When does the calendar year in heavenly stems and earthly branches begin?

Since ancient times, beginning of spring has been regarded as the beginning of a year.

Heavenly stem algorithm: the number of digits corresponding to heavenly stem is obtained by subtracting 3 from the number of years in A.D. and dividing it by 10 (without considering quotient), while the number of digits corresponding to earthly branch algorithm: the number of digits corresponding to earthly branch is obtained by subtracting 3 from the number of years in A.D. and dividing it by 12 (without considering quotient).

The corresponding numbers of Rhizoma Drynariae are: A, B, C, D, E, E, G, Xin, Ren and Gui.

Corresponding digits of earthly branches: Zi, Ugly, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai.

Extended data:

Origin:

The chronology of cadres and branches is a chronology method used since ancient times in the history of China. Stem and branch are the floorboards of heavenly stems and earthly branches. At the beginning of the Eastern Han Dynasty, Emperor Guangwu Liu Xiu stipulated that people should use the year of dry support. In the second year of Emperor Yuanhe of the Han and Yuan Dynasties (AD 85), the court ordered the nationwide implementation of the chronicle of cadres. Since then, the chronology of the main branches has been fixed and has continued to this day without confusion.

Zhang Peiyu, a contemporary astronomer, also pointed out in the Ancient Calendar of China: For two thousand years, the chronology of China's trunk and branch and the chronological order of the calendar have cooperated with each other and formed their own system. It takes beginning of spring as the beginning of the year and festivals as the beginning of the month.

The solar calendar of the National Time Service Center of Chinese Academy of Sciences has a complete calendar, with the solar terms in beginning of spring as the dividing line of the year.

Baidu Encyclopedia-heavenly stems and earthly branches

Baidu encyclopedia-yearbook of cadres and branches