When you roll some rice to make a triangular, cylindrical or a circular shape and put ingredients inside, it is called an “onigiri”（Rice ball）. Another name for it is “omusubi.” It has existed in Japan since ancient times (in one theory, as early as the Yayoi Period). There are similar types of food in other parts of Asia, but those are usually for emergencies or simply because they are easy to carry. However, in Japan, even if it is commonly because they are portable also, they are regarded as easy fast food. This is due to the fact that the Japanese rice does not get hard after time.

So there is less of the “even if it’s hard, I have to eat it because there’s nothing else to eat” factor in Japanese onigiri. The most common way to wrap an onigiri is with seaweed, ut the toasted onigiri spread with soy sauce or miso paste is popular too. There are many types of ingredients you can put in an onigiri. You can use anything you use to eat rice with, but among them, there are extremely popular ingredients. Currently the onigiri is one of the typical foods available at convenience stores in Japan. (Recently it is true in Korea also). One of the most popular onigiri at the stores is the tuna mayonnaise. The combination of the rice and the mayonnaise, along with the tuna, has made many fans of this onigiri. Another popular one is the spicy cod roe onigiri. (Spicy cod roe is cod eggs mixed with red pepper).