Overview
Key data
| Item | Detail |
|---|---|
| Completed | 3rd century (Western Jin) |
| Author | Sima Biao |
| Chapters | Treatises 1–3 |
| Core content | The Eastern Han reform debates and the quarter-remainder calendar |
Author and form
The treatises of the Hou Han shu are by Sima Biao and were later printed with Fan Ye’s annals and biographies. Its three parts on pitch and calendar treat of the Eastern Han alone.
The dispute over reform
The treatise records in full the repeated debates: one party for the old methods, one for a new calendar, each testing the other by observation, so that reform was proposed and made again and again.
The matter was settled only in 85 CE with the promulgation of the quarter-remainder calendar. The affair is one of the earliest scholarly disputes on the calendar recorded in detail.
The framing of the calendar
The treatise preserves its procedures and values: a tropical year of 365¼ days, a synodic month of 29.53085 days, seven intercalations in nineteen years.
Its method of testing the calendar by eclipses shows that eclipses were already used as a check.
Value
The calendars of the Eastern Han are known through this treatise; the study of the Later Han calendar and of the Three Kingdoms’ inheritance begins here.
Compiled and arranged by Chujia Kuang.