During World War II the island was strongly garrisoned by both the Imperial Japanese Army and Imperial Japanese Navy. The headquarters of the IJA 91st Infantry Division, responsible for defense of the northern Kurils, was established at Kashiwabara, and numerous coastal artillery positions and fortified bunkers were constructed in various locations around the island. In addition, the Imperial Japanese Army constructed four airfields: Kashiwabara Airfield in the northeast with Ki-43 Oscars, Kakumabestu Airfield on the southwest coast with a runway and Ki-44 Tojos, Kitanodai Airfield on the northeast coast with a runway, and Suribachi Airfield, an auxiliary base in the center of the south coast with two runways. The Imperial Japanese Navy had Musashi Airfield on the south-western tip of the island with two runways, one and another , operating a variety of aircraft as well as a radar site. These bases were subject to sporadic air raids from the US Army Air Forces and US Navy based in the Aleutian Islands from 1943 until the end of the war.