The Dōngzhì Festival or Winter Solstice Festival is one of the most important festivals celebrated by the Chinese during the period of 21-29 of December.
The origins of this festival can be traced back to the yin and yang philosophy of balance and harmony in the cosmos. After this celebration, there will be days with longer daylight hours and therefore an increase in positive energy flowing in.
In southern China the Dongzhi Festival is a time for family to get together to make and eat tangyuan, these are small balls of rice, which symbolize reunion. They are made of rice and flour and normally brightly colored as either pink or green. Each family member receives at least one large tangyuan in addition to several small ones. They are cooked in a sweet soup or savory broth with both the ball and the soup/broth served in one bowl. It is also often served with rice wine containing whole grains of rice and Osmanthus flowers, called jiuniang.
In northern China its typically dumplings on Dongzhi, its origins can be traced to Zhang Zhongjing in the Han Dynasty. On a cold winters day he saw the poor suffering from the bitter weather, their ears blue with cold, so he ordered his apprentices to make lamb dumplings for the poor to keep them warm, to keep their ears from turning blue.
As the dumplings were shaped like ears, Zhang named the dish "qùhán jiāoěr tāng" or dumpling soup that expels the cold. From that time on, it has been a tradition to eat dumplings on the day of Dongzhi.
Traditions also require people with the same surname or from the same clan to gather at their ancestral temples to worship on this day, and then have a grand reunion dinner following the sacrificial ceremony.
The festive food is also a reminder that celebrators are now a year older and should behave better in the coming year. Even today, many Chinese around the world, especially the elderly, still insist that one is "a year older" right after the Dongzhi celebration instead of waiting for the new year.