Onigiri, she says, has mass appeal because it’s simple to make, is gluten-free and is versatile. And other Japanese foods like ramen and sushi have found worldwide popularity, she notes.

Dishes like the ingredient-topped donburi and the world-famous sushi are easy to delineate. However, preparations like nigiri ...

Starting on Jan. 27, the prices of onigiri rice balls at the stores will jump by up to 28 yen (18 cents), while the cost of bento lunch boxes and sushi will rise by as much as 60 yen beginning on Feb.