What do you mean by opening eight characters?

The eight characters are the birthdays, years, months and days called by heavenly stems and earthly branches in China, such as the words * * * in Jiazi. 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. From Jiaziyue to Guihaiyue, * * * sixty Jiazi, 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 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.