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Beniimo (Purple yam)


Photo: KANO Tatsuhiko

Beniimo is a type of sweet potato that is popular in Okinawa, even though there is no species of potato that bears the name. Beniimos are actually varieties of purple yams called Miyanou-36 and Bise.

Miyanou-36 is said to have been brought by a sweet potato dealer to Yomitan village in the middle of Okinawa island. The potato was well suited to the village’s soil and became a popular breed among farmers. They were soon sold as Yomitan Beniimo. Yet even though the soil was ideal, growing beniimo was a challenging endeavor as they were constantly affected by vermin. And while the farmers went through much hardship, the market preferred good looking potatoes grown in mainland Japan. As a result, beniimo were sold mainly for traders and manufacturers, who purchased them directly from the farmers. In addition, it was difficult to promote the potato because, when eaten on its own, it was less sweet than regular sweet potatoes.

Okinawan beniimo became popular thanks to a local confectionery company in Yomitan called “Porsche.” The company, which has the motto of making confectionery rooted in the community, sold a pastry using beniimo at festivals and received a positive response. They decided to commercialize the pastry, which soon became quite popular and led other manufacturers to follow them and start making beniimo confectionery.

The greatest appeal of beniimo is its color, a vivid purple born from nature. The moderate level of sweetness, once considered a defect, became one of its appeals as healthy eating became more important to many people. Beniimo are now welcomed as an ingredient that is not too sweet. Beniimo confectionery includes tarts, yokan (bean paste jelly) and cream puffs, which are popular products in many Okinawan bakeries and confectionery shops. It has also become one of the most popular souvenirs for tourists. Purple Sweet Potato Cereal (85 yen), made from beniimo and sold by Muji1, makes both a great breakfast and nibbles to accompany drinks. 

Beniimo is also called murasakiimo (purple potato) and murasaki satsumaimo (purple sweet potato). As I mentioned earlier, there is no species named beniimo and its color is actually not beni (crimson red), but purple. The Okinawans who combined beni, a color often associated with something noble, with the unpretentious and ordinary imo, must have had great foresight. I got excited at the prospect of the vernacular term beniimo having great meaning for Okinawans. But then my friend mumbled, “But the festival in Yomitan is called Murasaki Festival, not Beni,” which was kind of a letdown. Thinking about how sweet potatoes began to be called satsumaimo in Japan2, I always pray for the beniimo name to live on every time I eat a beniimo tart.

Editor’s Note:

  1. As of 2023, the product is no longer available.
  2. Satsumaimo is simply called nmu (imo). Sweet potato was first introduced to Okinawa then brought to the Satsuma Domain (present-day Kagoshima prefecture). The imo was renamed as satsumaimo and distributed to other parts of Japan.