Combine the dashi, soy sauce, mirin, and sugar in a saucepan and bring just to a boil. Stir in the bonito flakes and immediately remove from the heat. Wait about 10 seconds for the flakes to get thoroughly soaked, and then strain. Let liquid cool to room temperature. Serve with cold soba noodles for dipping, along with scallions, grated daikon, quail eggs and natto if you have a taste for it.
c.1997, M.S. Milliken & S. Feniger, all rights reserved