Overview
Key data
| Item | Detail |
|---|---|
| Completed | c. 82 CE |
| Author | Ban Gu |
| Chapter | 21, parts 1–2 |
| Core content | The Santong calendar’s methods and the theory of pitch |
Pitch pipes and calendar joined
The Han shu joins music and the calendar in one treatise, the “lü-li zhi.” The ancients took pitch pipes to await the seasons and pitch numbers to match calendrical ones, holding the two to be one in origin — hence the name.
The practice of joining the calendar and astronomy in one treatise began with the Shiji and took its fixed form here; thereafter the histories kept to it.
The calendar it preserves
Ban Gu based the treatise on Liu Xin’s Santong calendar, gathering the methods and exposition from the Taichu reform on. It is the only complete source for the Taichu and Santong calendars alike.
Its eighty-one-part method, grand epoch and arrangement of new moons and intercalations are found nowhere else.
Other contents
The treatise also treats weights and measures, the lengths of pitch pipes and the method of awaiting the seasons, binding pitch, measure and calendar into one system — a sign of Han learning’s sense of wholeness.
It also preserves pre-Qin calendrical debates, essential for tracing the calendar before the Han.
A quotation
On the Taichu reform it says:
Compiled and arranged by Chujia Kuang.