Chūtoro Tuna

Chūtoro is a part of bluefin tuna that refers to medium fatty cuts when served as a part of nigiri or sashimi. The tuna yields otoro (fatty parts from the belly), akami (red meat), and chūtoro, which is a combination of both that's found near the skin on the back and belly.

It's a mix of otoro's sweetness and a deep, slightly bitter flavor of akami. This part of bluefin tuna is usually a bit more on the expensive side, and it's typically served on special occasions or festivities. Specifically, the part of the back near the head is called sekami, the center of the back is senaka, and the part near the tail is called seshimo.