Surf Clam
Food turns out differently, depending on the cooking methods we use. The surf clam is a good example. What a magical effect temperature can have on food! When surf clams are raw (including alive), the color of its foot (the tip side) is grayish-brown or light-brown, but when it is heated (eg,. boiled or steamed), the same part becomes pinky-red. Like crabs and shrimp, surf clams are said to have “astaxanthin” (a kind of “carotenoid”), which is combined with a certain kind of protein when they are alive. But when they are heated, “astaxanthin” separates from the protein. Because “astaxanthin” is the pigment which (when alone) gives red color to animals and plants, the color of surf clam turns to reddish when they are boiled.

As its Japanese name indicate (lit. “north side clam”), the habitat of the surf clam is off the Pacific coast from Ibaraki to Hokkaido Prefecture. Those who live in the Tokyo area (including me), seldom come across the shells of surf clams when we walk around nearby beaches. But when I visited the coast of Ibaraki Prefecture, there were many shells of a certain  kind of bivalve here and there. They looked unusual to me; they were larger and thicker than the size of hamaguri-clam shell (common oriental clam). The shells were surf clams’, and interestingly, there were more of them than any other type; I gathered a lot of them in a short time!

I once heard that this shellfish was quite popular in the areas alongside of the west coast of Tohoku and Hokkaido regions. After seeing and gathering so many of their shells on that beach, I could understand their popularity. Local supermarkets offer living surf clams as a matter of course. People there have developed many dishes using the shellfish, for example, rice boiled with surf clam, surf clam curry with rice, and sushi topped with surf clam boiled or raw.

The shells were also a plaything for the Ainu children (Ainu is indigenous people in Hokkaido Prefecture). They made a kind of high-clogs by boring a hole at the highest part of the shells, threading a long rope through two shells, and knotting both of the ends at the back of the shells. The surf clam shell is; about 10cm long, triangular in shape; it is round, thick, and hard. It seems to fit comfortably under the arch of the children’s feet, and is strong enough to support their weight. It must have been fun to walk, or run with them on.

Raw or boiled? This is the choice now you have when you order surf clam sushi. But I think that boiled surf clam used to be more popular, or there used to be only one choice - boiled form - for surf clam when used as a topping for sushi in the Tokyo area. My mother, who grew up in Yokohama, still can’t get used to raw surf clam. When surf clams are served boiled, their feet and bodies are picked up and cut into half horizontally, and then boiled. The color of their tip side turns pinky-red and their root side remains ivory-white. As a result, the color of the boiled surf clam is beautifully graduated; pinky-red, pale-pink, and ivory-white. When you eat it, you will immediately notice, a sweet, rich, delicious taste; the texture is chewy, since it was boiled. As a whole, boiled surf clam makes a sophisticated impression compared to raw surf clam which I will introduce in the next paragraph.

The appearance of the raw surf clam is plane; partly grayish-brown and partly light-brown; its base color is ivory-white. It looks less attractive than the boiled surf clam. However, raw surf clams can be served in different ways; feet, bodies, mantles, and adductor muscles. This is because it has to be served very fresh, so they are served as soon as they are removed from the shell. Sushi chefs might want their customers to enjoy many different parts which can be eaten when (while?) they are very fresh. It is INTENSELY tasty and sweet, and has very strong aroma of the ocean. The tastiness comes from amino acids, such as taurine, alanine, and glycine, which are said to be very plentiful in surf clam.