Hamachi Saku Block is a premium sashimi-grade cut of Japanese yellowtail (Seriola quinqueradiata), also known as buri or Japanese amberjack, portioned into a rectangular block ("saku") ready for slicing. Sold fresh from the Costco Service Deli, this fish is prized in Japanese cuisine for its naturally high fat content, which gives it a rich, buttery mouthfeel, a delicate crisp bite, and a mildly sweet, ocean-fresh flavor.

The saku block format is the standard preparation used by professional sushi chefs and home cooks alike. Slices cut across the grain yield beautiful sashimi pieces or nigiri toppings. The fish can also be served as carpaccio, briefly seared for a tataki preparation, or incorporated into poke bowls and crudo dishes.