先島群島
Archaeological studies in the Sakishima Islands in southern Okinawa Prefecture are not so active as those in the main Okinawa Islands. Some Okinawa-led archaeological reports labeled some sites in Miyako and Yaeyama as "gusuku-like." Archaeologist Ono Masatoshi raised concern about the naïve application of the Okinawan gusuku-as-fortifications framework and urged that scholars should not turn a blind eye to the diversified nature of archaeological sites with stone walls in these islands. Few gusuku sites can be attributed to the fact that the Sakishima Islands were over a hundred years behind Okinawa socially and technologically. In 1500, Ryukyu invaded and annexed the islands, which would have limited further local gusuku development. The primary gusuku site in Yaeyama is Furusutobaru Castle, residence of Oyake Akahachi, which was attacked by Nakasone Toyomiya of Miyako shortly before the invasion by Ryukyu.