Ōsato

The Ōsato house took its name from Ōzato, a district and castle in southern Okinawa. Its best-remembered ruler appeared in Chinese records as Shōsatto, likely the same name as the place. Ryukyu tradition made the family descendants of a son of King Eiso of Chūzan, enfeoffed as aji of Shimasoe-Ōzato.

After 1314 Tamagusuku failed to hold his lords together, and the Lord of Ōzato withdrew south and founded Nanzan, the smallest of the Sanzan realms. Shōsatto sent his first tributary mission to the Ming court in 1380 and was invested as King of Nanzan with a gilded silver seal in 1385.

In 1392 the Sashiki aji Shō Hashi stormed Shimasoe-Ōzato and the court moved to Shimajiri-Ōzato. Four years later a coalition led by Shōsatto's uncle Ōeishi overthrew him; Nanzan passed to rival lines until Shō Hashi annexed it in 1429.