Ten heavenly stems and twelve earthly branches are matched in turn, forming a total of 60 years of stem and branch years, with 60 years as a cycle. A cycle of annals of cadres and branches is "Jia Zi" in the first year, "Ugly B" in the second year, and so on, with a cycle of 60 years; After a cycle, it will be reused again and again.
Extended data:
The trunk calendar is mainly composed of four parts: trunk calendar year, trunk calendar month, trunk calendar day and trunk duration. The trunk calendar and the lunar calendar are two different calendars. Ganzhi Calendar, also known as Jiazi Calendar, is a unique solar calendar in China and the crystallization of the wisdom of China people. As a calendar, it has been implemented for thousands of years. It was created with full reference to the relationship between the ecliptic and the earth, with beginning of spring as New Year's Day and the tropic of Capricorn as a year.
In the contemporary lunar calendar, it is a general symbol to borrow and support the calendar year, starting from the first day of the first month; The book "Ancient Calendar of China", a national key book publishing planning project in the 11th Five-Year Plan, points out that the calendar year of cadres and branches began in beginning of spring. Heavenly stems and earthly branches's 22 symbols are intricate and orderly, full of harmony and laws.
Baidu Encyclopedia-heavenly stems and earthly branches