NOT so Big in Japan - being a vegetarian

Biggest problem I'm facing. Being a vegetarian it is really hard to get a cooked meal that is suitable.
The past weeks I'm very much going on sandwiches (bread and cheese ones predominately) and it kind of feels not so well. I already had some mishaps with food...It is very frustrating actually. For a country that came to eat meat only some 80 years ago it is sort of amazing how much less vegetarian Japanese cuisine is...Of course there is a lot of fish, but fish is also life, so I don't know (yet) how Japanese being Buddhists managed to circumvent the killing of fish 'sin' which is major in their diet...
Half of my master thesis talks about how killing and eating fish has bad karmic influences, it is kind of ironic I am now in this country that kills and eats a lot of fish.
I am not judging. With the situation of Japan, it being an island, topography, geography, etc. it is perhaps natural that they have not become complete vegetarians.

What I wanted to say (share)is that being a vegetarian in Japan is really not easy.
I don't have time and energy to cook and I'm still to find alternatives to eating predominately sandwiches...
Hm, let's see how it evolves...
There must be a solution...