Sakishima Islands
The kingdom extended its authority over the southernmost islands in the Ryukyu archipelago by the end of the 15th century, and by 1571 the Amami Ōshima Islands, to the north near Kyūshū, were incorporated into the kingdom as well. While the kingdom's political system was adopted and the authority of Shuri recognized, in the Amami Ōshima Islands, the kingdom's authority over the Sakishima Islands to the south remained for centuries at the level of a tributary-suzerain relationship.