Written by Liu An, King of Huainan, during the reign of Emperor Wu of the Han Dynasty
"Hanshu·Yiwenzhi" collectively refers to this type of documents as "Fangzhong".
In 982 (corresponding to the beginning of the Song Dynasty in China), the Japanese Tanba Yasurayi compiled and compiled the Chinese medicine work "Yishin Prescription" before the Tang Dynasty in China and classified it as "Fang Nei"