Okinawa Island
In the Sanzan Period (1322–1429), or Three Kingdom period, numerous gusuku, or castles were built across Okinawa Island. The area of present-day Uruma fell under the control of the Chūzan Kingdom, which covered the central area of Okinawa Island and its nearby islands. The Katsuren area of Uruma became notably prosperous in the mid-15th century. Katsuren Castle, and a surrounding jōkamachi castle town, were constructed in this period.