What is the definition of plum blossom becoming plum blossom?

A friend asked me if I was in May these days. I said that meteorological significance has specific indicators. The traditional entry and exit of plums is related to heavenly stems and earthly branches. The main basis is as follows

Traditionally, in China, the determination of plum entry and plum exit is based on the combination of solar terms and branches. According to the calendar, the first third day after mango seeds is plum blossom, and the first last day in Xia Hou is plum blossom. If the weather on the day of canopy is C, it is designated as entering plum blossom, and if the ground branches on the day of light summer are not, it is designated as leaving plum blossom.

For example, there was a slight summer heat on July 7th 1993, and it just fell on July 13, so the plum blossom date of 1993 is July 13. July 7, 200 1 year is a light summer, and the light summer after July 19 is not a branch of the earth. According to the calendar, the plum blossom date of 200 1 should be July 7th instead of July19th.

It is very simple to calculate the chronology of trunk and branch from the known years: the number of years is reduced by 3, the remainder is divided by 10, and the remainder is divided by 12, which is the earthly branch.