From 19 to the day after winter. Three or nine days refers to three cold days from winter to Sunday to everyone's day, which is the coldest period of the year. The specific calculation method is 19 every nine days starting from the winter solstice. The first nine days are called 19, the second nine days are called 29, the third nine days are called 39, the fourth nine days are called 49, and the fifth nine days are called 59, and so on until 99, that is, until the ninth nine days reach 998 1 day. The coldest period of the year is three or nine days.

The coldest period in winter usually occurs after the winter solstice. After beginning of winter, it means that it has entered winter, but it doesn't mean that it has started to get cold. So the heat stored on the surface in the second half of the year still has some energy, so it is not very cold. In winter, the so-called cold is usually not very cold before the winter solstice, but the real cold is after the winter solstice, especially on the third and ninth days.

Moxibustion for three or nine days is a traditional Chinese medicine regimen, which is usually carried out in three or nine days. Sanjiu Moxibustion Best Time Sanjiu Moxibustion is a unique therapeutic method of Sanjiu Moxibustion in winter, which belongs to Tianjiu Moxibustion in TCM therapeutics, just like dog moxibustion in summer.