At the end of the Eastern Han Dynasty, the famous doctor Zhang Zhongjing saw that many poor people were hungry and cold, and their ears were frozen. I set up a medicine shed to apply medicine and gave everyone a food called "Quhan Joule Decoction". After eating, the whole body is hot, the blood is smooth, the ears are warm, and gradually the patient's rotten ears are cured. Every winter solstice, people imitate Zhang Zhongjing to make "Joule", which gradually evolved into the present jiaozi.
Winter solstice, also known as winter festival, Asian New Year Festival and Long Day Festival, has both natural and humanistic connotations. It is not only an important solar term among the 24 solar terms, but also a traditional folk festival in China. Eating jiaozi on the solstice in winter is a long-standing custom in northern China. Jiaozi is a kind of food with balanced nutrition. Jiaozi's harmony of five flavors accords with China people's way of keeping in good health, namely "harmonious skills" and "moderate diet".