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 to as the Fifth Phase Offensive, with the intention of recapturing Seoul. The Chinese launched a major assault between 22 and 25 April that resulted in a victory in the Battle of the Imjin River. At the same time, the UN repelled Chinese forces at Kapyong. Chinese forces of the 118th Division attacked the Kapyong Valley in force, and pushed South Korean and New Zealand troops into retreat. Under heavy pressure, the Korean 6th Division broke, and the line collapsed. American and South Korean men poured through a gap under protective covering fire from Australians who were holding their section