When you want to eat Japanese foods during your travel in Japan, I recommend you to go to izakaya which is a Japanese pub. Izakaya serves many kinds of traditional Japanese foods such as sashimi, sushi, grilled fishes etc. Here are some of the dishes available in izakaya.
Sashimi is a very fresh raw fish sliced into thin pieces and often eaten with soy sauce and wasabi. It is a very common dish in izakaya. The sashimi on the upper left is a young yellowtail. The following in clockwise order are turban shell, tuna, sea bream, flatfish, squid and a small helping of wasabi on the side.
Sushi of grilled mackerel with sliced green onions and ginger root.
A short-neck clam with soy sauce
Grilled sea eel with white pepper and salt
Japanese omelette and grated radish that is usually eaten with soy sauce.