The sushi roll containing crab, avocado, and cucumber is called the California roll. It is a North American style of sushi, commonly made with imitation crab or crab salad, avocado, and cucumber.
California rolls are usually prepared as uramaki, or inside-out rolls, with the rice on the outside and nori seaweed surrounding the filling. Sesame seeds, tobiko, or masago may be added to the rice. The inside-out format helped appeal to diners who were unfamiliar with, or reluctant to eat, seaweed on the outside.
The roll's invention is disputed. Accounts credit Los Angeles chefs Ken Seusa and Ichiro Mashita, while Vancouver chef Hidekazu Tojo has also claimed responsibility. Early versions may have used real cooked king crab rather than imitation crab, and recipes evolved over time. The name first appeared in print in 1979, and the roll helped popularize sushi across the United States during the 1980s.