What is heavenly stems and earthly branches? What is included?

Heavenly stems and earthly branches is called "dry branch" for short, and works for ten days: A (Ji ǐ), B (yǐ), C (bǐng), D (D ǐ ng), E (W ǐ), Ji (jǐ), g(g ng) and Xin (X). Twelve earthly branches: Zi (zǐ), chou (Chou), Yin (yín), Mao (m ǐ o), Chen (chén), Si (s), Wu (), Wei (wèi) and Shen (shēn). Ugly: cattle; Yin: tiger; Thumb: rabbit; Chen: Dragon; Rudder: snake; Afternoon: horse; No: sheep; Shen: Monkey; Hey: chicken; Hey: dog; H: pigs. )。 Ten branches and twelve branches are matched in turn to form sixty basic units. The ancients used this as the serial number of year, month, day and time, which is called "the discipline of branches and branches". The two cooperate with each other in a fixed order, forming the discipline of cadres and branches. In ancient China, heavenly stems and earthly branches was mainly used to mark dates. In addition, it is also used to mark the month, year and time. As early as 2697 BC, when the Yellow Emperor, the ancestor of China, founded the country, he was ordered to explore the atmosphere of heaven and earth and the five elements (water, fire and earth in Jin Mu), and launched ten days' work on A, B, C, D, E, G, Xin, Ren, Gui, Zi and Ugly. According to the records in Five Elements of Justice, the main branches and branches were created after great efforts. Big scraping "takes the five elements of love and builds it with a bucket machine." Party A and Party B use the name of the day as the basis, and the name of the month as the basis. There is something in the sky that uses the sky, and there is something in the ground that uses the moon. Yin and Yang are different, so there are branches and branches. "In the China calendar, the time for the moon to go around the earth once (29.5306 days) is regarded as January, and the time for the earth to go around the sun once (365.438+09 days) is regarded as a year. In order to make the average number of days in a year consistent with the number of days in the tropical year, a leap month is set up. According to records, in the 6th century BC, China began to coordinate the lunar calendar with the solar calendar by the method of 19. Heavenly stems and earthly branches is a symbol designed by the ancients to facilitate the 60-digit system when building calendars. For ancient China people, the existence of heavenly stems and earthly branches was as simple as Arabic numerals. Later, these symbols were applied to maps, directions and time (time axis and space axis), so these numbers were endowed with more and more meanings. The ancients (Yellow Emperor) observed Wang Shuo's moon and found that the two moons were about 59 days. 1February is generally more than 354 days (similar to the length of a tropical year), so the ancients got the concept of 12 months in a year. In the collocation diary method (ten-day dry), the yin-yang calendar was produced and developed in heavenly stems and earthly branches; It should be more mature in Xia, Shang and Zhou Dynasties.