How to calculate the birthday?

Generally speaking, the lunar calendar is used. You know that the time of the solar calendar can be calculated, and the branch representation of the lunar calendar is eight characters.

But strictly speaking, the constellation is based on the lunar calendar. That is, it is neither a lunar calendar nor a solar calendar. It is based on 24 solar terms. One month before the festival is the last month, and one month after the festival is the next. If someone was born on the 10th day of the first month of this year, if beginning of spring is in November, the column is still last year, and the column is still the ugly month of last year. If he was born on February 25th, 65438 this year, many softwares are simply calculated according to the lunar calendar, which should be quite wrong strictly.