What is the basis of the chronology of cadres and branches?

The chronology of the dry branch sprouted in the Western Han Dynasty, began with Wang Mang, and prevailed in the late Eastern Han Dynasty. 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. Some people think that China used dry branches to record the years before Emperor Wu of the Han Dynasty. However, this is the Gregorian calendar year of the Prince, which is based on the Gregorian calendar year of the Prince, and the branch represents twelve days (the ecliptic is divided into twelve equal parts). Jupiter 1 1.862 revolves around the sky once a week, so it takes more than 86 years for Tai Sui to pass through one day, which is called "the year of the dry branch is super-Chen". In the Calendar of Zhuan Xu, the first year of Tai Chu (BC 104) of Emperor Wu of the Western Han Dynasty was the prince of Bingzi, and taichu calendar changed it to Ding Chou by surpassing Chen. At the end of the Han Dynasty, Liu Xin changed the first year of Taishu to Bingzi, and the second year of Taishi (the first 95 years) from Yiyou to Bingxu. Scholars who returned to the eastern Han dynasty did not use the super-Chen method. Therefore, from the second year, the chronology of the prince and the chronology of the main branch are the same.

1. The meaning of trunk and branch: trunk and branch are the general names of heavenly stems and earthly branches.

Dry refers to heaven, * * * with 10 symbol:

1 2 3 4 5 6 7 8 9 10

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Refers to the earth, * * * with 12 symbol:

1 2 3 4 5 6 7 8 9 10 1 1 12

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2. The combination of stem and branch is used for dating. That is to say, the ten-day stem and the twelve-day branch are combined to form the stem and branch for dating. According to this arrangement method, 60 branches can be formed after six rounds of arrangement 10 symbols and five rounds of arrangement 12 symbols for ground branches on the same day. If it continues to be discharged, it will return to its original state again and again, which is what the folks call "sixty years of turning to Jiazi".