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 1st Commonwealth Division and the 1st South Korean Division) seized the Jamestown Line destroying elements of the 42nd Army, 47th Army, 64th Army and 65th Army, and after five days of intense combat, eventually forcing the Chinese into retreat. The operation was a success, and ended on 15 October, with a few hills south of the line still in Communist hands, requiring a follow-up operation (Operation Polecharge). The official historian for the Korean War, Robert O'Neill, wrote of this battle: "In this action 3RAR had won one of the most impressive victories achieved by any Australian battalion. In five days