Overview
Key data
| Item | Detail |
|---|---|
| Period of use | 237 – 442 CE |
| Compiler | Yang Wei |
| Tropical year | 365.2469 days |
| Year head | Jian-yin |
Use and influence
The Jingchu calendar was made by Yang Wei, a secretary of Cao Wei, and promulgated in 237 CE. It carried on the Qianxiang method with improvements and was used until 443 CE — more than two hundred years.
The Northern Wei (398–451) also adopted it, a sign of how widely its methods spread in the Northern and Southern Dynasties.
Values and revisions
Its tropical year of 365.2469 days follows the Qianxiang attempt to bring the fractional part below ¼. It adjusted the lunar and eclipse computations, a link between the calendrical work of Wei-Jin and what followed.
Making a calendar from the ground up required measurement, and later practice always measured against observation.
A note on names
The name comes from the reign-title of Emperor Ming of Wei. Chinese calendars were often named for reign-titles, and the same name does not mean the same calendar: the maker and the date must be checked.
Compiled and arranged by Chujia Kuang.