What is the historical origin of the number nine?

Jiujiu, also known as Winter Jiujiu, is a folk solar term in China. The number 9 starts at the end of the solstice in the early winter of the Gregorian calendar 65438+ every year. There is no exact information about when the custom of counting nine originated.

The number nine was very popular in the Southern and Northern Dynasties. "Liang Chao Shu Jing Chu Chun Qiu" records: "The winter solstice is 998 1 day, which is the end of cold." Count nine cold days, that is, from the solstice of winter, count a "nine" every nine days until the "99" of 81 days, and the weather will warm up.

According to the Chronicle of Yanjing, "March 9 to Sunday is a difficult winter." It means that it has entered the coldest stage in cold weather since March 9. "Jing Fang Yizhan" said: "The solstice after winter, the 30th is extremely cold." "The third day after beginning of winter is the coldest day in December from solstice." Later, it was generally considered as the coldest day in March and September.

Why count "nine"? In the traditional culture of Han nationality, nine is the extreme number, which is the largest, largest and longest concept. Nine nines is eighty-one, which is the "maximum" number. Ancient Han people thought that September 8 1 day must be the spring after the winter solstice.

According to the literature, "99" refers to the season in the middle and lower reaches of the Yellow River in China.