From The Food Encyclopedia by Jacques Rolland and Carol Sherman
Also shoya, soya sauce. A condiment developed by the Chinese in the early 13th century, during the Sung dynasty, to add flavor to rice, oil, vinegar and tea, it quickly became a dietary staple of the poor. Soy sauce, called shoyu in Japan, is a thin almost black sauce used extensively in the East, largely in place of salt. It is made by fermenting soybeans with roasted wheat or barley and salt, then filtering, pasteurizing and bottling the liquid. The sauce's consistency can range from very thin to very thick. The Japanese make a light soy sauce, which has a thinner consistency and a saltier flavor than darker varieties. Japanese soy is preferred when a darker sauce will ruin the appearance of a dish, or when a lighter flavor is desired, especially when serving seafood. Dark soy sauce is popular throughout Asia. It is slightly richer than light soy sauce and tends to have a chocolate brown color, and a pungent, rather than overly salty flavor. Mushroom soy sauce is a dark soy sauce from China, made with straw mushrooms with a deep rich flavor. Tamari is a Japanese soy sauce that has a rich texture and intense flavor. See also tamari.
