To make saku cubes, tuna is first filleted. The fillets are then cut into blocks. After which the blocks are cut into smaller "rolls" Saku. Sakubrolen are used in Japanese cuisine to prepare sushi and sashimi. chutoro means "medium softness" because of the abundant fat content. Chu can be found in the outer part of the loins, close to the skin. chutoro is characterized by a pink color and its rudeness. High quality chutoro is a mix of the red skinny and the fatter area. Saku chutoro is without bone and ready for preparation. Saku chutoro is freshly available. High quality is also available frozen when frozen at -60.