The geoduck (pronounced gooey-duck) is the world's largest burrowing clam — a saltwater bivalve of the northeast Pacific whose modest, permanently gaping shell, the size of a large fist, cannot begin to contain the enormous fleshy siphon that protrudes from it, a thick cream-and-tan neck that can stretch a metre or more. Buried deep in sand and mud from California to Alaska, with the great beds in Puget Sound and British Columbia, it is dug by hand and dredged by divers and prized above all in China, Korea and Japan, where the crisp, sweet, briny siphon is sliced paper-thin for sashimi or flashed through a hot pot. Sweet and intensely crunchy, far firmer than an oyster and cleaner than a typical clam, the geoduck is among the most expensive and sought-after shellfish in the Pacific trade.