What is heaven and earth?

Heavenly stems and earthly branches, abbreviated as Ganzhi, is used to arrange year numbers and dates in the summer calendar. Tiangan is: A, B, C, D, E, Ji, G, Xin, Ren and Gui, also called Tiangan; The earthly branches are: Zi, Ugly, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai, also known as the Twelve Earthly Branches.

At the end of the Warring States period, a historical book, Shi Ben, compiled according to the long-term accumulated data of historians from various countries said: "Rongcheng is the calendar, Dafu is the Jiazi" and "both of them are ministers of the Yellow Emperor. Since the Yellow Emperor, Jiazi has been used to mark one day every 60 days, and Jiazi is a week. " It seems that the main branch was created by Zhuo Da. "Take the five elements of love, occupy the creation of the bucket machine, initiate the name of A and B, and when the child is ugly, take the name of the month as the branch." There is something in the sky, it is used during the day, there is something underground, and the moon is used. Because of the difference between yin and yang, it is a famous branch. "

In Oracle Bone Inscriptions's research, Guo Moruo thinks that people's previous explanations of the official branches are all based on literal speculation, and the "ten branches" are purely the natural occurrence of decimal notation, and most of them were created by Yin people. As for the "Twelve Earthly Branches", it originated in Babylon, and after comparing the twelve points in ancient China with the zodiac in Babylon, it is pointed out that the twelve days and twelve earthly branches in ancient China are all evolved from the twelve zodiac signs in Babylon, Cuba. It can be boldly speculated that the Shang nationality "originally came from the northwest and came with the ephemeris knowledge taught by Babylon, and used it after entering China", or "the Shang nationality originated in the East, and its ephemeris knowledge was imported from the west by merchants or herders".

Some scholars have discovered the unique phenomenon that the characters in the ten-day trunk are used as names from the names of emperors in ancient Xia and Tang Dynasties. In order to refute the theory that stems are foreign, Chen Zungui pointed out in the History of Chinese Astronomy that "stems may have existed in the Xia Dynasty more than 4,000 years ago". In his book The Origin of Astronomy in China, Zheng believes that heavenly stems originated from. "Twelve Branches" evolved from the myth and legend that "there are ten births in the moon" before the Shang Dynasty, and then gradually evolved into "Twelve Branches". Therefore, Zheng concluded: "Twelve branches are probably the creation of Xia people." Du Shiran and others, in their book The History of Science and Technology in China, argued that the Xia Dynasty had a ten-day calendar, and the Shang Dynasty was the basis of the Xia calendar.