Later, he retired in his later years and returned to Nanyang. It snowed heavily. He saw that the life of ordinary people in the world is so miserable, so many people are still suffering from cold and hunger, and many people's ears are actually frozen.
Zhang Zhongjing, who couldn't bear the sufferings of the people, called his disciples to set up a medicine shed in Wancheng, then set up a cauldron, cooked mutton, pepper and other cold-dispelling ingredients, took them out and chopped them, then kneaded them into ears with dough, cooked them in a pot and gave them to the people as "cold-dispelling Joule soup".
It's amazing that many people's ears are rotten after eating this "cold-dispelling Joule soup". So this method gradually spread, and the people did not say "Joule soup for dispelling cold", but gradually evolved into "Joule soup", "Joule soup" and finally became "Jiaozi".
In memory of the benefactor, people eat jiaozi every year on the day when Zhang Zhongjing cooks soup. It happened to be the solstice of winter.