What is a birthday? Let's give an example.

Date of birth is the calendar date when a person is born; Year, month and day, there are four columns and branches, and each column is eight characters, such as Wushen, Jiazi, Dingmao and Bingwu.

In the almanac, there are basically annual and daily branches, while monthly and hourly branches can be calculated according to the annual and daily branches.

People in ancient China believed that heaven and earth corresponded. The geographical distribution of Kyushu corresponds to the stars, and all beings correspond to the stars. The gold, wood, water, fire and earth that make up the world also correspond to Venus, Jupiter, Mercury, Mars and Saturn in the sky. The sun represents yang and the moon represents yin, so the theory of yin-yang and five elements is combined with astrology.

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Heavenly Stems and Earthly Branches

In ancient China, people took heaven as their work and the earth as their support. There are ten kinds of heavenly stems, including: A, B, C, D, E, Ji, G, Xin, Man and Ghost. There are twelve earthly branches: Zi, Ugly, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai.

Heavenly stems and earthly branches used to record the sun. Ten heavenly stems and twelve earthly branches are combined into sixty units in turn. Odd aerial stems are matched with odd ground branches, and even aerial stems are matched with even ground branches. From Jiazi to Guihai, there are sixty, which is called Sixty Jiazi. In ancient China, people used this method to record the year, month and day, and so on.

In ancient China, people divided a day and a night into twelve hours, but in modern times, one hour is equivalent to two hours, representing five o'clock and six o'clock in the morning in Shi Mao, and so on. By analogy, these four hours, noon, untimely, Shenshi, Youshi, Qishi, Zishi, Ugly and Yin Shi are a whole day and night.

Heavenly stems and earthly branches is not only a tool for ancient people in China to calculate the life span of stars, but also a calendar for calculating time, which is related to the history, culture and daily life of China.

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