Sweet soy sauce is a sweetened soy sauce that is viscous, aromatic, and significantly less salty than other varieties. Sweet soy is great to use as a dip but is primarily used for adding gloss, body, and a touch of sweetness to dishes.
Uses: Make your favorite stir-fry dish with the addition of sweet soy for deep caramelized umami. Glaze your favorite roasted or seared meats (such as steak) by adding sweet soy, a pat of cold butter, and basting.
Adding sugar to regular soy sauce is not a good substitute for sweet soy.