How different is Military Demarcation Line (MDL) from 38th Parallel?

Many foreigners, including some young Koreans, get confused about the Military Demarcation Line and the 38th Parallel. After World War II, instead of Japan, Korea became divided like Germany, a casualty of the Cold War dynamics. When Japan surrendered, the U.S. and the Soviet Union entered Korea to disarm Japanese forces in Korea. They agreed to divide Korea temporarily along the 38th Parallel: the north under Soviet control and the south under American control.

This division was not caused by Korea's direct involvement in World War II, but it set the stage for future conflict. Five years later, in 1950, North Korean communists invaded free and democratic South Korea, starting the Korean War. This war lasted three long years and ended in 1953 with an armistice, not a peace treaty, which resulted in the creation of the Military Demarcation Line, or MDL. This line differs from the 38th Parallel, as it reflects the front lines at the war's ceasefire.

The armistice talks began in July 1951 due to a stalemate in the war and lasted two full years, with 158 meetings in total. Finally, in July 1953, an agreement was signed. As part of the armistice, both sides agreed to establish a Demilitarized Zone (DMZ), a buffer zone extending 2 kilometers on each side from the MDL, to reduce the risk of further military clashes.

This historical backdrop helps explain why Korea remains divided today, with the DMZ marking a significant and unique boundary on the Korean Peninsula.

Advanced Learning FAQ for Those Interested in Korean War History

Q: Why did the Soviet Union accept the U.S. proposal to stop at the 38th Parallel after already taking over North Korea?
A: At the time, the Soviet Union had to consider the military power of the United States, especially since the U.S. possessed nuclear weapons. Additionally, the Soviets needed American cooperation to secure their interests in Manchuria and to regain the four northern islands taken by Japan during the Russo-Japanese War in 1904. To maintain a good relationship with the U.S., it is believed that the Soviets accepted the proposal with no conditions.

Q: Why is the Military Demarcation Line (MDL) not a straight line?
A: On July 27, 1953, both sides signed the armistice at 10:00 a.m., with the ceasefire taking effect at 10:00 p.m. that same day. The MDL was determined based on the positions held by both sides on July 24, three days before signing. Markers were placed every 200 meters to establish the line clearly. The MDL stretches approximately 240 kilometers (155 miles) from the Imjin River to the East Sea.

Q: Why did it take two years to reach a ceasefire agreement?
A: While the MDL issue was resolved relatively quickly, the main sticking point was the repatriation of prisoners of war (POW). The enemy delegation was largely influenced by the Chinese leadership, and about 70% of the 20,000 Chinese POWs refused to return to China. This situation embarrassed Chinese leader Mao Zedong, turning a military issue into a political one and delaying a resolution.

Q: Why does the current MDL extend further north on the east and further south on the west compared to the 38th Parallel?
A: During the two-year stalemate, South Korean forces were primarily responsible for the eastern front and sought to reclaim as much territory as possible, leading intense battles for strategic positions. Meanwhile, on the western front, operations were limited by declaring a neutral zone around the peace talks site near Gaesong and later Panmunjom (JSA). This, combined with the exhaustion of UN forces due to Chinese offensives, resulted in a focus on defense rather than aggressive advance, preventing the full reclamation of territory south of the 38th Parallel before the war.✔️