Why are the hottest days in summer called "dog days"?
The "Three Volts" days are determined according to the ancient Chinese "Stem and Branch Day Method".
The "stem and branch date method" is a method of recording the sequence of days using the stems and branches. The stems and branches are the ten heavenly stems such as Nail, Yi, C, D, Wu, Ji, Geng, Xin, Ren, and Gui, and Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai, etc. Twelve earthly branches. The stem and branch calendar method is the same as the stem and branch calendar method. The sixty Jiazi that match the stems and branches are used to record the day sequence. From the beginning of Jiazi to the end of Guihai, sixty days constitute a week, and the cycle is recorded.
The third Geng day after the summer solstice (referring to the day with the word "G" in the calendar of stems and branches) is the first Geng day, the fourth Geng day is the middle Geng day, and the first Geng day after the beginning of autumn is It is the last volt, and together they are called the "three volts".
The Geng day repeats every 10 days, so the first fall lasts for 10 days, the middle fall lasts for 10 or 20 days, and the last fall lasts for 10 days. Why are Zhongfu divided into 10 days and 20 days?
This is because if there is only one Geng day between the summer solstice and the beginning of autumn, the period of Zhongfu will be 10 days, and if there are two Geng days, it will be 20 days.
When the middle period lasts for 20 days, it is usually called the fourth period among the people, but in fact it is still the third period, but the middle period is longer. What does "volt" mean?
In the hottest days of summer, Yang Qi reaches its peak, and then turns from strong to weak, ushering in the cool weather of autumn. At this time, the heat of the sun completely envelopes the Yin energy, so the Yang energy is at its peak and the Yin energy is hidden. Therefore, the "volt" in Dog Days means that the yang energy is at its peak and the yin energy is hidden. In the dog days of summer, people always feel like they are sweating like rain. Little do they know that the naming of dog days already contains the expectation and association of shade. Summary:
"Winter diseases are treated in summer". People with yang deficiency or yin deficiency can eat mutton and apply dog days of summer during the hottest period of summer, so that the body can rely on external influences. The heat of Yang Qi and medicine will force out the cold evil hidden in the body to achieve the purpose of treatment.
Dog Day is the hottest day of the year, and the hottest day of Dog Day is Zhongfu. At this time, people want to cool off from the summer heat, schools have summer vacation, and ancient private schools also have a vacation, which is called "summer festival".