Near the end of the Second World War in July 1945, Sasaki was recalled to active duty, and was appointed commander of the newly-formed 149th Division, based in Manchuria. The division never saw combat during the Soviet invasion of the region and was disarmed on 23 August, after which Sasaki was taken prisoner by the Soviet Army. He was handed over to the Chinese communist authorities in July 1950, who interned him at the Fushun War Criminals Management Centre in Liaoning Province. He died there of a cerebral haemorrhage on 30 May 1955.