What are Okinawan Sweet Potatoes?

Mary McMahon
Mary McMahon

Okinawan sweet potatoes, sometimes called Japanese purple potatoes, or Japanese sweet potatoes, are a unique variety of sweet potato which is actually native to the Americas, not Japan, let alone Okinawa. These sweet potatoes have become famous and very distinctive because of their richly colored flesh, which happens to be a vibrant purple, in a marked contrast to the dull tan skins of this produce item. Okinawan sweet potatoes can be used in a wide assortment of dishes, and they are especially popular in Japan and Hawaii.

Okinawan sweet potatoes are especially popular in Japan and Hawaii.
Okinawan sweet potatoes are especially popular in Japan and Hawaii.

Before we delve into the specifics of the Okinawan sweet potato, we should briefly discuss the great sweet potato vs yam debate, which has been raging ever since potatoes were first brought to Europe. Yams are tubers from the genus Dioscorea, and they are native to Africa. Sweet potatoes are in the genus Ipomoea, and they are native to the New World. They are also not related to potatoes, which are in a separate plant genus, Solanum.

Okinawan sweet potatoes are purple cousins of the well-known orange sweet potato.
Okinawan sweet potatoes are purple cousins of the well-known orange sweet potato.

Confused yet? The issue with yams, sweet potatoes, and potatoes began when sweet potatoes were first brought to Europe, and called potatoes. When true potatoes entered Europe, Europeans realized that they were entirely different plants, and they created a retronym, “sweet potato” to describe the plants they previously called potatoes. The trend of referring to some sweet potatoes as “yams” emerged in the American South, where growers started referring to soft-fleshed sweet potatoes as yams to differentiate them from the firmer, less sweet varieties grown in the North.

Now that we've dealt with that problem, let's talk about Okinawan sweet potatoes, which made their way to China from the New World at some point between 1492 and 1605, when they were first brought over to Japan. The Japanese realized that this tuber could make a very useful crop, as it is extremely hardy and well equipped to deal with the sometimes mercurial weather in Japan. The Okinawan sweet potato quickly entered popular Japanese cuisine, where it is used in tempura, mashed and served with a variety of foods, and even integrated into pastries. You may see them called tamai kuru or beni imo in Japan.

Like many other aspects of Japanese cuisine, Okinawan sweet potatoes came to Hawaii, where they are a cornerstone of Hawaiian cuisine. Food historians claim that this is not because of the astounding purple color, but rather because these tubers are flavorful, creamy, and high in fiber, vitamin C, and antioxidants. From Hawaii, they have entered the mainland United States, where they are primarily consumed as a novelty food, especially in the case of sweet potato pie, which looks quite lurid when prepared with Okinawan sweet potatoes.

Okinawan sweet potatoes are popular throughout Japan.
Okinawan sweet potatoes are popular throughout Japan.
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


These are great. However, I find I break out it vicious hives if I'm not careful as to cook them long enough.

If I they are cooked thoroughly, not problems whatsoever.


Taro or Kalo has oxalic acid, which, if you don't properly cook the root or leaves long enough can cause an itchy throat. It is usually not an allergy but just not cooked long enough. People can be allergic to any kind of protein.

Sweet potatoes are not related to taro so it should not be causing the same problem. We usually do not eat sweet potato or their leaves raw.


They talk about the Okinawan sweet potato being introduced in Hawai'i, which it was. However, Polynesians, including Hawaiians, have had over 40 varieties and colors of sweet potato for hundreds of years before outside contact. Where did they get them? The DNA has been tested and they originally came from Peru. Yes, Polynesians were voyaging around the Pacific long before Columbus landed in the Americas.


Sweet potatoes can be an allergen. So it's possible.


I love this veggie! So easy to cook (just bake in the oven, wrapped in aluminum if you want even cooking) and makes a great snack/breakfast. Sweet and filling!


Ditto to the first poster.

Okinawa only became part of Japan in 1879, when the Ryūkyū Kingdom was formally annexed by Japan and turned into the Okinawa Prefecture of Japan. Roughly in the same era that the Kingdom of Hawaii was overthrown and annexed by the USA (1894 - 1898).


Actually, I fed my nine month old baby purple potatoes. He broke out in hives. I used it in a vegetable soup. He's not had any allergies to any other veggies, but when I added the purple potatoes, he broke out for three days until I suspected the potato.


Seeking info on the Okinawa sweet potato which has a light skin, thin purple corona under the skin, and a light golden interior.


To the person with the strange reaction, now I have no idea if Taro is related to the Okinawa Potato, but I have heard some people say taro root has given their tongue and throat a strange reaction. I think it happens mostly with the tTaro leaves though and only when they were underdone and not cooked well enough.

It is possible you're allergic to it, people can have reactions to just about anything. My friend has a son who is literally allergic to his own sweat. Or it could be something you put on the potato or cooked with it, or maybe it's possible there was a pesticide used on it that you're having a reaction to.

Who knows, allergies are strange like that. Obviously, until you're sure just don't eat it again.


To the person whose tongue and throat was numb - must have been something else that caused the numbness - not the potato.


I have had a strange reaction to eating the Okinawan Purple Sweet Potato. I had a numbness of my tongue and throat. Has anyone else had this type of reaction?


Okinawa was not a part of Japan when the sweet potato was brought from China to Okinawa. Okinawa was invaded by the Satsuma Clan in 1609. -CTaira

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