Add all of the ingredients (tahini, soy sauce, mirin, rice vinegar, sugar, Kewpie mayonnaise, red miso paste, dashi powder and sesame oil) into a small mixing bowl.
6 tbsp tahini, 2 tbsp soy sauce, 2 tbsp mirin, 2 tbsp rice wine vinegar, 2 tbsp sugar, 4 tbsp Kewpie mayonnaise, 1 tsp red miso paste, 1/2 tsp dashi powder, 1/2 tsp sesame oil