Updated 9/7/18
First off, they have a good selection of vegetable sushi rolls that are vegan. Basically, all of their vegetarian rolls, except the ones that include tempura, are vegan. These include the cucumber roll, avocado roll, CAA roll, shiitake roll and plain fashion roll (avocado, cucumber, spinach, lettuce, asparagus and kanpyo [sweet Japanese pickled gourd]). The only vegetarian roll that vegans should avoid is the Yasai Roll (a Japanese sweet potato that includes tempura—most tempura bases include egg).
For appetizers, we ordered the shiitake roll and the plain fashion roll. Both were good; if we were to only order one, we’d go with the shiitake roll next time. We were also served a simple side salad with ginger dressing (NOTE: the miso soup is not vegan).
For entrees, we ordered the curry rice and the Yaki Soba, which was pan-fried buckwheat noodles with vegetables. Both were tasty. Other options include the zaru soba and the stir-fried vegetables, as well Koto Buki fried rice (if you ask them to hold the egg) and Kotobuki Tofu Teriyaki (if ordered with seasoned soy sauce). There is also one mochi dessert option that is vegan.
With our two rolls, two appetizers, soup and salad, we had a nice amount of leftovers for another meal! Koto Buki is a great place with a delightful atmosphere. We found the staff helpful and willing to check on ingredients for us. We give a strong recommendation for Koto Buki!