San-J International is a fully owned subsidiary of San-Jirushi Corporation who is the largest manufacturer of tamari in Japan. Tamari was originally invented in China and brought to Japan in the 7th century A.D. It is made when soybeans, exposed to microbiological cultures and salt, turns into a dark red paste known as miso. Tamari literally means, "that which accumulates" because it is the name given to the protein rich liquid that accumulates during the miso ripening process. Gradually, the manufacturing of soy sauce became more commercial and the traditional methods were replaced by less time consuming and more cost efficient methods. Miso was replaced by a thinner "mash" and the end product was much higher in brine than miso solids. The content changed from being all soy to half soy and half wheat.
The San-Jirushi Corporation was founded in 1804, and it marked the incorporation of a tamari and a miso company that had been in business for almost 200 years. The current President, Nobuyoshi Sato is the seventh generation of the Sato family to manage the company.