During the Xianfeng period, Hengshui people operated two kinds of snacks in Xianyukou, Beijing, one was "Jizhou Caoji Donkey Meat" and the other was "Raoyang Tofu Brain". They are very close to each other, and the food they manage is complementary, so people who come to eat tofu brain often eat donkey meat with big cakes (or sesame cakes). People who come to eat donkey meat must drink a bowl of tofu brain to feel carefree. They help each other and their business is booming. Jizhou's "Cao Ji Donkey Meat" originated in Beijing. (A Brief Introduction to "Time-honored Beijing Literature and History Materials")