O-nigiri, also known as o-musubi, nigirimeshi or rice ball, is a Japanese food made from white rice formed into triangular or cylinder shapes and often wrapped in nori (seaweed). Traditionally, an onigiri is filled with pickled ume (umeboshi), salted salmon, katsuobushi, kombu, tarako, or any other salty or sour ingredient as a natural preservative. Because of the popularity of onigiri in Japan, most convenience stores stock their onigiri with various fillings and flavors. There are even specialized shops which only sell onigiri to take out. Due to its popularity in Japan, the trend of small restaurants and convenience stores selling onigiri has traveled to other parts of the world.
Ao Onigiri started as a mobile rice ball shop. The owner rode with a nostalgic bicycle-pulled trolley on the back and went around the city. His impressive appearance and, of course, delicious rice balls very soon became known and finally he opened a shop in November 2012. They make rice balls on order. There are about 20 different fillings inside from typical ones, such as grilled salty salmon and grilled cod roe to unique ones like dried squid pieces flavored with spicy Korean paste and sesame oil. The rice cooked in an iron pot is plain but very tasty. A rice ball is from 130 yen. If you order more than 3 pieces, the staff will wrap them with a bamboo leaf.