Dioscorea japonica, known as East Asian mountain yam, yamaimo, or Japanese mountain yam, is a type of yam (Dioscorea) native to Japan (including Ryukyu and Bonin Islands), Korea, China, Taiwan, and Assam.
Dioscorea japonica is used for food. Jinenjo, also called the wild yam, is a related variety of Japanese yam that is used as an ingredient in soba noodles.
In Japanese, it is known as . is another kind of Dioscorea japonica, which is native to fields and mountains in Japan.
In Chinese, Dioscorea japonica is known as yàshÃÂnyào () which translates to English as "wild Chinese yam" or simply "wild yam". Another name is RìbÃÂn shÃÂyù (; literally "Japanese yam").
In Korean, it is known as cham ma (), as well as dang ma ().
Dioscorea japonica contains the antimutagenic compounds eudesmol and paeonol.
Several formal botanical varieties have been proposed. Four are accepted:
In Japanese cuisine, both the Japanese yam and the introduced Chinese yam are used interchangeably in dishes and recipes.
The yam's aerial tubercles, or bulbils, called mukago, are also eaten. They are often cooked and served with white rice.