East China Sea

West of the Ryukyu Islands, the East China Sea separates the island arc from the Asian mainland. Passages between the islands connect it with the Philippine Sea, while the Okinawa Trough runs along the chain's western side.

From 1372, Ryukyuan rulers sent tribute missions across these waters to Ming China. Ryukyuan ships also carried goods between China, Japan, Korea and ports in Southeast Asia. In 1609 forces from the Japanese domain of Satsuma invaded the kingdom; Ryukyu subsequently remained linked to China while subject to Satsuma's authority.