one of the reasons that made me give up living in Japan is how surprisingly difficult it is to get vegan food, especially in the Japan I like the most (mountain villages in Iwate, the Tsugaru strait, Akiyama-gõ etc.).
to make matters worse, all those kind and sweet old people are very proud of their food culture and want to offer you all sorts of locally produced cuisine, and even if you refuse the seafood everything that's savoury has bonito in it and everything that's sweet and modern (not wagashi) has milk in it, and there's no way to explain why you don't eat animals without breaking their hearts. despite the Buddhist vegetarian tradition, if you ever get intimate enough to explain "vegan for the animals", it comes off as foreing criticism of lifestyles.
there are of course Japanese vegans and the kind of stuff you can get in vegan haunts in a big city is mind-bogglingly awesome, Japanese cuisine is almost scary in how good it is. but it's different than going into a Lawson and there's a million snacks and none of them are plant-based, and it doesn't soften the difficulty socially integrating with the food culture.
then you add all the times I had to make up some excuse to refuse an invitation for onsen, despite invitations for onsen being a great way of bonding and despite my love for onsen, because I'm not fit for onsen on tattoo grounds alone, nevermind doing public nudity with a trans body... there's even a videogame about it, it's kind of a whole thing.