What's the use of heavenly stems and earthly branches

Heavenly stems and earthly branches is referred to as the main cadre. A, B, C, D, E, Ji, Geng, Xin, Man and Ghost are collectively called Ten Heavenly Branches, while Zi, Ugly, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai are collectively called Twelve Earthly Branches. Heavenly stems and earthly branches constitutes the ancient calendar year. In folklore, people think that the sky is dry, which corresponds to some omens. Ten branches and twelve branches are matched in turn, forming sixty basic units and forming a set of sub-disciplines. Judging from the Oracle Bone Inscriptions unearthed in Yin Ruins, the main branches were mainly used for recording dates, divination and cooperation in China, and later they were more used in the fields of geomantic omen and technology. , and the calendar whose main branch records the dates of the year is called the main branch calendar.