Very good and cheap sushi. Quality is high and prices are human. :)
No really a supermarket but small shop where you also can buy some Japanese things. Most of the people come to here because of the sushi.
A spectacularly dingy little shop, featuring plastic tat in the windows and hospital mortuary white-tiling. But the food is the thing, and this place sells delicious, authentic Japanese Sushi at a reasonable price. There's an option to eat-in by propping your elbows on one of several tables in the back, where you can admire the imported soy sauces and noodles whilst chewing on your food (and resist the urge to shoplift). Or just take-out and chow-down, preferably in the sunshine on the banks of the nearby River Main.
This is not a restaurant, but a shop that also serves food. No seat. No toilet. The place is really crowded. They must be paying Tokyo rents to have that little space. But the sushi has a high quality if you are not claustrophobic and are ready to wait near the cash register.