Onigiri( rice ball ) is a Japanese food “WASHOKU” that flavored boiled rice or put the ingredient into it and is the shape of a triangle, box-shape and the shape that is spherical by pressure molding.
Onigiri is a size of the grade which is generally in a palm.
Onigiri is good at portability and storage stability. Therefore, Onigiri is appreciated as portable food and box lunch from the distant past until the present in Japan.
Now, Onigiri is sold at the convenience store etc. and is becoming in use as staple food.