According to legend, jiaozi was also the invention of the medical sage Zhang Zhongjing. He used to be a satrap in Changsha, where it was particularly cold in winter. Many people are cold and hungry and often get sick in winter. Zhang Zhongjing had a shed set up, put a very big pot, chopped mutton and Chinese herbal medicine into dough, and put it into a stuffed pot to cook. When the dough is cooked, Zhang Zhongjing will give them to the poor around him. After eating, these people feel hot ears and warm bodies, so they call this thing "Joule".
Zhang Zhongjing's behavior of giving him charming ears will last until the New Year. His charming ears help people dispel the cold and resist diseases. People like him very much, so they eat Joule every year to show that they have not forgotten Zhang Zhongjing's kindness.
Besides, Joule tastes good, and eating it in winter is good for your health. Therefore, the custom of eating Joule has been passed down from generation to generation, especially in the New Year. This joule is now called jiaozi. From the Han Dynasty to the present, jiaozi has been circulated for thousands of years. Now we eat jiaozi, which means reunion and happiness, so many families inevitably eat a plate of jiaozi every Spring Festival.