What do you mean by opening eight characters?

The eight characters are the birthdays called by China heavenly stems and earthly branches, and there are eight characters in total, such as Jiazi Year, Ugly Month, Ugly Month, Bingyin Day and Ding Mao Day. In the ancient calendar of China, A, B, C, D, E, Ji, G, Xin, Ren and Gui were called "ten heavenly stems", while Zi, Ugly, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai were called "twelve earthly branches". Ten branches and twelve branches are matched in turn to form sixty basic units, and they cooperate with each other in a fixed order to form branches and branches. 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: From Jiazi, but the punctuality branch is fixed, every day 12 hours.

The traditional saying is that if two people want to get married, they must first look at the eight characters, that is, like each other, don't like each other, or find a way to solve it.