Get a table knife ready. If you use a kitchen knife you may cut yourself.
Holding the clam firmly, insert the tip of the knife and sever the muscle holding the shell together. Cut the other side too.
The clam will open up a bit, so you can open it up to a point with your hands. Cut the muscles holding the shell halves together. There are 4 muscles, so press and slide the knife against them to remove them.
It will look like this when it's opened.
Take the insides out with your hands.
Put the shelled clams in a colander placed in a bowl, and rinse 3 times. *The clams will be de-sanded later on, so you only need to rinse them quickly at this stage.
Cut through the black part on the bottom in the photo - this is called the beak.
It will look like this. *There's a lot of sand in this part.
Slice in half horizontally.
It will look like this.
Retain a bit of the black guts as you rinse the clams. *This black part has a lot of flavor and umami, so I recommend that you don't take it all off.
Wash the clams one by one while rubbing them with your hands. Change the water at least 10 times as you wash them. The clams are ready when there is no more sand in the bowl.
The clams are now de-sanded and clean. You're done if you want to eat them as raw sashimi, or if you'll be using them in a cooked dish later on.
Turn this into blanched sashimi. Bring a lot of water to a boil and add a little salt. When the water is at a rolling boil, put the clams in for just 10 seconds to blanch them briefly!
Drain into a colander immediately. They will become a nice bright red color. Leave to cool off a bit.
Chill it in the refrigerator, slice up and they're done.
Story Behind this Recipe
I learned this from my father, who has been eating surf clam for years.
Wash the sand off very, very well!! Blanch the clam for just 10 seconds!! If you cook them for too long they will become tough, so watch out. Just blanch them briefly and they will become sweeter and tastier.