Mentsuyu is a flavorful Japanese sauce that is commonly used as a seasoning and condiment in many traditional Japanese dishes, or as the base for udon and soba noodles. It consists of varying amounts of soy sauce, strong sake wine, and the slightly sweeter mirin, combined with dry skipjack tuna flakes.
The ingredients are shortly boiled, the mixture is cooled and strained, and it is then immediately ready for usage. Mentsuyu sauce is the essential part of many Japanese dishes, but it is mainly used as a kaketsuyu sauce poured hot over noodle dishes, or as a cold tsuketsuyu dipping sauce.