SoyThe humble soybean (daizu) is used to make a wide variety of foods and flavourings. Soybeans and rice are used to make miso, a paste used for flavouring soup and marinating fish. Together with soy sauce (shoyu), miso is a foundation of Japanese cuisine.
Tofu is soybean curd and a popular source of protein, especially for vegetarians. These days, even tofu donuts and tofu icecream are available.
Natto, fermented soybeans, is one of the
healthiest but also the most notorious item on the menu. With a pungent smell and sticky, stringy texture, natto is easy to hate straight away. Japanese people themselves tend to either love it or hate it. It is usually served with chopped onions and a raw egg and mixed into a bowl of rice. (all text directly from: http://www.japan-zone.com/culture/food.shtml)