Nagaimo is one of my favorite Japanese vegetables and with the perpetual popularity of Japanese cuisine, nagaimo continues to gain more visibility in the West. It is a Japanese yam that, unlike other yams which can only be eaten cooked, can be eaten either cooked or raw. Nagaimo is also known as Chinese yam, Korean yam, Japanese mountain yam or is sometimes referred to as yamaimo.
There is some confusion between the two Japanese terms yamaimo and nagaimo, which are actually two distinct species of yam although the two names are often used interchangeably at grocery stores and in recipes. To further add to the confusion of the proper terminology for this Japanese vegetable, in Japanese, this yam is occasionally referred to as tororo, although this usually refers to the yam after it is grated, and when it is in its liquid and mucilaginous state.
To some, nagaimo is not the most attractive looking yam, yet it is one of my favorite Japanese vegetables, along with okra. Nagaimo has a light beige exterior that is pockmarked with dark spots and long hairs. The outer skin is easily removed using a vegetable peeler prior to preparation, exposing a white and slimy yam. It has a crisp and firm, yet slimy texture when eaten as is.
One of the most popular ways of preparing nagaimo is to grate it. The yam is quite starchy and has a flavor that is bland and very light. For this reason, grated nagaimo is often served in dishes with flavors that are bold, such as with a soup, for example, tororo soba (thin buckwheat noodles) or udon (thick wheat noodles). It is also served grated and with a soy sauce based dashi broth, which actually helps to bring out the unique flavors of the otherwise bland nagaimo. Other ways in which nagaimo is prepared is fried, as in tempura, sautéed, or as an ingredient in temaki sushi (hand-rolled sushi), or grated and incorporated into a variety of dishes.
The simplest way to enjoy the crisp and fresh flavors of nagaimo is raw, sliced, and in a chilled Japanese salad simply garnished with soy sauce. While a ponzu citrus soy sauce may also be used, the bold savory flavor of the soy sauce really brings out the umami of this nagaimo salad. The salad may be garnished with dried bonito flakes (katsuobushi), daikon sprouts (kaiware) or fragrant green perilla leaves (ao shiso).
1 small piece nagaimo (roughly 3 to 4 inches in length)
Dried bonito flakes, for garnish, optional
To Garnish:Daikon sprouts, kaiware, thinly sliced green perilla leaves, or shiso,optional
Gather the ingredients.
Using a vegetable peeler, remove the outer skin of the nagaimo, exposing the white inner flesh of the root. Due to its mucilaginous texture, the yam is very slippery and might be difficult to handle.
Slice the nagaimo lengthwise into thin and small rectangular pieces. Serve in small individual appetizer plates and chill in the refrigerator until ready to serve.
Just before serving, garnish with dried bonito flakes (katsuobushi) and optional daikon sprouts (kaiware), shiso, or other optional garnishes. Serve with a drizzle of soy sauce or seasoned soy sauce (dashi shoyu).