Place water, kombu, and shiitake in a saucepan. Bring to boil, cover and reduce the flame to medium-low. Simmer about 10 min.

Remove kombu and shiitake and set them aside for use in future dishes. Reserve the stock water as well.

Wash buckwheat and place it in dry skillet. Roast several minutes on a low flame, stirring constantly to prevent burning and to roast evenly.

Bring the stock water to a boil and add buckwheat and a pinch of salt. Cover and reduce flame to low. Simmer about 20 min or until all water is gone.

Place buckwheat in a wooden bowl. 

Garnish with diced greens.