おにぎり is rice triangle! Very simple and very tasty. Get everywhere in convenience store.
You can choose if you want 玄米 or 白米.
Plain salty onigiri
Japanese apricot / plum
Tuna with Mayonaise
kombu with salt
seaweed boiled in soy sauce
Brassica juncea var. integrifolia
walleye pollack roe
There is a legendary shop in Otsuka you should not miss if you are into Onigiri.