A reduction sauce marinade is a good way to flavor meats and fish. The flavor of a reduction sauce is intense and sauces with an acidic base will easily penetrate the meat.
A reduction of soy sauce, sugar, mirin, and sake is a traditional Japanese sauce that is great on salmon and chicken. To make this simple teriyaki sauce, mix equal parts soy sauce, mirin, sake, and fine sugar over medium heat. As the water evaporates, the sauce will thicken and the flavors will intensify.