Soy sauce (soya sauce) is a dark brown liquid made from fermented soybeans (soya beans), roasted wheat, water and salt. Soy sauce is common in the cuisines of Japan, China, Korea, Indonesia, and Malaysia.
Japanese soy sauce tends to contain more wheat than Chinese soy sauce, giving Japanese soy sauce a slightly sweeter taste.
Soy sauce is shelf-stable because it contains added salt, alcohol, or sodium benzoate. Since alcohol quickly boils off when stir-frying (a typical use of soy sauce), an alcohol-based soy sauce is preferable when using copious amounts.