Nagaimo and its wild mountain cousin, yamaimo, have slightly different tastes, textures, and shapes, but they are both cut up and grilled or eaten raw in the same way. The raw nagaimo is grated into a sticky cream called Tororo. To add flavour, Tororo can be put on rice, soba, or udon noodles or mixed with dashi (fish stock). When raw nagaimo touches some people’s skin, it can cause a mild reaction.
This can make the lips feel like they are tingling. Other tubers, like taro or cassava, must be cooked before they can be eaten.