Beniimo (sometimes spelled benimo, beni-imo; sometimes referred to as ube) is a variety of sweet potato with a distinctive purple color. Sweet in taste, the potato is an integral part of Okinawan diet and culture, with its history on the island dating back more than 400 years.

Before the introduction of beniimo in 1605, famine commonly swept through villages on Okinawa. The island’s crops were subjected to a variety of natural torments ranging from the torrents of rain and extreme winds of typhoons to periods of intense draught. One bad storm or a few weeks without rain frequently caused extensive crop failure and starvation of citizens.

Enter Noguni Soukan, a Ryukyuan trading official stationed for a time in the Fukien province of China. Interested in botany, he often passed time learning about Chinese agriculture and experimenting with the plants in his garden. When he happened upon the hardy sweet potato around the turn of the century, he quickly realized that the tuber’s hardy nature would be quite suitable for Okinawa. It grew well in rocky, unnourished soil as well as in marshy, un-drained soil, so no matter what Mother Nature brought to the island nation, the potato would survive.

In 1605, Noguni Soukan returned to Okinawa with his purple potato, and with the help of Gima Shinjo (a higher ranking official eager to improve agricultural development), word of this vegetable of salvation spread. By 1620, the beniimo (known then as to-imo, or Chinese potato) was grown throughout Okinawa, saving hundreds from starvation annually. It later spread to mainland Japan, where it became known as the Satsuma potato.)

During times of agricultural or economic strife, the easily-grown beniimo has always come to the rescue. Some of Okinawa’s older residents well remember bringing a sweet potato to school every day to each for lunch, particularly during the years following World War II.

Recognizing the economic and agricultural impact of the introduction of the beniimo, Kadena Town celebrates Noguni Soukan (whose real name is unknown—Soukan was the title he earned as a Ryukyuan minister, and Noguni was his hometown, located near present-day Kadena) and his contribution each year with a festival. His tomb, located in Kadena Town, is designated a Prefectural Cultural Asset, and there is a statue of him not far from Kadena Marina. Citizens affectionately refer to him as Umu-ufushu, or “Sir Sweet Potato.”

Today, beniimo are integrated into dozens of foods on Okinawa. Not only can they can be cooked, boiled, and mashed in the same way as Russet or Irish potatoes, but they are also commonly found on Okinawa in desserts such as tarts and ice cream and are even sliced into chips and baked or fried. Many prize the purple tubers for their nutritional value, as they are high in antioxidants and vitamins.

In villages across Okinawa, but particularly in Yomitan, are unattended roadside stands that contain loose beniimo. These stands operate on an honor system in which customers take the number of beniimo needed and leave the appropriate payment. Such stands are an icon of everyday, rural Okinawa.