It pays to be hungry in Japan, you should eat every scrap, it is considered bad manners to leave even a grain of rice. Here are a few more tips which will make your meal much more enjoyable.
If you are eating a rice dish, you should hold the rice bowl in one hand and scoop the rice into your mouth with the chopsticks. Never spoil the rice by pouring soy sauce or the like over it as rice is meant to be a pure food.
Sushi, on the other hand, should be eaten with soy sauce, but only take what you will use. You must pour the sauce onto a plate then dip your sushi in. With the last pieces of sushi, make sure you soak up the remaining sauce to leave a clean plate. You can use your fingers or chopsticks to eat sushi, but remember you could offend the sushi chef if you remove ingredients or add anything other than soy sauce like wasabi to the meal. Remember the sushi chef is considered an artist.
You need to respect the sashimi chef too, he isn’t too keen on you using too much wasabi or ginger on his prized dish. You should only use a little, the flavour should be all about the fresh fish and rice, not the condiments.
Miso Soup, the delicious soy and seaweed soup, is best drunk straight out of the bowl like a cup, you may catch the floating pieces of soy with your chopsticks.
Noodles are your time to make a little noise, slurping is not a problem as long as you don’t sound like the farmers pig, just do it as much as the people around you and you will fit in just fine, but don’t burp as that is offensive. The secret of eating tasty noodles is scooping them up with your chopsticks while sucking them down. If no spoon is provided, it is still polite to finish the soup at the bottom of by drinking it like a cup.
Curries are best eaten with a spoon, it is ok to use your chopsticks to grab the big bits, but you will find a spoon does a bit better job.
It is extremely rude to leave your chopsticks vertically in a bowl of rice or anything else for that matter. The Buddhist funeral ceremony does this and no one else should do this with the chopsticks. The ceremony also passes the cremated bones to different people via chopsticks so you shouldn’t pass food like this either.
Other than eating ice-cream or standing at a food bar counter it is considered bad manners to eat anything while standing or walking in the street. You should be seated when eating. Fast food like hamburgers etc are all eaten while seated, you never see anyone walking down the street eating a burger or drinking a drink.