It's all about tofu at Tousuiro
I've recently written about the difficulties of traveling to Japan as a vegetarian and introduced some of my favorite vegetarian-friendly restaurants in major tourist destinations. As many purely vegetarian and vegan restaurants don't focus on Japanese cuisine alone, it can be a challenge to find a place that caters to vegetarian guests who want to experience traditional Japanese food. For this reason, several of my restaurant recommendations weren't strictly vegetarian, but offered enough choices to give vegetarian and vegan travelers a great taste of authentic Japanese cuisine.
A well-known staple in vegetarian dishes is tofu, made from soy milk. Tofu gets a bad reputation of being bland and boring among non-vegetarians. In the wonderful city of Kyoto, one restaurant's "mission" is to convince you of the bean curd's versatility. That restaurant is Tousuiro.
Tousuiro operates two branches in Kyoto, one in Gion and one in Kiyamachi street. While the restaurant in Gion is located in a charming old machiya townhouse, the one in Kiyamachi (between train stations Sanjo and Kyotoshiyakusho-Mae north of Pontocho alley) features a terrace over the Kamogawa. Dining on tatami mats under the stars, guests can enjoy great views over the river. (And if you're really, really not fond of tofu, you can find several restaurants nearby with equally charming terraces.)
Tousuiro's focus on tofu (chilled, boiled, fried, grilled, sweet, savory, in ice-cream form and more) makes it easy to accommodate a vegetarian or vegan diet, even though the menu is not strictly vegetarian. The Gion branch offers a vegan menu at advance request, but when we visited the Kiyamachi branch, it wasn't too complicated to change the soup (containing dashi fish stock) to a different, vegan course, either. Be sure to communicate clearly what you can and cannot eat, saying you're a vegetarian might not be enough. If in doubt, printing out these info cards before traveling to Japan might help.
Dining at Tousuiro isn't the cheapest option in town, but the experience of enjoying all the elaborately prepared different courses at such a special location was well worth it. Prepare to spend some time there if you order a full menu, which consists of several smaller courses, and be sure to make a reservation if you want to sit on the terrace at Kiyomachi branch, as these spots are popular in summer (extra charges for the terrace apply).