Korean reunification selected the 38th parallel as a dividing line. Japanese troops to the North of this line were to surrender to the Soviet Union and troops to the South of this line would surrender to the United States. This was not originally intended to result in a long-lasting partition, but Cold War politics resulted in the establishment of two separate governments in the two zones in 1948 and rising tensions prevented cooperation. The desire of many Koreans for a peaceful unification was dashed when the Korean War broke out in 1950. In June 1950, troops from North Korea invaded South Korea.
Australia in the Korean War where they became the first UN air unit to enter the war, primarily in ground support, combat air patrol, and escort missions. 3 RAR was rapidly committed as Australia's main land force contribution to the United Nations forces in the Korean War. After a period of intensive training and reinforcement in Japan, the battalion arrived in South Korea in late September 1950. The battalion formed part of the 27th Commonwealth Brigade and took part in the United Nations offensive into North Korea and the subsequent retreat into South Korea following the Chinese offensive in the winter of 1950–51. It was