The Okinawa Trough, lying to the East of China, is a back-arc basin formed by extension within continental lithosphere behind the Ryukyu trench-arc system. Middle to late Miocene uplift, associated with normal faulting of the initially adjacent Ryukyu non volcanic arc and the Taiwan-Sinzi folded belt, corresponds to the first rifting phase. The timing of rifting is supported by the presence of marine sediments of corresponding age drilled in the northern Okinawa Trough. The rifting occurred after a major early Miocene change in the motion of the Philippine plate with respect to Eurasia and ceased during the Pliocene.