The "89th division" was assigned to the 5th area army 27 March 1945. The 3rd mixed brigade and headquarters were staying on the Iturup island, while parts of 4th mixed brigade part was garrisoning Shikotan island. Also, one battalion of the 4th mixed brigade was deployed on Kunashir Island. The "89th division" has relied on heavy fortifications of Minami Chishima Fortress. After the Soviet Invasion of the Kuril Islands has started 18 August 1945, the Shikotan was invaded 1 September 1945, while Iturup garrison have surrendered 4 September 1945 without resistance, as the hostilities ceased 2 September 1945.