Koji is most commonly fermented rice, but can also be made with fermented barley or soybeans. The second is katsuobushi dashi, a soup stock made from water, kelp and dried, fermented bonito or skipjack tuna fish shavings. As fish is one of the primary ingredients, traditional miso soup is not vegan-friendly.
15-minute miso soup with white miso, chopped green chard, green onions, and tofu. Vegan and gluten-free!
Looking through VRG's "Guide to Natural Foods Restaurants," I found less than fifteen. Furthermore, Japanese soup stock, dashi, which contains bonito (fish) extract,. . Just in case, check if they used bonito "dashi" or eggs in the miso paste.