Winter Solstice

The winter solstice is an important solar term in Chinese lunar calendar. It is also a traditional festival for the Chinese nation. The winter solstice is commonly known as "number nine, winter festival", "long festival", "Asian year" and so on. As early as 2,500 years ago
In the Spring and Autumn Period, China had already observed the sun with Tuyu and measured the winter solstice. It was one of the earliest days of the 24 solar terms and its annual Gregorian calendar was December 21-23.