Make the sauce by combining 1 tablespoon mirin, 1 tablespoon sake, 5 tablespoons soy sauce, sugar, and umami seasoning in a frying pan. Make the sauce ahead of time and let it cool.
Mirin 1 tablespoonSake 1 tablespoonSoy sauce 5 tablespoonsSugar to tasteUmami seasoning (Hi-Me) 6 shakes