Tori-gai, Japanese Cockle

If your sushi chef gives you a small bicolored clam—half white and half velvety, dark purple—this is tori-gai, “bird clam.” It is said that tori-gai is so named because its foot resembles the beak or legs of a bird, tori, but you may need to use your imagination to concede this. When I see tori-gai sitting on top of a nigiri-zushi rice ball, the clam’s shape and colors remind me of a black bird with a long white tail stretching down from the top of the rice ball.

The tori-gai sold in Japan for sushi is already shucked from its grooved shell, which resembles that of the akagai. We choose clams with meat that is thick, firm, and resilient and an intense purple color—all qualities that indicate freshness. The clam is blanched before it is used for sushi, and this brightens the purple color. You must handle tori-gai delicately to avoid rubbing away the color.