There were four main chronologies in ancient China.

There are four main types of ancient chronologies in China:

In ancient China, there were four common chronologies, namely, the chronology of the main branches, the chronology of the year number, the chronology of the year number and the chronology of the main branches.

Tree trunk and branch chronology

Chronology of cadres and branches, full name "Chronology of cadres and branches". Ten-day trunk and twelve-day branches are combined in pairs, and one trunk and branch combination is named for one year, and one group is postponed every year and rotated repeatedly.

Ten days of work are: a, b, c, d, noon, self, g, Xin, people and ghosts. The twelve earthly branches are: Zi, Ugly, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai.

The chronology of cadres and branches is the most commonly used ancient chronology, and its shadow can still be seen today. For example, this year is 2022, which is the year of Renyin in China.

Chronology of year number

Beginning with Emperor Wu of the Han Dynasty, emperors began to name titles, and the chronology of ancient titles in China followed. The reigning emperor can choose a word to name a year, which is called "the first year of xx", the next year is called "the second year of xx", and so on. Such as "the first year of Jianyuan" and "the second year of Jianyuan" ...

There are several special cases of year number: one is a multi-word year number with more than two words; The second is to change the number without changing the number; Third, every monarch had only one title in the Ming and Qing Dynasties.

The method of year number and age has long been abandoned today, but it is an indispensable part of historical research.

Chronology of princes

This kind of chronology is not common, only in the Spring and Autumn Period and the Warring States Period, and it is rare after the Spring and Autumn Period and the Warring States Period. The method of chronology of princes is to express dates by titles and numbers of princes of vassal states, such as "xx year of Qi Huangong".

Chronology and year of branches and branches

This kind of chronology is complicated to use, so it is not common. As the name implies, the year is calculated by the year number taken by the emperor and the corresponding heavenly stems and earthly branches.

There is a typical "Xi Chun Shen Bing" in Jiang Kui's poem "Yang Zhou Man Huai Zuo Du Ming", which is a combination of Xi Chun and Shen Bing.