Cold Noodles with Dipping Sauce (Soba)

1 (8 1/2 ounce) package soba granules (buckwheat noodles)
1 cup water
1/4 cup soy sauce
3 tablespoons granulated sugar
1/4 teaspoon hon-dashi (dashi granules)
1 scallion (with top), thinly sliced
1 teaspoon grated ginger root
1 tablespoon wasabi powder
1 tablespoon water

Cook noodles as directed on package; drain. Cover and refrigerate until chilled. Heat water, soy sauce, sugar and hon-dashi to boiling; remove from heat. Cool; stir in onion and gingerroot. Mix wasabi powder and water to a paste. Divide noodles among 8 small bowls. Pour soy mixture into 8 small dipping bowls.

Serve with wasabi paste. Stir small amounts of wasabi paste into soy mixture to taste.