Yes, potatoes are a New World vegetable, kinda like the tomato. But just as Italians have been using tomatoes in their cuisine for hundreds of years, white potatoes have had ages to be authentically incorporated into East Asian cuisines.
"I first heard of potatoes being eaten in China from a plant explorer who was in Western China and watched the local workers eat PLAIN (no soy sauce, nada) roasted potatoes for lunch/dinner," says opinionatedchef. "Since then, I have eaten a super-duper popular Korean noodle dish, jajangmyun—homemade noodles topped with a black bean sauce with chopped pork, potatoes, onions, and zucchini—that often contains cubes of potato."
"Shredded potatoes stir-fried with hot peppers is in several Sichuan restaurants in the U.S.—and I saw potatoes in several guises in the Sichuan province," adds Steve. "Isn't China the largest potato producer in the world?"
"Potatoes are also used in miso soup (there was a recent Facebook survey on this topic on FB Japan), and you can't rule out potato salad, which is a standard teishoku-ya and homestyle dish," says E Eto. "In Japan, potatoes are pretty much a staple ingredient in the pantry. I've also had steamed potatoes (preferably recently harvested) served either with a miso sauce, or butter-soy sauce (a Hokkaido standard)."
kerosundae's favorite is potatoes roasted over charcoal: "When charcoal or rocks are done burning, mostly grey on the outside but still red inside, bury potatoes in the charcoal or rocks and cook for the next hour or 2, kind of the same way as pachamanca. There is absolutely no other way to get potatoes to taste like that. This is not a part of modern home cooking, since nobody has access to a fire pit in their apartment; when people lived in houses with the stove as a part of the bed, people made this all the time."