Although the revolutionary government of China announced the abolition of the traditional Chinese calendar (Huangli) and using the Gregorian calendar as standard calendar since 1/1/1912, the traditional Chinese calendar is still in use in various Chinese communities. Popular Chinese almanacs are published annually and provide information about Chinese lunisolar calendar and Ganzhi calendar of the year. After the end of the imperial era in 1911, people generally call traditional Chinese calendar Yinli (In opposite to Yangli mentioned later in this paragraph), Jiuli (Old-style calendar), Nongli (Farmer calendar), Xiali (Xia-dynasty-style calendar), or Minli (people's calendar), and call the Gregorian calendar Yangli (In opposite to Yinli mentioned above), Xili (Western Calendar), Gongli (reckoning by Christian era), or Xinli (New-style calendar).
In 1953, there were two versions of the traditional Chinese calendar in Mainland China and in Hong Kong. According to the version which was based on the Wannianli of Xuantong imperial era, the 6th lunar month was a "small month" (29 days) and the 7th lunar month was a "big month" (30 days). However, the other version which was based on the calculations of Purple Mountain Observatory was just the opposite - it stated that the 6th month was a "big month" and the 7th month was a "small month". The same difference occurred in 1978 and 1989. Therefore, if you take Wannianli as your reference to traditional Chinese calendar or Jieqi, be aware that there may be some differences among Wannianlis from different sources. One more piece of information, Wannianli is a calendar of 100 or, in some editions, 200 years.
Traditional Chinese calendar is a lunisolar calendar, and is based on the exact longitude of the sun and the phases of the moon. In addition, years, months, dates and hours are named in Ganzhi (60 combinations of Clestial/Heavenly Stem and Terrestrial/Earthly Branch) sequentially for counting and keeping track of time passage, this is known as Ganzhi Calendar. Please read another page on Calendrical Jiazi for details of Ganzhi Calendar.
Here are rules for Chinese calendar.
1. Calculations are based on the meridian at longitude 120° East.
2. Days are measured from midnight to midnight.
3. Determine the time of 12 Jie and 12 Zhong. 12 Jie coincide with points 30° apart on the ecliptic (the path along which the sun seems to move). These 12 points are used for determining twelve solar months. Lichun (at the time the sun's longitude is 315°) is the beginning of a year and the beginning of the first month. And the Terrestrial/Earthly Branch of the first month is Yin. The mid-points between two Jie are called Zhong and known as Zhongqi. These 12 Zhong are used for determining whether to insert an intercalary lunar month or not. 12 Jie and 12 Zhong are generally called twenty-four Jieqi or twenty-four Qi.
Term Sun's Longitude Jie 1 Li Chun Beginning of Spring 315 Qi 1 Yu Shui Rain Water 330 Jie 2 Jing Zhe Waking of Insects 345 Qi 2 Chun Fen Spring Equinox 0 Jie 3 Qing Ming Pure Brightness 15 Qi 3 Gu Yu Grain Rain 30 Jie 4 Li Xia Beginning of Summer 45 Qi 4 Xiao Man Grain Full 60 Jie 5 Mang Zhong Grain in Ear 75 Qi 5 Xia Zhi Summer Solstice 90 Jie 6 Xiao Shu Slight Heat 105 Qi 6 Da Shu Great Heat 120 Jie 7 Li Qiu Beginning of Autumn 135 Qi 7 Chu Shu Limit of Heat 150 Jie 8 Bai Lu White Dew 165 Qi 8 Qiu Fen Autumnal Equinox 180 Jie 9 Han Lu Cold Dew 195 Qi 9 Shuang Jiang Descent of Frost 210 Jie 10 Li Dong Beginning of Winter 225 Qi 10 Xiao Xue Slight Snow 240 Jie 11 Da Xue Great Snow 255 Qi 11 Dong Zhi Winter Solstice 270 Jie 12 Xiao Han Slight Cold 285 Qi 12 Da Han Great Cold 300
4. The day of the new moon (the Dark of the Moon or the Black Moon) is the first day of a lunar month.
5. In the Chinese lunar calendar year, the eleventh month always has the December solstice in it.
6. If there are 14 lunar months between two December solstices (includes two months having winter solstice), the first month that does not has Zhong Qi is an intercalary month, Run Yue (pinyin pronunciation ). This intercalary month carries the same number as the previous month.
This animated picture shows the simulated astronomical phenomenon of 1984.
(This calculation is based on the meridian at longitude 120° East.)
Gan Zhi Calendar
(Stem and Branch Calendar)
Year Month Day