Just had a lovely meal here with my family. They serve meat but have various vegan options. The lunch plate (1100 yen) has a meat/fish and a vegan option, and the contents change every week, but the number offered each day are limited. They have a veg curry on the menu too. It's all quite simple Japanese home cooking style - understated but delicious. It's also very child friendly, there is a kids' plate (600 yen) and there are two high chairs and some picture books. The menu is only in Japanese but the staff seemed very nice and I'm sure if you ask for the "veggie teishoku" or say "vegetarian?" and look hopeful they would help you out ;)
It's quite small (only 4 tables) so would recommend getting there at opening time or going outside peak meal times to guarantee getting a seat. You can give them your name and number and they will call you when a table becomes free. My husband enjoyed the fish dish (side dishes were all the same as the vegan plate) but his one complaint was that it wasn't quite enough food for him.
Overall though we had a great meal and will definitely go back in the future!Pros: Japanese-style vegan food, Nice atmosphere, Child friendly
Cons: No English, Small portions?, Not many seats