Gusuku period

The Gusuku period is an era of the history of the Ryukyu Islands corresponding to the spread of sedentary agriculture from Japan and the construction of gusuku, large stone structures resembling castles. Directly following the Shellmidden period, the Gusuku is generally described as beginning in the 11th century, following a dramatic social and economic shift over the previous centuries. The Shellmidden-Gusuku transition has been linked alternatively to migrants from Kyushu, possibly Hayato refugees, or to Yamato influence from the Dazaifu trade outpost at Kikaijima. Such developments may have also led to the emergence of the Proto-Ryukyuan language.

The period saw extensive agriculture in the archipelago, including the cultivation of foxtail millet, rice, barley, and wheat. Widespread trade occurred with China and Japan, both with the imports of foreign ceramics and the export of the local Kamuiyaki ware. A unique vernacular architecture emerged in the region, featuring elevated village houses. Initially defended by palisades, the rise of the local aji nobility steadily led to the expansion of fortifications, eventually leading to the construction of the namesake gusuku, massive limestone fortresses which proliferated across Okinawa and Amami. Increasing consolidations of aji holdings led to the tripartite division of Okinawa into the Sanzan lordships. Following the First Shō dynasty's hegemony over the island in the early 15th century, Shō Shin formed the centralized Ryukyu Kingdom and destroyed the power of the local aji, ending the Gusuku period.