Nagaimo is one of those foods you see mostly in Asia and rarely in the Americas. Some people may experience itching when handling nagaimo due to an allergic reaction. If this happens lemon juice is used or diluted vinegar to help soothe any discomfort. You can also prevent itching by soaking nagaimo in vinegar water before cooking, but in this case we had it in sukiyaki wrapped in, wagyu or as I call it Nihon-gyu.