On the Winter Solstice, the Northern hemisphere experiences its shortest day and its longest night. From then on, the days become longer and the nights become shorter. According to ancient Chinese thought, the “yang,” referring to masculine or positive things, will become stronger and stronger after this day. The weather in China will also enter its coldest phase.

The ancient Chinese considered the Winter Solstice very important. It was treated as an important festival, and there was even a saying that went, “the Winter Solstice is as significant as the Spring Festival.” There are celebration activities for this solar term. As recorded in the Book of Former Han, “On the Winter Solstice, the yang rises and the dao becomes stronger. That’s why we celebrate.” People believed that from this day on, the day becomes longer, the yang becomes stronger and a new cycle begins. Thus, it is an auspicious day to celebrate. It was written in the Book of Jin (Jin Shu) that “the Winter Solstice was celebrated by all counties and officials… The ceremony is second only to that of the Spring Festival.” According to the theory of yin-yang and the five elements, the winter Solstice is the key solar term of the transformation of the yin and yang. In the Twelve Divinatory Symbols, it is referred to as yi-yang-sheng. As described in the Book of Change, “the king secludes himself from the outside world on the Winter Solstice, and business and travel had better stop.”

There are many different customs in China to celebrate the Winter Solstice. In northern areas, people slaughter sheep, and have dumplings or wontons, while southern people eat glutinous rice cakes or noodles. The people in the south of Jiangsu eat fired tofu with onions. People also offer sacrifices to their deceased parents or other relatives.

Formula: [Y*D+C]-L

Key: Y refers to the last two digits of a year, such as 10 in 2010, 08 in 2008, D = 0.2422, L = the number of leap years, 21st century C = 21.94, 20th century C = 22.60.

Example: The date of Winter Solstice in 2088 = [88 × 0.2422 +21.94] - [88 / 4] = 43-22 = 21, so Winter Solstice starts on December 21.

Exceptions: For 1918 and 2021, reduce one to the calculated result.