【Reading】いわがき

【English Name】Rock oyster

The iwagaki (rock oyster) is a large bivalve living along the coasts of Japan, belonging to the family Ostreidae like the magaki (Pacific oyster). Widely distributed from southern Hokkaido to Kyushu, it inhabits rocky-reef zones deeper than the intertidal zone to depths around 20 m. It does not form large colonies the way the magaki does.

Its greatest feature is that its season is summer. While the magaki fills out in winter, the iwagaki reaches the peak of its flavor from early to midsummer and is prized as the "summer oyster." The shell is brown and thick, and the flesh inside is large and creamy. Rich umami and sweetness, plus a slight astringency and bitterness, create depth.

At sushi restaurants it is often served raw, and the standard is to enjoy the material's own flavor with lemon or ponzu. When made into nigiri sushi, the large flesh is cut and portioned. It is also sometimes made into gunkan-maki.

Major production areas are centered on the Sea of Japan side, such as the Oki Islands of Shimane Prefecture, Mie, Akita, and Ishikawa. In addition to wild gathering, aquaculture is also active, and it is rich in nutrients such as glycogen and zinc.