makes it all the more puzzling: the Wu family produced such a peerless figure — how could they not have carefully inquired and recorded it?
If the genealogy is authentic, only two possibilities remain. The first is that the Immortality-Cultivation Song of Master Wu was in fact a biography written by someone else on his behalf, since the earliest version one can find dates only to the Kangxi era. The second is that Master Wu did not wish people to know his true Eight Characters, hence the saying.