Soy sauce was invented in China about 2000 years ago where it is an essential ingredient in Chinese cooking. Soy sauce is now used widely in most S.E Asian countries especially in Japan, Thailand and Indonesia. In Japan, Soy sauce is known as “Shoyu”, and many different types of Soy sauce are available including Tamari which is considered to be the original Japanese Soy sauce. Tamari is usually wheat-free. The Japanese brand name Kikkoman is famous throughout the World and offers a large range of Soy sauces. You should note that Soy sauce produced in different countries can have widely differing tastes and degrees of saltiness.
Whilst Chinese Dark Soy sauce has been shown to have large amounts of anti-oxidants and help prevent cardiovascular diseases, there have been some health concerns with some Soy sauce made from Hydrolyzed Soy Protein because of the amounts of possible cancer inducing chemicals. Soy sauce may not be suitable for those people on a low sodium diet because even the low salt varieties of Soy sauce still contain substantial amounts of salt. People with a wheat allergy should avoid Soy sauce made with wheat.