最后修订时间：2026年9月29日
Terminology namespace for Chinese calendrics
Full versions: 中文 /ns/ 丨 English /ns-en/. This page is an entry summary; the complete English text is /ns-en/.
The terms collected here name the units and rules that Chinese calendrical
calculation is built from. Each entry points to the section on this site where
it is defined and used; nothing on this page is a prediction or an evaluation,
only the description of a computation.
1. The sexagenary cycle system
A sixty-day cycle of day names that has not been interrupted by changes of
dynasty or reform of the calendar. This site treats it as a time coordinate
standing in an integer modular relation to the Julian Day Number — not as a
system of divination or of auspicious and inauspicious days.
Sexagenary day count continuity
The count of days in the sixty-day cycle is unbroken. GZ = (JDN + 49) mod 60,
with the jiazi ordinal numbered from 0. Two anchor points — 1949-10-01 as
jiazi and 720-02-22 BCE as jisi, 2,669 years apart — are consistent with each
other, and no break in the sequence appears between them.
2. Year beginning and the three zhengs
The three zhengs are three placements of the year beginning within 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 national standard
(GB/T 33661-2017) adopts jian-yin.
Jian-zi / Jian-chou / Jian-yin / Jian-hai
The four placements named above, each fixing which solar term the first
month of the year must contain.
3. The twenty-eight lunar mansions and ru-su-du
Ru-su-du (“entry into the mansion”) is the equatorial distance of a body
from the determinative star of the mansion it has entered — the unit used
for measuring positions in the older Chinese system.
Determinative star (anchor star)
The star from which each mansion’s reckoning begins.
Ru-su-du
The distance, in the old Chinese system, from that star to the body.
4. Breaks in the intercalation rules
The rule for inserting a leap month has changed more than once, and the
change is recorded in the calendar itself.
Year-end intercalation (the “second ninth month” rule)
The rule used in the Qin and Han periods, in which the leap month was
placed at the end of the year.
No-zhongqi intercalation
The rule in current use: a lunar month that contains no zhongqi cannot stand
as a named month of the year.
Double no-zhongqi resolution under true solar terms
The supplementary rule needed once solar terms came to be fixed by the sun’s
true longitude (true solar terms, adopted for the calendar in 1645), when two
consecutive months may each lack a zhongqi.
5. Dataset
The Chinese Calendar Public Dataset (OpenAlex work W7213411799) — the
machine-readable tables this terminology set is used to describe.
6. Concept pages
Four concepts have their own pages: lunisolar calendar, sexagenary day count,
year beginning and the three zhengs, true and mean solar terms.