As early as 2,500 years ago, around the Spring and Autumn Period (770-476 BC), Chinese people determined the winter solstice by observing movements of the sun with sundials. It falls on December 22 or 23.

In the Chinese idea of Yin and Yang, Yin symbolizes feminine, negative and dark qualities of the universe, and yang masculine, positive and fiery qualities, and when something goes to one extreme it then goes to the opposite. Winter solstice in the northern hemisphere is the shortest day and longest night. After it, days become longer, which ancient Chinese thought meant yang qualities would become stronger, so should be celebrated.

The winter solstice became a festival during the Han Dynasty (206 BC-AD 220) and thrived in the Tang and Song dynasties (618-1279). Han officials organized celebrations and it was recognized as a holiday; frontier fortresses closed and business and travel stopped. In the Tang and Song dynasties, it was a day to make offerings to heaven and people’s ancestors, something both emperors and common people did. According to records from the Qing Dynasty (1644-1911), the day was regarded to be as important as Spring Festival (Chinese Lunar New Year).

The kinds of food people eat during Winter Solstice Festival vary due to different local customs.

In some parts of northern China, like Beijing, people eat dumpling soup (huntun) on this day. It’s said that in the Han Dynasty, when Hun tribes attacked China’s borders, two tribal leaders were the fiercest. One was named Hun and the other Tun. So when people made food to offer to their ancestors and celebrate the festival, they called the dumpling soup they ate huntun to show their hatred for their enemy.

In other parts of northern China, such as Henan, people eat dumplings in honor of a famous doctor named Zhang Zhongjing (150-219). Zhang is remembered not only as a brilliant physician but as being very kind to the poor.

According to local custom, one year the winter was so cold that many people in Zhang's hometown of Nanyang suffered from painful chilblains. Seeing that his small clinic was no longer able to accommodate an ever increasing number of patients, Zhang asked his brother to put up a tent in the village square. A large cauldron was placed inside the tent to prepare medicine, in which Zhang had dumplings stuffed with mutton boiled. Every patient got a bowl of the soup with two dumplings, and their chilblains disappeared in a day or two. Zhang's mixture soon became a popular recipe, and when he died, people began to eat dumplings on the day of the winter solstice in his memory.

In northern China, many people eat mutton and dog meat because these are believed to be hot yang foods, bringing warmth to the body and dispelling the cold of yin.

In parts of southern China, people eat tangyuan (rice dumplings), a kind of stuffed small sweet ball of glutinous rice flour. Tangyuan can be used as offerings to ancestors or gifts for friends and relatives. The Chinese word tang (meaning “soup”) sounds like tuan, which means reunion, while yuan means perfect and happy. The entire phrase tangyuan therefore symbolizes "tuanyuan" (family reunion), and eating it at the winter solstice signifies family unity and prosperity. For luck, some families prefer to have pink tangyuan mixed in with white ones.

In other parts of southern China, whole families get together to have a meal of red beans and glutinous rice to drive away ghosts and evil. According to one tale, a man named Gong Gongshi had an evil son who died on the winter solstice. After death, he became a spirit that made people ill, but Gong knew his son was afraid of red beans so he taught people to cook red bean rice to keep him at bay.

People in Taiwan have a custom of offering nine-layer cakes to their ancestors. They make cakes in the shape of chickens, ducks, tortoises, pigs, cows or sheep with glutinous rice flour and steam them in different layers of a pot. These animals all signify good luck in Chinese tradition. People of the same surname or family clan gather at ancestral temples to worship in age order.

Noodles are popular in many areas; as the days get longer there is s saying that each gets longer by the length of a thread. So noodles specially made for the festival are called Long Thread Noodles.