Liu An (179- 122) was born in Pei County (now Fengxian County, Jiangsu Province), the grandson and son of Liu Bang, and the king of Huainan. Invite guests to write Lie Hong (later called Huai Nan Zi). According to Hanshu, Liu An committed suicide when the rebellion of Emperor Wu of the Han Dynasty was exposed. According to another record, Liu An was enlightened.

According to records, Liu An was the inventor of tofu and many health preserving methods. It is said that Liu An used soaked soybeans to grind into soybean milk for her mother to drink every day during her mother's illness. Liu's illness gradually improved and soybean milk spread to the people. About the origin of tofu, it is recorded in ancient books that Liu An accidentally mixed gypsum into soybean milk when he was making an alchemy in Bagongshan, Huainan, and after chemical changes, it became tofu. At this point, both soybean milk and tofu originated in China, and Huainan, Anhui Province is known as the hometown of tofu in China.

King Huainan is King Jingchu.