Dioscorea japonica

Dioscorea japonica (yamaimo, Japanese mountain yam) is a type of yam (Dioscorea) native to Japan (including Ryukyu and Bonin Islands), Korea, China (including Taiwan), and Assam.

Dioscorea japonica is used for food. Jinenjo, also called wild yam is related variety of Japanese yam that is used as an ingredient in soba noodles.