Liu An, the grandson of Emperor Gaozu Liu Bang, was made King of Huainan in 164 BC, with Shouchun as its capital. When he was making an alchemist, he once mistakenly put gypsum into Dan's mother liquor, that is, soybean milk, and the chemical change became tofu. Tofu came out. Liu Anshan visited Zen and was good at making friends with monks. One day, he tasted the tofu made by the monk and found it very new. He decided to study the method and technology of making tofu in depth. Set up a tofu production workshop to train professional tofu producers. In the process of production and operation, the production equipment and technology have been gradually improved, and the quality of tofu has been improved. At the same time, the technology of tofu making was passed on to others and gradually spread to other areas. The production technology of tofu was introduced to Japan in the Tang Dynasty, and then to Southeast Asia and other countries and regions in the world.