Japanese cuisine is incredibly diverse, with regional and seasonal impacts on almost everything..Cost varies hugely too, it can be downright expensive ( a restaurant near me serves a 125 g steak for around $1000 USD) or ridiculously cheap (Tonkatsu set $10 USD) ..
What i think is different is the quality of the food and its preparation even in cheap restaurants, that may only serve one thing, it is commonly beautifully and carefully prepared.. So you can eat well here cheaply, even in big cities, but you need to get away from tourist restaurants to do so..
I have many favorites and every meal out is another adventure because the menus change seasonally.
Anyway here are some of my favorites, in no particular order and also not a final list – not even close, I have many, many more.. Most of these from restaurants around the Otawara or Nasu area..
Tonkatsu – mostly a pork fillet or pork loin coated with bread crumbs and deep fried. Often served with shredded cabbage and a sort of pasta salad in my favorite restaurant. It is eaten with a Tonkatsu sauce (sort of Worcestershire) mustard and a slice of lemon. You can get it in sandwiches too and with a curry sauce – but plain old Tonkatsu is one of my favorites.