How to calculate the initial accommodation?

It was determined according to the "Chronology of Branches and Branches" in ancient China.

The first lodging is the first lodging of "three volts". Its date is from the third Geng day to the day before the fourth Geng day. Because every Geng day is separated by 10 days, the initial lodging time is 10 days. The word "V" in three volts has two meanings. First, it means that Yin Qi was forced by Yang Qi to hide underground; Second, it means the weather is too hot to move. Its climatic characteristics are "high temperature and high humidity".

"V" means being forced to hide underground. There are three kinds of fu: initial fu, middle fu and final fu, and their dates are determined by the solar terms and dates of the dry branch calendar. According to China's traditional calculation method, the third and fourth Geng days from summer to the future are the first (head) and middle start dates respectively, and the first Geng day after beginning of autumn is the last first day.