Bluefin tuna is one of the most highly prized fish used in Japanese raw fish dishes. About 80% of the caught Atlantic and Pacific bluefin tunas are consumed in Japan. The fish is renowned for fetching high bids at the first auction of the year in Tokyo's Tsukiji Market. The world’s most expensive fish is the 222-kilogram bluefin tuna that sold for $1.8 Million (155.4 million yen) in January 2017.
In this video, a large tuna is separated into sections of differing grades and prepared into a delicious sushi meal.
Japanese began eating tuna sushi in the 1840s, when a large catch came into Edo [old Tokyo] one season. A chef marinated a few pieces in soy sauce and served it as nigiri sushi. At that time, these fish were nicknamed shibi — "four days" — because chefs would bury them for four days to mellow their bloody taste.