In the ancient imperial era, there was the embryonic form of Ganzhi calendar and Nian. "Ganzhi" was called "Lao" in ancient times. According to the records of Pangu Wang Biao and Three Meetings, "the name of the first emperor is named after the name of the branch, and the age is determined." Ten days of work: Fu Feng, You Meng, Ruan Zhao, Qiang Qiang, Zhu Yong, Tu Wei, Zhang Shang, Shi Guang, Xuan _, Zhao Yang; Twelve places support: Pat Teague, Shan Yu, Xu Zhi, Great Wilderness, Dun _, Qi Xie, _ Beach, Zuo Meng, Mao Yan, Dayuanxian, Dilemma, and Red Powder. In Erya Shi Tian, it is said that "old yin, child yin, ugly yin, gross yin, old yin, fourth yin, afternoon yin, Wei yin, Shen yin, unitary yin, Xu yin and Hai yin" are the months. Similarly, the order of the twelve branches also contains the development and change process of things.