Masu (trout) sushi is made with rainbow trout, which ascends streams from the sea for egg laying. Since the Edo Period, this sushi has been handed down as part of the local cuisine culture in the Jinzu River area.
There is a variety of sushi such as “Nigiri-zushi” (vinegar rice topped with sliced raw or cooked fish), Chirashi-zushi (vinegar rice bed with a layer of raw fish and vegetables) and Maki-zushi (rolled sushi). Masu sushi falls into the category of Oshi-zushi (pressed sushi). While, in pressed sushi making, many pieces are usually pressed in one mold, Masu sushi is made piece by piece with a round wooden mold about 20cm in diameter. Onto vinegar rice laid in the mold, slices of rainbow trout are put and a lid is placed to press. To keep its quality, vinegar rice and trout are wrapped with bamboo leaves, which add a clean appearance and fresh smell to sushi.
Masu sushi is popular as a lunch sold at train stations and as a food gift. There are many sushi shops specializing in trout sushi mainly along the Jinzu River. As a food gift for overseas, vacuum-packed Masu no sushi is recommended.