Satto

Satto (察度) (c. 1320 – 1395), also known as Chadu, was a king of Chūzan, one of three kingdoms formerly on the island of Okinawa. His reign was marked by expansion and development of Chūzan's trade relations with other states, and the beginning of Okinawa's tributary relations with Ming Dynasty China, a relationship that continued for roughly five hundred years, almost until the fall of the Qing Dynasty.

Satto was Governor of the Urasoe district, which surrounded and included Chūzan's capital. On the death of King Seii in 1350, Satto seized the throne for himself. His own line, or dynasty, however, did not last past his son, Bunei, who was ousted in 1405.

Chinese envoys arrived in Chūzan in 1372, requesting admission of Chinese cultural supremacy and that Okinawa send representatives to Nanjing. Satto complied with these requests without hesitation, as this granted him formal license to trade with the most powerful nation in the region. He sent his younger brother Taiki (泰期) to Nanjing in 1374, as the leader of a mission to formally submit to China, entering into tributary and trade relations. The Hongwu Emperor entertained the Ryukyuan mission, accepted their gifts, and sent them back with various gifts from China, including a royal seal, which served as a symbol of investiture. A Chinese official accompanied the returning mission, and represented the Imperial Court in officially confirming Satto as king of Okinawa. Though Okinawa was never conquered or annexed by China, this custom of investiture, of formally confirming the king in the eyes of the Chinese court, continued as part of tributary relations until the dismantling of the Ryūkyū Kingdom five centuries later. There were at least nine tributary missions to China over the next twenty years, three of them led by Taiki.