Soak the orient clams in salted water to remove the sand.
Boil the water and sake in a pot and then add the clams. Steam until the shells open.
Once they open, stop the heat and season with the butter and pepper. Serve on a dish and garnish with finely chopped green onion.
Story Behind this Recipe
A long time ago, an izakaya (pub) that I used to go to had "clams steamed in sake" and "clams with butter" on the menu.
Other than the natural salt and flavor from the clams, you don't need anything else. You can also make this with manila clams. But orient clams are larger and have better texture, so I usually buy them instead.