Chinese Customs & Festivals

Paper Cut

Chinese Lunar Calendar

In much of the countryside, Spring Festival is still the term used for New Year's Day. The year of 2008 marked the start of the "Year of the Rat" according to the Chinese lunar calendar.

Why rat? The ancient Chinese called each succeeding year by the name of an animal. They had 12 such names and after they had run through the list they start over again.

By the Shang Dynasty, from 16th to 11th century BC, unearthed oracle bones show that the Chinese had devised a complicated method of counting time - first days, then hours, months and years - called the ganzhi meaning stems and branches. There are a total of 10 heavenly stems and 12 earthly branches. The stems are named jia, yi, bing, ding, wu, ji, geng, xin, ren and gui, but expressed in written Chinese characters. Think of them as the 12 letters of the alphabet (A through L). Combining them allows you to count to 60 in this way: Jiazi (1-A); yichou (2-B); bingyin (3-C), etc. When you reach gui (10), you start over with jia (1), but you still have two more branches to go before repeating them; so 11 is jiaxu (1-K), 13 is bingzi (3-A), 35 is wuxu (5-K) and 60 is guihai (10-L).

In time, various animals had become identified with the earthly branches. And various superstitions, like checking to see if proposed marriage partners had been born under compatible signs, came to be as well. For instance, a dragon and a tiger should not marry, nor should a cock and a tiger. If that sounds like Western astrology, there is something to it. Even more remarkable is the coincidence between the ancient Greek's circular representation of the zodiac with its 12 pictorial symbols around the rim and the ancient Chinese’s drawing of the earthly branches, also round and circled by 12 animals. By 1,400 BC, the Shang Dynasty had established that the year, a complete cycle of the seasons, is 365 1/4 days long, that the time between two new moons is 29 days, but that a lunar year (12 "moons" or months) is only 354 days long. To compensate for this discrepancy, they began to repeat a month whenever the officials in charge decided they were a month out of sync. Thus, there might be two "seventh month" in one year.

But this practice was soon abandoned and a 13th month was added periodically at the end of the year. In the early years of the Spring and Autumn Period, from 770 to 476 BC, the Chinese had figured out the length of the year so accurately that they were adding seven extra months to every 19 years. By 475 BC, this calculation had been honed to 144 extra months for every 391 years. In the meantime, however, the first system – the one repeating various months – had again gained favour but with an addition: a set method of determining which months should be repeated.

Between 300-200 BC, a new procedure of dividing the year into weather cycles was adopted. Called the 24 Seasonal Points, this new system was designed to help farm work. With colourful names like "Excited Insects", "Clear and Bright", "Grain Rains", "a Little Cold", the points were 15 or 16 days apart. Usually, each solar month would contain two points. This was not always so with the lunar months because two such periods would extend over an average of 30.4 days and the lunar month is only 29 1/2 days. Months containing only one point would be repeated.

1 2 3 4 5 6 7 8 9 10
A B C D E F G H I J
1 2 3 4 5 6 7 8 9 10
K L A B C D E F G H
1 2 3 4 5 6 7 8 9 10
I J K L A B C D E F
1 2 3 4 5 6 7 8 9 10
G H I J K L A B C D
1 2 3 4 5 6 7 8 9 10
E F G H I J K L A B
1 2 3 4 5 6 7 8 9 10
C D E F G H I J K L

How the ganzhi cycle of 60 works out using numbers and letters in place of the characters
or words for the 10 heavenly stems (top row) and the 12 earthly branches (bottem row).

Revised June 2, 2011