The Japanese Sweet Potato and the Japanese Yamaimo (Mountain Yam) are often confused as being the same potato however, they are two different tubers. The light tan outer skin color of Yamaimo is similar to a baking potato and differs in appearance from the reddish-pink skin coloring of the Japanese Sweet. The Japanese Yamaimo is a somewhat sticky, mountain yam which is the variety often used to make soba noodles.