I went on a relaxing trip to visit the Hakone area in Japan recently. Goen no Mori is a ryokan in Yugawara, a famous hot springs area close to Hakone. It also has all-vegan meals.

Dinner was full of delicious preparations of veggies. The dishes change daily at the whim of the chef. All the vegetables tasted very fresh and were well-prepared! There is a salad, rice, and miso soup buffet, too.

These are

There were also steamed vegetables for another main dish. They are simple but delicious.

Breakfast was similar to dinner, with main dishes and
I especially appreciated the side salads, miso soup, and rice. All the ingredients were very healthy, focused on nutrition. The food is good to “reset” with, I think.
There are few vegan Japanese inns and onsen, so I was happy for the experience. If you are going to the Hakone or Atami area, I suggest looking into Goen no Mori.
For more information: http://goennomori.jp/