Shizen Ya requires reservations because it has only 7 tables, and some of them are only for two people. It may be the smallest restaurant I've ever seen. The food is great though, especially if you are vegan or paleo -- lots of great vegan and organic choices. The size of the restaurant made me feel a little claustrophobic though, and you do pay extra for the quality of the food (organic). If quality and health are important to you and you don't mind paying a little more for it, this is your place.