Millet and Sweet Vegetable Soup

[from The Cancer Prevention Diet, by Michio Kuchi and Alex Jack, p. 467]

1 cup millet
1/2 finely chopped butternut or buttercup squash
1/2 cup finely chopped carrots
1/2 cup chopped cabbage
1/2 onion, finely chopped
1-inch piece of wakame [sea vegetable sold at Whole Foods or Japanese grocery]
small piece of shiitake mushroom [dried, from Japanese grocery store]
miso (1/2 teaspoon per person) [sold in Whole Foods], or shoyu (several drops) [soy sauce]
Combine ingredients except miso or shoyu with 3 times as much water. Bring to a boil, lower heat, and let simmer about 30 minutes or until done. Toward the end of cooking, season lightly with miso or shoyu and simmer another 3 to 4 minutes.