Tuna is one of the most popular fish among both Japanese and non-Japanese people. At sushi bars, some chefs are not happy on the days when the tuna is not good—even if all of the other fish they are serving up that day are good quality. Of course, the opposite is also true. My point here is: Sourcing good tuna is imperative for success in your sushi adventure. But not all tuna are created the same.