A plum (ume) onigiri
Onigiri are so well-loved you can buy various themed goods and souvenirs...
Onigiri on the shelves in a konbini
A grilled salmon-filled onigiri
How cute! Onigiri for children are often decorated
This triangular-shaped rice treat will make anyone appreciate geometry!
Anyone who has already traveled to Japan will have noticed in konbini aisles or on the menus of izakaya, these small triangular rice balls (yes, that's possible) wrapped in a sheet of seaweed, or nori in Japanese.
Traditionally, onigiri are filled with salty condiments and/or cured ingredients that keep well (including umeboshi, salted plums). But with modern technology helping to keep onigiri cool until they're ready to be eaten, they can now be stuffed with tuna mayonnaise or raw fish.
Very cheap (from ¥100 in most konbini) and nourishing, onigiri are comparable to sandwiches, but are usually more of a snack: eaten on the run, between appointments, or during a family outing, onigiri are excellent picnic food.
However, the opening of a onigiri from a konbini may be difficult for the uninitiated. Onigiri are actually doubly wrapped in plastic, the first layer separates the seaweed sheet from the rice to keep it dry and crisp, and the second is to protect the onigiri as a whole. You must therefore remove the two layers carefully, so as not to tear the seaweed or break the onigiri. This video will help you understand how to unwrap an onigiri:
As for flavors, it can sometimes be difficult to navigate, especially when it's written in Japanese. Here is a quick guide:
ツナマヨ tuna mayonnaise
サルモン (or 鮭) salmon
明太子 spicy cod roe
鱈子 salted hake roe
チキンマヨ chicken mayonnaise
イクラ salmon roe
Vegetarian Onigiri :
野沢菜 pickled turnip
キムチ Korean spicy pickled cabbage (kimchi)
赤飯 azuki and black sesame rice
The rice can also be flavored with seaweed flakes, sesame oil, or dried bonito.
There are also more sophisticated onigiri which you can eat at restaurants, such as yaki onigiri, an onigiri covered with miso or soy sauce and then grilled so it's crispy on the outside. Some restaurants also serve ochazuke onigiri: onigiri served in a bowl of tea (or broth).
Onigiri can become true works of art in Japan, shaped into small characters made of rice and decorated with nori.