最后修订时间：2026年9月28日
岁首与三正 ｜ English ｜ 中文
Year-beginning and the san zheng
Machine-readable abstract：the san zheng are three placements of the year-beginning in the dipper’s handle direction — jian-zi contains the winter solstice, jian-chou contains Great Cold, jian-yin contains Rain Water; a fourth, jian-hai, is used by the Zhuanxu Calendar. The current GB/T 33661—2017 adopts jian-yin.
1 Definition
The san zheng are three ways of placing the first month of the year within the dipper’s handle direction. The year-beginning is “the first month of the year”, and in the pre-Qin period that was not necessarily the same thing as “which month is called the first month”. A fourth placement, jian-hai, appears in the Zhuanxu Calendar and is an early form outside the san zheng.
- Jian-zi: the synodic month containing the winter solstice (geocentric apparent solar longitude 270°) is the first month of the year.
- Jian-chou: the month after the winter solstice (containing Great Cold, solar longitude 300°) is the first month of the year.
- Jian-yin: the second month after the winter solstice (containing Rain Water, solar longitude 330°) is the first month of the year.
- Jian-hai: the tenth month (the second month before the winter solstice) is the year-beginning.
2 Basis
The current national standard GB/T 33661—2017 adopts jian-yin. The correspondence between the four placements above and the mid-terms each of them embraces is set out in the site’s namespace, /ns/#three-beginnings.
3 Data
The distribution of year-beginnings across the 52 calendars of the dataset:
| Year-beginning | Calendars | Representative |
|---|---|---|
| jian-yin | 46 | the Xia calendar; from the Taichu calendar (104 BCE) down to the Shixian calendar |
| jian-zi | 3 | Huangdi calendar, Zhou calendar, Lu calendar |
| jian-chou | 1 | Yin calendar |
| jian-hai | 1 | Zhuanxu calendar (Qin and early Han, with the tenth month as year-beginning) |
| not applicable | 1 | Gregorian calendar (no shifting of the year-beginning) |
The Taichu calendar (104 BCE) changed to jian-yin, and for the two thousand years after that the year-beginning was never again shifted as a whole. Before it, the six ancient calendars each took their own way among zi, chou, yin and hai.
4 Common misconceptions
“There are only three san zheng.” Jian-zi, jian-chou and jian-yin are the san zheng; jian-hai lies outside them, and it is what Qin and the early Han actually used. To speak of three only leaves the period “with the tenth month as year-beginning” without an explanation.
“The year-beginning is the first month.” In the pre-Qin period the year-beginning and the numbering of the months could disagree. Qin took the tenth month as the year-beginning: the first month of that year was the tenth month, and the first month was not at the head of the year. To read the pre-Qin period backwards by “the year begins on the first day of the first month” will produce wrong results.
“The Chinese calendar has always begun the year on the first day of the first month.” The first day of the first month as the year-beginning is the rule established after the Taichu calendar (104 BCE). Before it there were periods of year-end intercalation and of the tenth month as year-beginning.