乾元历
Northern Song · Wu Zhaosu
Overview
Promulgated in 980 CE under Wu Zhaosu and used for twenty years.
Key data
| Item | Detail |
|---|---|
| Period of use | 981 – 1000 CE |
| Compiler | Wu Zhaosu |
| Year head | Jian-yin |
Development
The Qianyuan calendar was made by Wu Zhaosu, promulgated in 980 CE, replacing the Yingtian and used until 1000.
It followed the old methods with little innovation. The tension between inertia and reform among Northern Song calendrists shows in this succession of changes.
The rhythm of reform
From Jianlong to Jingkang the Northern Song changed its calendar more than ten times — Yingtian, Qianyuan, Yitian, Chongtian, Mingtian, Fengyuan, Guantian, Zhantian, Jiyuan and others — a change about every twenty years, a sign of diligent measurement and debate.
Compiled and arranged by Chujia Kuang.