Nagaimo (長芋) is a type of mountain yams. It’s long and has light color skin and hairy roots. It can be eaten raw unlike other types of yams.
To eat, we peel the skin with a peeler (or knife). Nagaimo is very slippery, so be careful. You may experience itch when you touch it with bare hands (but you won’t feel it when you eat it). To prevent from turning color to reddish-brown, you can add a few drops of vinegar. As a quick appetizer, we cut nagaimo into matchbox sticks and pour soy sauce to enjoy (I put nori on top too).
Grated nagaimo is called tororo and it’s very gooey and slimy. We pour tororo over the rice and enjoy it with soy sauce and raw egg. We also serve tororo on soba noodles to make Tororo Soba. I usually use nagaimo to make Okonomiyaki. Grated nagaimo has lots of air in it and when you cook with it, the food gets fluffy and airy, perfect for Okonomiyaki.
You can find Nagaimo in produce section of Japanese or Asian grocery stores.