Excuse me, when is the equinox, ugly day, cloudy day, hairy day, etc.

Heavenly stems and earthly branches, referred to as Ganzhi for short, is used to arrange year numbers and dates in the summer calendar.

Calendars use heavenly stems and earthly branches to arrange year numbers and dates. There are ten words in Tiangan, so it is also called "Ten Tiangan". The order of arrangement is: A, B, C, D, E, Ji, G, Xin, Man and Ghost; There are twelve characters in the earthly branch, which are arranged in the following order: Zi, Ugly, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai. Among them, A, C, E, G and N are yang dryness, while B, D, J, Xin and Gui are yin dryness. Zi, Yin, Chen, Wu, Shen and Xu are the Yang branches, while Ugliness, Mao, Si, Wei, You and Hai are the Yin branches.

Dominate a stem with land, arrange them, with the heavenly stem in front, the earthly branch behind, the heavenly stem starting from the nail, the earthly branch starting from the child, the yang stem against the yang branch, and the yin stem against the yin branch (the yang stem against the yin branch and the yin stem against the yang branch), and get a cycle of 60 years. It is called "Sixty Jiazi" or "Flower Jiazi". In the past, China people used to mark the year, month, day and time with a cycle of 60 years.

Heavenly stems and earthly branches's 22 symbols are intricate and orderly, full of harmony and laws. It shows the law of natural operation, the interaction of instant (time) space (orientation) and the result of interaction of yin and yang. China calendar contains the thought of Yin-Yang and Five Elements and the law of natural circulation.

Year: one year for each branch, after 60 branches, start from the beginning and repeat. Starting from Jiazi, it is called Jiazi or Huahua Jiazi 60 years later. It's called the chronology of cadres and branches.

Month: the first month begins in Yin, and the branches of the earth are fixed in each month, and then they are combined with the sky in turn; From the first month to the third month of the first year, February is Ding Maoyue and March is Chen Wu. Jiazi month to Guihai month, Jiazi 60, exactly five years.

Day: Starting from Jiazi Day, arranged in order, the 60th day happens to be a trunk-branch cycle.

Time: Starting from Jiazi, but the branch of punctuality is fixed, twelve hours a day.

The 60th day of a year is roughly a cycle of 2 months; Reuse after a cycle, cycle after cycle, cycle. According to the confirmed documents, the dates of trunks and branches began in February of the third year of the Lu Yingong summer calendar (February 10 BC).

Because julian calendar has an average of 365 days in a year, once every four years, and the AD year is divisible by 4, and there are 366 days in leap years, with an average of 365.25 days in a year, the minimum common multiple of four years 146 1 day and 60 days in Jiazi is 29,220 days, that is, 80 years. That is to say, every 80 years, the date of julian calendar month and day corresponding to the anniversary of the main branch will be repeated. (AD 4 should have been a leap year, but after julian calendar implemented it in 45 BC, it was mistaken that leap days were added every three years, so the Roman emperor Octavian ordered that leap days should be stopped in the first five years, the previous 1 year and the fourth year to correct the mistakes. )

Because the Gregorian calendar has 365 days in a normal year, but once every four years, the year can be divisible by 100 but not by 400, and there are 366 days in a leap year, with an average of 365.2425 days in a year, so the least common multiple of 400 and 60 days of Jiazi is 146097, that is, 292/kloc-0. That is to say, every 80 years, the Gregorian calendar month date corresponding to the branch date will be repeated if there is no AD year divisible by 100 but not by 400. On the whole, assuming that the Gregorian calendar will never change in the future, the Gregorian calendar month date corresponding to the date of trunk and branch will be repeated every 8000 years. 19 12 February 18, which coincides with the first day of the first month of the first lunar month, 18 February 99 12, are all "Jiazi Day".