The snack supposedly originated in
Omaezaki City in what today is
Shizuoka Prefecture. Around 1824 a merchant named Shozo Kuribayashi began in manufacturing this dish on a small scale. In 1892, Rinzo Ohniwa and Jinhichi Inagaki of modified the manufacturing process to facilitate industrial production. Soon this product spread throughout Japan as a popular type of preserved food. It was also used during the
Russo-Japanese War, briefly gaining the sobriquet as "soldier's potatoes." In 1908 large scale production began in
Ibaraki prefecture. Two theories exist about how this product was introduced to Ibaraki prefecture. One theory holds that a rice cracker maker named Toshichi Yuasa hired a technician who modified his dried seafood processing facility to produce this agricultural product. Another theory holds that Seiji Koike and Jizan Ouchi got the backing of the governor of Ibaraki Prefecture, Masataka Mori, to start up local production with the aid of two technicians from Shizuoka. Both public and private sectors in Ibaraki Prefecture have promoted steamed dried sweet potatoes extensively. In 2019 the
Hitachinaka Chamber of Commerce and Industry was selected by the Japan Chamber of Commerce and Industry as the winner of a commerce prize for its "Dried Sweet Potato Attraction Project" that included the development of
hoshiimo cakes and a book outlining the history of dried sweet potatoes. Today over 80% of the steamed dried sweet potatoes sold in Japan are from Ibaraki prefecture. == Nutrition ==