The Okinawan sweet potato is mainly grown in Hawaii where it was first introduced in the 17th century. It is not well-known on the mainland but some are grown in California. They can be found in specialty markets on the West Coast. It is also known as Tumai Kuru or Beni Imo.
The Okinawan sweet potato is often confused with another sweet potato that has red skin and a deep purple flesh, which is grown on Molokai. The Okinawan is also often mistaken for the Filipino purple yam, ube, which actually has a closer resemblance to the sweet potato grown on Molokai that has deep purple flesh.
When selecting, choose those that are firm and small to medium in size, avoiding those that have shriveled skins, soft spots, or blemishes. They should have a fresh smell and not be musty. Select potatoes that are similar in size to provide for even cooking. They should be stored in a cool, dark, dry place and used as soon as possible after purchasing. In warm weather climates, such as in Hawaii, the potatoes will sprout quickly so it may be necessary to refrigerate them, but do not refrigerate for more than five days.