How to calculate the three Geng of summer solstice?

The calculation method of three Geng's on the summer solstice: Three Geng's will count volts on the summer solstice, and it will be ten days and one volt.

The calculation method of three Geng's on the summer solstice: Three Geng's will count volts on the summer solstice, and it will be ten days and one volt. The time between two Geng days is 10 days, and the time between the first autumn and the summer solstice is not necessarily at least 2 1 day, but at most 30 days.

The date of the dog days is determined according to the date of the solar term and the date of the dry branch. According to the provisions of the lunar calendar, the number of volts does not start from the solstice in summer. The so-called "three nights in summer" means that the third Geng day is the first night, the fourth Geng day is the middle night, and the fifth or sixth Geng day is the last night, which is the so-called "three nights".

The ambush itself is the day when people "kill dogs" to worship their ancestors, and the word "Geng" itself evolved from Betelgeuse, which is Orion.

Introduction to the third watch:

The third watch, which is the standard for China to start in the dog days of the lunar calendar, "The third watch will enter the summer solstice". It means counting from the solstice in summer to the third Geng day, which is the first day of the first autumn. In ancient China, the "trunk-branch calendar" was popular, and 60 groups of different names were used to record dates with 10 heavenly stems and 12 earthly branches, which were recycled.

The day with the word "Geng" is called "Geng Day". The word "Geng" in Geng Day is the seventh word in "A, B, C, D, E, Ji, G, Xin, Ren, Gui" 10 day, and it is repeated every 10 day.

According to the dates of trunks and branches, the third Geng day is the first day of lodging, the fourth Geng day is the first day of intermediate lodging, and the 1 Geng day after beginning of autumn is the first day of last lodging. When there are four Geng days between the summer solstice and the beginning of autumn, the middle part is 10 days, and when there are five Geng days, the middle part is 20 days. The emergence of Geng Day will affect the length of midsummer, so some years are 30 days, and some years are 40 days.