Nemuro Subprefecture
Rasshua was inhabited by the Ainu, at the time of European contact, and the remains of over 40 dwellings have been discovered. The island appears on an official map showing the territories of Matsumae Domain, a feudal domain of Edo period Japan dated 1644, and these holdings were officially confirmed by the Tokugawa shogunate in 1715. Subsequently, claimed by the Empire of Russia, sovereignty initially passed to Russia under the terms of the Treaty of Shimoda, but was returned to the Empire of Japan per the Treaty of Saint Petersburg along with the rest of the Kuril islands. At this time, the remaining Ainu inhabitants (eight families) were forcibly relocated to Shikotan, and the island became uninhabited. The island was formerly administered as part of Shimushiru District of Nemuro Subprefecture of Hokkaidō.