When did China begin to use heavenly stems and earthly branches to calculate years in ancient times?

According to legend, in the era of the Yellow Emperor, because of the harassment of the God Chiyou, the Yellow Emperor was worried about the people, so he fought Chiyou in the land of Zhuolu, and the bleeding could not be cured. So the Yellow Emperor fasted and bathed, and built altars to worship heaven and earth. The sky falls ten times (i.e. A, B, D, E, G, N, N). Twelve branches (that is, a letter that ugly Mao Yinchen applied for at noon). The emperor made ten pieces of dry circular cloth look like the sky and twelve pieces of square cloth look like the terrain. At first, doing it for the sky, supporting it for the ground, and then it can be cured. As early as 2697 BC, when the Yellow Emperor, the ancestor of China, founded the country, heavenly stems and earthly branches made a scene (Prime Minister of the Yellow Emperor) to explore the qi of heaven and earth and the five elements (water, fire and earth in Jin Mu), and launched A, B, C, D, E, Ji, G, Xin, Ren, Gui, Zi, Ugly, Yin, Mao, Chen and Si. And the founding date of Huang Lai is set as Jiazi Year, Jiazi Month, Jiazi Day and Jiazi Time. This is the origin of heavenly stems and earthly branches's chronology. It is not recorded in Historical Records, but Zhang Shoujie's Justice in Historical Records mentioned that "the Yellow Emperor was inspired by God and was ordered to make Jiazi". "Three Tong Ming Hui" also said, "Yesterday, the Yellow Emperor was divided into sixty jiazi, and posthumous title Huajiazi." As for the order in which Hua Jiazi and Yin Na appeared, The Original Haiziping said that "the person who married Jia Jia started from making a scene, while Yin Na became a guiguzi". Therefore, the calendar in China is called "Huangli" (it is said that it was created by the Yellow Emperor, so it is called "Huangli"). In ancient times, it was calculated and published by Qin Tian Jian, so it was also called the imperial calendar. Its content guides farmers' farming opportunities, so it is also called farmer calendar. Folk commonly known as the general book. However, because the word "book" and "lose" in Tongshu are homophonic, it is also called "Tong Sheng" because of taboo. The solar calendar is based on the lunar calendar in China, and there are many calendars indicating the good or bad of a day. The main contents of the Gregorian calendar are the date table of the twenty-four solar terms, the good and bad luck of each day, the luck of the zodiac and so on.

At first, the sky was only used to record the days, because the number of days in each month was decimal; Earthly branches are used to remember the moon, because the twelve months of a year match the twelve earthly branches. However, not long after, people felt that if only the heavenly stems were used to record the days, three days in a month would still be the same day, so they recorded the dates with a method corresponding to one heavenly stem and one earthly branch respectively. For example, there is a saying in Shangshu Yi Ming, "Only April is full of vitality, and the king is not afraid." Jia Zi, Wang Naitao arched water and was crowned. According to the record of Yu Ji, in the present words, Wang was very uncomfortable at the beginning of April. On Jiazi Day, Wang Cai washed her hair and her eyelids. The servant dressed the king, and Wang Yi sat on the jade table. Later, the method of recording the day was gradually introduced to record the year, month and time. In this way, in the process of practice, a complete system of recording years, months, days and times has gradually formed.