According to legend, when Song Taizu Zhao Kuangyin was frustrated, he lived in poverty and fell on the streets of Chang 'an (now Xi 'an). One day, there were only two pieces of steamed buns left on me, and I couldn't swallow them because my husband was hard. As it happens, there was a mutton shop cooking mutton by the roadside, so he went to beg for a bowl of mutton soup so as to soak the steamed buns soft before eating. Seeing his pity, the shopkeeper told him to break the buns and pour a spoonful of hot mutton soup to soak them. Zhao Kuangyin took the bubble good steamed bun, big eat it, eat his whole body fever, sweating on his head, hunger and cold all disappear. Ten years later, in 960 AD, Zhao Kuangyin became the founding emperor of the Northern Song Dynasty, known as Mao. On a tour of Chang 'an, I passed by the mutton shop in those days, and the aroma was overflowing. I couldn't help thinking of eating mutton soup and making buns ten years ago, so I stopped the car and ordered the shopkeeper to make a bowl of mutton soup and buns. The shopkeeper panicked. He didn't sell buns in the shop. What should he make? Ask his wife to bake some cakes at once. When the cake was baked, the shopkeeper saw that it was dead (unfermented) and unfamiliar. Afraid that the emperor would get sick, he had to break the buns into pieces, pour mutton soup and cook them, put on a few large pieces of mutton, carefully mix the seasonings, and then serve them to the emperor. Zhao Kuangyin praised it after eating, and immediately ordered his followers to give him a hundred taels of silver. It spread like wildfire and spread all over Chang 'an. So more and more people come to the store to eat mutton soup and steamed buns, forming a unique flavor food in Chang 'an. Su Dongpo, a great writer in the Northern Song Dynasty, once wrote a poem of praise that "there is bear wax in the dragon, but mutton soup in the Qin Dynasty".