Two oracle bones from the Shang Dynasty in China (c. 1800 - 1200 BCE)Evidence from the Shang oracle bone inscriptions shows that at least by the 14th century BC the Shang Chinese had established the solar year at 365¼ days and lunation at 29½ days. In the calendar that the Shang used, the seasons of the year and the phases of the Moon were all supposedly accounted for.Source: http://www.webexhibits.org
Saturday, January 21, 2012
THE CHINESE CALENDER
Chinese New Year is the main holiday of the year for more than one quarter of the world’s population. Although the People’s Republic of China uses the Gregorian calendar for civil purposes, a special Chinese calendar is used for determining festivals. Various Chinese communities around the world also use this calendar.
The beginnings of the Chinese calendar can be traced back to the 14th century B.C.E. Legend has it that the Emperor Huangdi invented the calendar in 2637 B.C.E.
The Chinese calendar is based on exact astronomical observations of the longitude of the sun and the phases of the moon. This means that principles of modern science have had an impact on the Chinese calendar.
What Does the Chinese Year Look Like?
The Chinese calendar - like the Hebrew - is a combined solar/lunar calendar in that it strives to have its years coincide with the tropical year and its months coincide with the synodic months. It is not surprising that a few similarities exist between the Chinese and the Hebrew calendar:
An ordinary year has 12 months, a leap year has 13 months.
An ordinary year has 353, 354, or 355 days, a leap year has 383, 384, or 385 days.
When determining what a Chinese year looks like, one must make a number of astronomical calculations:
First, determine the dates for the new moons. Here, a new moon is the completely "black" moon (that is, when the moon is in conjunction with the sun), not the first visible crescent used in the Islamic and Hebrew calendars. The date of a new moon is the first day of a new month.
Second, determine the dates when the sun’s longitude is a multiple of 30 degrees. (The sun’s longitude is 0 at Vernal Equinox, 90 at Summer Solstice, 180 at Autumnal Equinox, and 270 at Winter Solstice.) These dates are called the Principal Terms and are used to determine the number of each month:
Principal Term 1 occurs when the sun’s longitude is 330 degrees.
Principal Term 2 occurs when the sun’s longitude is 0 degrees.
Principal Term 3 occurs when the sun’s longitude is 30 degrees. (etc.)
Principal Term 11 occurs when the sun’s longitude is 270 degrees.
Principal Term 12 occurs when the sun’s longitude is 300 degrees.
Each month carries the number of the Principal Term that occurs in that month.
In rare cases, a month may contain two Principal Terms; in this case the months numbers may have to be shifted. Principal Term 11 (Winter Solstice) must always fall in the 11th month.
All the astronomical calculations are carried out for the meridian 120 degrees east of Greenwich. This roughly corresponds to the east coast of China.
Some variations in these rules are seen in various Chinese communities.
What Years Are Leap Years?
Leap years have 13 months. To determine if a year is a leap year, calculate the number of new moons between the 11th month in one year (i.e., the month containing the Winter Solstice) and the 11th month in the following year. If there are 13 new moons from the start of the 11th month in the first year to the start of the 11th month in the second year, a leap month must be inserted.
In leap years, at least one month does not contain a Principal Term. The first such month is the leap month. It carries the same number as the previous month, with the additional note that it is the leap month.
How Does One Count Years?
Unlike most other calendars, the Chinese calendar does not count years in an infinite sequence. Instead years have names that are repeated every 60 years.
(Historically, years used to be counted since the accession of an emperor, but this was abolished after the 1911 revolution.)
Within each 60-year cycle, each year is assigned name consisting of two components:
The first component is a Celestial Stemm. These words have no English equivalent:
1 jia 6 ji
2 yi 7 geng
3 bing 8 xin
4 ding 9 ren
5 wu 10 gui
The second component is a Terrestrial Branch. The names of the corresponding animals in the zodiac cycle of 12 animals are given in parentheses.
1 zi (rat) 7 wu (horse)
2 chou (ox) 8 wei (sheep)
3 yin (tiger) 9 shen (monkey)
4 mao (hare, rabbit) 10 you (rooster)
5 chen (dragon) 11 xu (dog)
6 si (snake) 12 hai (pig)
Each of the two components is used sequentially. Thus, the 1st year of the 60-year cycle becomes jia-zi, the 2nd year is yi-chou, the 3rd year is bing-yin, etc. When we reach the end of a component, we start from the beginning: The 10th year is gui-you, the 11th year is jia-xu (restarting the Celestial Stem), the 12th year is yi-hai, and the 13th year is bing-zi (restarting the Terrestrial Branch). Finally, the 60th year becomes gui-hai.
This way of naming years within a 60-year cycle goes back approximately 2000 years. A similar naming of days and months has fallen into disuse, but the date name is still listed in calendars.
It is customary to number the 60-year cycles since 2637 B.C.E., when the calendar was supposedly invented. In that year the first 60-year cycle started.
What Is the Current Year in the Chinese Calendar?
The current 60-year cycle started on 2 Feb 1984. That date bears the name bing-yin in the 60-day cycle, and the first month of that first year bears the name gui-chou in the 60-month cycle.
This means that the year wu-yin, the 15th year in the 78th cycle, started on 28 Jan 1998. The 20th year in the 78th cycle, started on 1 Feb 2003.
The following are dates for Chinese/Lunar New Year’s day:
Chinese year Zodiac animal Gregorian calendar
4693 Boar January 31, 1995
4694 Rat February 19, 1996
4695 Ox February 7, 1997
4696 Tiger January 28, 1998
4697 Hare/Rabbit February 16, 1999
4698 Dragon February 5, 2000
4699 Snake January 24, 2001
4700 Horse February 12, 2002
4701 Ram/Sheep February 1, 2003
4702 Monkey January 22, 2004
4703 Rooster February 9, 2005
4704 Dog January 29, 2006
4705 Boar February 18, 2007
4706 Rat February 7, 2008
4707 Ox January 26, 2009
4708 Tiger February 10, 2010
4709 Hare/Rabbit February 3, 2011
4710 Dragon January 23, 2012
4711 Snake February 10, 2013
4712 Horse January 31, 2014
4713 Ram/Sheep February 19, 2015
4714 Monkey February 9, 2016
4715 Rooster January 28, 2017
4716 Dog February 16, 2018
4717 Boar February 5, 2019
4718 Rat January 25, 2020
What about the year 2033?
In the early 1990s, Chinese astronomers discovered that there was an error in the Chinese calendar for 2033. The traditional calendar claimed that the leap month would follow the 7th month, while in fact it comes after the 11th month. It is very unusual that the 11th month has a leap month, in fact it hasn’t happened since the calendar reform in 1645 (before 1645, all months had the same probability for having a leap month). But many Chinese astronomers still claim that there will never be a leap month after the 12th and 1st month. In addition, there will be a leap month after the 1st month in 2262 (in fact, it should have happened in 1651, but they got the calculations wrong!) and there will be a leap month after the 12th month in 3358. Since the Chinese calendar is an astronomical calendar, predictions require delicate astronomical calculations, so my computations for 3358 should probably be taken with a grain of salt.
When did the calendar really start?
If the Chinese calendar started in 2637 B.C.E., why is the current year 60 years too late? (e.g., in 1999, the current year was 4697? and not 4637)?
The Chinese calendar does not use a continuous year count! They used a 60 year cycle and a system of regional years (starting with each emperor). Before the 1911 revolution, Sun Yat-sen wanted to establish a republican alternative to the imperial reign cycles. According to Chinese tradition, the first year of the Yellow Emperor was 2698 B.C.E., so he introduced a counting system based on this. Under this system, 2000 is year 4698. An alternative system is to start with the first historical record of the 60-day cycle from March 8, 2637 B.C.E. Based on this system, 2000 is year 4637.
What was the Early Chinese calendar?
In China, the calendar was a sacred document, sponsored and promulgated by the reigning monarch. For more than two millennia, a Bureau of Astronomy made astronomical observations, calculated astronomical events such as eclipses, prepared astrological predictions, and maintained the calendar. After all, a successful calendar not only served practical needs, but also confirmed the consonance between Heaven and the imperial court.
Analysis of surviving astronomical records inscribed on oracle bones reveals a Chinese lunisolar calendar, with intercalation of lunar months, dating back to the Shang dynasty of the fourteenth century B.C.E. Various intercalation schemes were developed for the early calendars, including the nineteen-year and 76-year lunar phase cycles that came to be known in the West as the Metonic cycle and Callipic cycle.
From the earliest records, the beginning of the year occurred at a New Moon near the winter solstice. The choice of month for beginning the civil year varied with time and place, however. In the late second century B.C.E., a calendar reform established the practice, which continues today, of requiring the winter solstice to occur in month 11. This reform also introduced the intercalation system in which dates of New Moons are compared with the 24 solar terms. However, calculations were based on the mean motions resulting from the cyclic relationships. Inequalities in the Moon’s motions were incorporated as early as the seventh century C.E., but the Sun’s mean longitude was used for calculating the solar terms until 1644.
Years were counted from a succession of eras established by reigning emperors. Although the accession of an emperor would mark a new era, an emperor might also declare a new era at various times within his reign. The introduction of a new era was an attempt to reestablish a broken connection between Heaven and Earth, as personified by the emperor. The break might be revealed by the death of an emperor, the occurrence of a natural disaster, or the failure of astronomers to predict a celestial event such as an eclipse. In the latter case, a new era might mark the introduction of new astronomical or calendrical models.
Sexagenary cycles were used to count years, months, days, and fractions of a day using the set of Celestial Stems and Terrestrial Branches. Use of the sixty-day cycle is seen in the earliest astronomical records. By contrast the sixty-year cycle was introduced in the first century C.E. or possibly a century earlier. Although the day count has fallen into disuse in everyday life, it is still tabulated in calendars. The initial year (jia-zi) of the current year cycle began on 1984 February 2, which is the third day (bing-yin) of the day cycle.