THE 38th parallel in question is a circle of latitude 38 degrees north of the equatorial plane. This line divides the Korean peninsula roughly in half (leaving about 56% of Korean territory on the northern side). The actual border between North and South Korea slants across this circle of latitude, finishing some distance north of it on the east coast. Nonetheless people often loosely refer to the border between the two Koreas as the “38th parallel”. Why has the name stuck?
As Japan neared defeat in the second world war, the Allies had to decide what to do with its colonies, including Korea. They had discussed running it jointly as a trusteeship, but without specifying the zones of occupation. Japan’s swift collapse in August 1945 lent new urgency to their deliberations. A possible dividing line was proposed by Colonels Charles Bonesteel and Dean Rusk during an all-night meeting on August 10th. They wanted the American zone to extend far enough north to include Seoul. But it also had to remain acceptable to the Soviet Union, which landed troops on Korea long before the Americans arrived. Bonesteel first thought the line should defer to provincial boundaries, but did not have a map of the provinces to hand. Instead he chose the 38th parallel. To Rusk’s surprise the Soviets accepted.
This dividing line was breached on June 25th 1950 when North Korea invaded the south. An armistice was not signed until July 27th 1953. In the first year of the war, the momentum of battle ebbed and flowed dramatically. But the 38th parallel remained a significant reference point throughout. It was named in the original United Nations resolution calling on the North Koreans to withdraw. It was also important to Mao Zedong, who entered the war to devastating effect when the UN forces ventured north of it. By June 1951, the UN forces had regained the upper hand, driving the Chinese back beyond the 38th parallel. But America’s political leaders were wary of pushing far beyond it lest they lose the support of their UN allies, draw the Soviet Union into the fray or provoke China to redouble its efforts. The Americans turned a deaf ear to the South Korean President, Syngman Rhee, who had long insisted on the reunification of his country. One of his colonels referred to the 38th parallel as “that damned line”.
After two more years of attritional warfare and stop-start negotiations, the two sides agreed to turn the frontline, as it stood, into a “military demarcation line” separating the two Koreas, with a so-called “demilitarised zone” extending two kilometres on either side. That is where the de facto border remains. It reflects where the warring parties stood when the fighting stopped not some arbitrary circle of latitude. And yet it would be hard to argue that the eventual border’s proximity to the 38th parallel was a coincidence. The two sides were willing to stop fighting because they felt the status quo had been restored. And that feeling reflected their proximity to that “damned line”.