The Chinese lunar calendar is a traditional calendar inChinaand it is also called Xia Li, Zhong Li, Jiu Li, or Yin Li. It is based on exact astronomical observations of positions of the sun and moon. Thus in essence it is a combined solar/lunar calendar.
In the calendar, one year is divided into 12 months and the months have either 29 or 30 days, always beginning on days of astronomical new moons. So each year has 354 or 355 days. To make the average length of the years equal to a tropical year, an intercalary month is added every two or three years.
As a result, an ordinary year has 12 months while a leap year has 13 months. And an ordinary year has 354, or 355 days, and a leap year has 384 or 385 days.
The calendar is closely related with the development of the astronomy.China is one of the first countries that see the emergence of astronomy, as well as the calendar. As far as 5,000 years ago,Chinahad the lunisolar calendar, which indicated that each year had 366 days.
In the Shang Dynasty (1600-1066BC), officials were appointed to bear the sole task of observing and recording the changes in the heavens. During this period, people used the lunisolar calendar, with an intercalary added to the end of certain years. During the Western Zhou Dynasty (1066-771BC), the astronomer began to measure the shadow cast by the sun and decided upon 24 solar terms to direct the farming.
In the Western Han Dynasty (206BC-23AD), Emperor Wu ordered the establishment of a new calendar --Taichu Calendar, based on the old calendar. And the calendar was used in the next 200 years. In the Eastern Han Dynasty (25-220),Sifen Calendarwas drawn.
Later, Zu Chongzhi worked out theDaming Calendar, taking into consideration the precession of the equinoxes for the first time inChina. After observations and studies, Zu concluded that a year lasted exactly 365.24281481 days which was only 52 seconds different from the modern estimate.
In the Tang Dynasty (618-907), famous monk Yi Xing compiled theDayan Calendar, the most comprehensive and thorough calendar in the Chinese history. The almanac consisted of 7 parts, explaining in details how to calculate the new moon, full moon, 24 solar terms, the movement of the sun and the moon, etc. The calendar had great influences as all the later ones were revised according to it before the introduction of western calendar.
In the Northern Song Dynasty (960-1127), Shen Kuo worked out the 12 Qijie Calendar, discarding the intercalary and this is in line with theGregorian Calendar.
During the Yuan Dynasty (1279-1368), Guo Shoujing compiled theShoushi Calendar. He employed several methods of calculation, including interpolation, spherical trigonometry to solve four main problems in the previous calendars. His calendar had 365.2425 days in a year, which was only 26 seconds different from the time it takes the earth to go around the sun. His achievement was 300 years earli er than the finalization of the modern calendar.
From the Ming Dynasty (1368-1644), Jesuit missionaries brought European astronomy toChina. In the early Qing Dynasty (1644-1911), German missionary Johann Adam Schall von Bell compiled theShixian Calendar. From 1912,Chinabegan to adopt theGregorian Calendar, but the traditional Chinese lunar calendar was still in use. In essence, the lunar calendar wasShixian Calendar.
Chinahas a long history and a lot of traditions. Compared with other countries in the world, it is a typical agricultural country, with a long history of agricultural civilization. And all this, to a great degree, is based on the advanced astronomy and calendar.
The birth of Chinese calendar can be seen as a set of astronomical rules the ancient Chinese summed up for the sake of farming. It took shape after a long time of evolvement. The calendar has two main characteristics:
Firstly, it is closely related with traditional Chinese culture, especially the principles included in theYi Jing. Secondly, it employs a unique computing method -- the Tian Gan (heavenly stems) and Di Zhi (earthly branches) method.