What are the twelve branches of heaven and earth?
The "twelve earthly branches" are: Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai.
Heavenly stems and earthly branches corresponds, A corresponds to sub, B corresponds to ugliness, and decyl corresponds to unitary. However, the heavenly stems are two bits less than the earthly branches, so the heavenly stems cycle first, with A corresponding to 100, B corresponding to 100, and then the earthly branches cycle, and C corresponding to the sub. It has been 60 years since Jiazi met again, which means that Jiazi is often said to be 60 years.
Extended data
The source of "heavenly stems and earthly branches":
Heavenly stems and earthly branches originated from the observation of astronomical phenomena in ancient China. China has had 10-day stems and 12-day branches since ancient times, referred to as "stems and branches", which means stems and branches of trees. Heavenly stems and earthly branches constitutes the ancient calendar.
Ten branches and twelve branches are matched in turn to form sixty basic units, which cooperate with each other in a fixed order to form the epoch method of branches and branches. Judging from the Oracle Bone Inscriptions unearthed in Yin Ruins, in ancient China, the trunk and branch were mainly used to record the days, as well as the months, years and hours.
Du Shiran and others argued in the book History of Science and Technology in China that there was a ten-day dry calendar in Xia Dynasty, and the Shang Dynasty further used the dry calendar in Xia Dynasty, thus combining the ten-day dry calendar with the twelve earthly branches to form a sixty-week calendar.
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