When did the head drop surgery begin?

The first day in Fu Tou this year is July 16.

"The number of the third watch is in summer" is the basis for determining lodging. This means that from the summer solstice, there will be a third Geng day, which is the first day of accommodation.

For example, this year's summer solstice is June 2 1 day of the Gregorian calendar, and the first "Geng Day" is June 26. The second "Gengshen Day" is July 6; The third "Hundred Days" was 16 July, so 16 July became the first day of illness and the beginning of dog days.

Fu Tou mechanism

"Fu" means being forced to hide underground by Yang Qi. Three days can be divided into morning, middle and evening, and its date is determined by the coordination of solar terms and solar terms in the calendar.

According to China's traditional calculation method, the third and fourth Geng Day from summer to the future are the start dates of junior high school and middle school respectively, and the first Geng Day after beginning of autumn is the first day of the last Geng Day.

Because every Geng day is 10 days apart, the stipulated time of the first day and the last day is 10 days. Because the third Geng day (early autumn) after the summer solstice solar terms appears sooner or later, the days of early autumn are long and short.