Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   1      4" square     dried kombu -- (kelp), cleaned with
                        -- a damp, cloth
     2/3  cup           bonito flakes
     1/3  pound         enoki mushrooms -- reserve a few
                        -- for garnish
   2      tablespoons   miso
   2                    scallions -- finely sliced

Preparation:

Combine the kombu and 4 cups water in a pot. Bring to a boil. Remove the kombu and discard. Add the bonito flakes and stir well; remove from heat. Let the flakes settle to the bottom of the pot. Strain the stock through a fine sieve, discarding the bonito flakes. Return the stock to the pot and add the mushrooms. Cook over moderate heat until the mushrooms have softened (3 minutes or so). In a small bowl, dissolve the miso in a ladleful of the stock. Add the dissolved miso to the soup pot and stir to combine. divide the soup among four bowls and sprinkle with reserved enoki and scallions.