Pouches of abura-age (fried tofu) boiled in a sweet sauce stuffed with seasoned rice. いなりずし。
In folklore, the Fox Deity loves abura-age, therefore these sushi are called "Inari" or "Fox Deity." (You will find this deity's most famous shrine in Fushimi in Kyoto). The rice is usually plain sushi rice, but can also be another type of seasoned rice. The result is simple, but surprisingly moist and hearty. Inarizushi were first made in the middle of the 19th c.
[Inarizushi. Photo Ad Blankestijn]
Inarizushi are not available in a sushi shop, but plentiful in supermarkets and convenience stores. They are also often a side dish in soba and udon restaurants. Inarizushi are also easy to make at home - you can buy the abura-age pouches in the supermarket.
Inarizushi are good as a snack in-between meals, but also easy to combine with other foods. They help the appetite and are easy to digest.