In 1609, Satsuma, at the southern tip of Kyūshū, conquered Okinawa (then called the Ryūkyū Kingdom). Throughout the subsequent Tokugawa period, Satsuma was said to have kept the Ryūkyūans in a state of virtual slavery by plundering the profits of the lucrative Sino-Ryūkyūan trade and imposing an excessively heavy tribute-tax on the native products. This exploitation of Ryūkyū's trade and native resources was reported to have been one of the important financial resources for Satsuma; and one that made possible Satsuma's vigorous political and military activities in the middle nineteenth century leading to the Meiji Restoration of 1868. In spite of such claims, no study of this topic has been made except those that have been strongly colored by the sympathies of the writer.