Bring water and shiitake to a boil in a soup pot. Lower the flame, cover and simmer for 10 minutes.
Add the bifun and cook over medium-high heat, uncovered, for 2 minutes.
When the bifun are tender, turn the heat to very low, add the wakame flakes and stir in the miso. Simmer 2 minutes Place in serving bowls and garnish with scallions.
Per serving - 219 calories, 1 g fat (3% calories from fat), 9 g protein, 55 g carbohydrate, 5 g fiber, 0 mg cholesterol, 474 mg sodium