Japan Sushi
Salmon nigiri
Nigiri pairs hand-formed rice with a topping. The name does not tell you every detail of the fish or its preparation.
Ask about Salmon nigiri
One shape of sushi
What the name usually describes
The Japan National Tourism Organization describes sushi as vinegared rice paired with a topping, and nigirizushi as a hand-shaped mound of that rice with the topping draped over it. The topping can be seafood, egg or vegetables — sushi does not automatically mean raw fish.
Salmon is this note's own example; a topping name says little about the cut, the source or how the fish was handled.
A fast food with older roots
Japan's Ministry of Agriculture, Forestry and Fisheries traces nigiri-zushi back to earlier preserved and fermented forms of fish and rice, and describes how the hand-shaped version became popular as a stall food in Edo-period Tokyo.
In other words, the small piece on the plate is a relatively quick descendant of a much slower tradition.
How it is commonly eaten
JNTO notes that sushi appears across a wide range of settings in Japan, from conveyor-belt restaurants to formal counters, and describes dipping the topping — not the rice — into soy sauce. Japan's agriculture ministry describes the topping shaped into a bite-sized piece over vinegared rice and served with wasabi or a dipping sauce.
Which species, cut and treatment the topping gets is a shop-by-shop decision. The plate in front of you decides the details.
Ask how this serving was prepared
Sushi toppings can be served raw or cooked. A picture and a dish name cannot reliably establish which treatment was used for this piece, or the species and source of the fish.
If preparation, ingredients or allergens matter to you, check with the person who made or served it.