1, and Party A, Party B, Party C, Party D, Party E, Party B, Party G, Party A, Party B, Party B, Party B, Party B, Party B, Party B, Party B and Party B are called "ten-day work";

2. Zi, Ugliness, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai are called "Twelve Branches".

Any word in the heavenly stems can be combined with any word in the earthly branches. * * There are 10 groups, each group has 12 and * * has 120.

However, the chronology of heavenly stems and earthly branches must be based on the fact that the heavenly stems are behind the earthly branches, excluding the combination of earthly branches after the heavenly stems, so only half of the 65,438+020 combinations meet the requirements, that is, 60. This is why the chronology of heavenly stems and earthly branches has a 60-year cycle.

Extended data:

Heavenly stems and earthly branches is said to have been invented in ancient times four or five thousand years ago. For example, in the Tang Dynasty, Liu Shu quoted an ancient book in Zi Zhi Tong Jian, saying, "(Huangdi) is a teacher, and he is a teacher." Although Zuo Jiazi is a legend, judging from the names of emperors in Shang Dynasty, such as Yi Tian (Cheng Tang), Waibing, Zhongren and Taijia, the origin of their main branches must be earlier than the Yin Dynasty, that is, they appeared 3,500 years ago.

At first, our ancestors only used the sky to record the days, because the days of a month were carried by the days; Earthly branches are used to remember the months, because ten months a year are matched with ten earthly branches. However, not long after, people felt that if only the heavenly stems were used to record the days, there would still be three days in a month, so they used the method of matching the heavenly stems with the earthly branches in turn to record the dates. Later, the method of recording the day by the earth branch was gradually introduced to record the year, month and time.

References:

Baidu Encyclopedia-heavenly stems and earthly branches