Otoro nigiri sushi is a traditional type of nigiri sushi. It consists of hand-pressed sushi rice that's topped with slices of fatty cuts of tuna. Different cuts of tuna are classified as otoro (fatty), chutoro (medium-fatty), and akami (red meat).
The dish has a rich flavor and a melt-in-the-mouth texture that makes it quite expensive. Traditionally, this type of sushi is eaten by hand in a single bite. It's usually accompanied by soy sauce, wasabi, or pickled ginger (gari) on the side.