This is one of the really traditional easy dishes in Japan. My dad likes it so much. We often eat this dish with the rice, miso soup, grilled fish and Japanese pickles in the morning.
If you make this soy-dashi dressing (Tsuyu) a lot, it can be refrigerated about a week. You can use it for anything like boiled spinach, salad, steamed fish, boiled chicken, and so on.