Geographical problems: the method of ancient chronology in China?

The most basic chronology in ancient China used the "trunk and branch" chronology.

The chronological method of "Ganzhi" is based on the ten days of "A, B, C, D, E, Ji, G, Xin, Ren and Gui" and the twelve days of "Zi, Ugly, Yin, Mao, Chen, Ji, Wu, Wei, Shen, You, Xu and Hai" 1. When all the branches are matched, it is called Dajiazi, who is 60 years old. ?

And use the year of the emperor. For example, Kangxi 30 years, Zhenguan 14 years, …

Attachment: heavenly stems and earthly branches Matching Table