Phu quoc fish sauce waters around The island are rich in seaweed and plankton which provide food for the anchovy population. However, it only since the late 1950s that the product has been recognized outside of its home island, reaching its zenith of popularity between 1965 and 1975. With increasing government subsidies of many industries in the period from 1975 to 1985, the local fish sauce craft lost market share to larger competitors, but in recent years, the popularity of the authentic Phu Quoc product has been rebounding. In 2012, Phu Quoc fish sauce was granted a European Union Protected Designation of Origin (PDO)
Soy sauce books: "Shanjia Qinggong" (山家清供) and "Pujiang Wushi Zhongkuilu" (浦江吳氏中饋錄) during the Song dynasty (960–1279 AD). Like many salty condiments, soy sauce was originally a way to stretch salt, historically an expensive commodity. During the Zhou dynasty of ancient China, fermented fish with salt was used as a condiment in which soybeans were included during the fermentation process. By the time of the Han dynasty, this had been replaced with the recipe for soy paste and its by-product soy sauce, by using soybeans as the principal ingredient, with fermented fish-based sauces developing separately into fish sauce. The 19th century Sinologist Samuel