How long does it take to cycle once in a thousand years?
Heavenly stems and earthly branches chronology is a 60-year cycle. Heavenly stems and earthly branches chronology is a 60-year cycle. Ten branches and twelve branches are matched in turn to form 60 basic units, which cooperate with each other in a fixed order, such as Jiazi, Yechou, Bingyin, Dingmao, Chen Wu, Keith, Wu Geng, Xinwei, Renshen, Gui You, JOE, Yihai, Bingzi and Dingchou.