TUNA SAKU is a frozensushi grade yellowfin tuna, and is commonly used as maguro in sushi bars. It is boneless, skinless, frozen vacuum packed yellowfin tuna that has been cold smoked (processed with filtered wood smoke) to keep its red color. These blocks are perfect for making raw-fish delicacies, such as: Sashimi: Slices of raw fish. Poke: Hawaiian raw fish salad. Tataki: Lightly seared raw tuna.