Overview
Key data
| Item | Detail |
|---|---|
| Author | Yuan Tong (early Ming) |
| Completed | Early Ming |
| Volumes | Four |
| Core content | Tables and computational procedures of the Datong calendar |
Book and calendar
Ming used the Datong calendar, whose methods in fact continue the Yuan Shoushi calendar with its figures unchanged.
The Datong Lifa Tonggui is its computational manual, setting out the methods step by step in a sequence that can be followed.
⚠ Note that the Datong calendar and Zu Chongzhi’s Daming calendar are close in name but wholly different; the two must not be conflated.
Contents and form
The book is arranged in computational order: the tables first, then the steps of each calculation,
covering ecliptic and lunar motion, the sun’s and moon’s positions, and eclipses, each with its procedure.
Its figures agree largely with the Shoushi calendar, so that the book may be read as the practical form of the Shoushi methods under the Ming.
Value
For how the Ming calendar was actually used, this book is the direct source.
Its tables and procedures are also material for the study of the actual computation of ancient calendars.
Compiled and arranged by Chujia Kuang.