[1] Shumshu was inhabited by the Ainu, who subsisted off of the abundant fish, marine mammals and birdlife in the area, at the time of European contact.

In 1875, sovereignty over the Kuril Islands, including Shumshu, was transferred to the Empire of Japan per the Treaty of Saint Petersburg.

As the island closest to Russia, it became an important Japanese military outpost, as well as a center for the commercial fishing industry.

All coastal areas suitable for enemy amphibious landings were covered with permanent emplacements and bunkers, interconnected with underground passages and trenches.

Kataoka Naval Base was under the command of the IJN′s 5th Fleet and had three 60-foot (18.3 m) oil storage tanks as well as barracks and supply buildings.

These facilities were subject to sporadic air raids by United States Army Air Forces and United States Navy forces based in the Aleutian Islands from 1943 until the Japanese Emperor Hirohito announced the surrender of Japan on 15 August 1945.

Combat operations continued through 23 August 1945, ending with the surrender of the surviving members of the Japanese garrison.