From the time corresponding to the Jomon ( to 200 BC) and Yayoi (200 BC to 250 AD) periods to the Late Heian period (897-1185 AD) on the mainland of Japan, the islands of the Ryukyu chain developed an independent culture and history with qualities distinctive from the Japanese.
From the 12th to the 15th centuries, the islands entered the Gusuku (Castle) era and the Ryukyus became a unified cultural sphere with the creation of the Ryukyu Kingdom. The background to these developments was the tremendous changes carried out in the East Asian region surrounding Okinawa.
During the 14th century, China assumed a central role in East Asia and a new order within the region was established. Adjacent countries, including Japan, began trading relationships. Many ships traveled in and out of Okinawa via the close-by East China Sea. The Ryukyu chain of islands became a place where merchants came and went as they pursued their trading.