The division of Korea or the partition of Korea began at the end of World War II on 2 September 1945, with the establishment of a Soviet occupation zone in the north and a US occupation zone in the south. These zones developed into separate governments, named the Democratic People's Republic of Korea (North Korea) and the Republic of Korea (South Korea), which fought a war from 1950 to 1953. Since then the division has continued.
By the early 18th century, both countries were one single nation: the Korean Empire, only to be annexed by the Empire of Japan in 1910. During World War II, the Allied leaders had already been considering the question of Korea's future following Japan's eventual surrender in the war. The leaders reached an understanding that Korea would be removed from Japanese colonial control but would be placed under an international trusteeship until the Koreans would be deemed ready for self-rule. In the last days of the war, the United States proposed dividing the Korean peninsula into two occupation zones (a U.S. and Soviet one) with the 38th parallel as the dividing line. The Soviets accepted their proposal and agreed to divide Korea, which led to the declaration of General Order No. 1.
It was understood that this division was only a temporary arrangement until the trusteeship could be implemented. In December 1945, the Moscow Conference of Foreign Ministers resulted in an agreement on a five-year, four-power Korean trusteeship. However, with the onset of the Cold War and other factors both international and domestic, including Korean opposition to the trusteeship, negotiations between the United States and the Soviet Union over the next two years regarding the implementation of the trusteeship failed, thus effectively nullifying the only agreed-upon framework for the re-establishment of an independent and unified Korean state.
With this, the Korean question was referred to the United Nations. In 1948, after the UN failed to produce an outcome acceptable to the Soviet Union, UN-supervised elections were held in the US-occupied south only. Syngman Rhee won the election, while Kim Il Sung consolidated his position as the leader of Soviet-occupied northern Korea. This led to the establishment of the Republic of Korea in southern Korea on 15 August 1948, which promptly followed the establishment of the Democratic People's Republic of Korea in northern Korea on 9 September 1948. The United States supported the South, the Soviet Union supported the North, and each government claimed sovereignty over the whole Korean peninsula.
On 25 June 1950, North Korea invaded South Korea in an attempt to re-unify the peninsula under its communist rule. The subsequent Korean War, which lasted from 1950 to 1953, ended with a stalemate and has left Korea divided by the Korean Demilitarized Zone (DMZ) up to the present day.
When the Russo-Japanese War ended in 1905, Korea (then the Korean Empire) became a nominal protectorate of Japan and was formally annexed by Japan in 1910. Emperor Gojong was deposed. In the following decades, nationalist and radical groups emerged to struggle for independence. Divergent in their outlooks and approaches, these groups failed to come together in one national movement. The Korean Provisional Government (KPG) in-exile in the Republic of China failed to obtain widespread recognition until the onset of World War II.
At the Cairo Conference in November 1943, in the middle of World War II, Franklin D. Roosevelt, Winston Churchill and Chiang Kai-shek agreed that Japan should lose all the territories it had conquered by force. At the end of the conference, the three powers declared that they were "mindful of the enslavement of the people of Korea, ... determined that in due course Korea shall become free and independent." Roosevelt floated the idea of a trusteeship over Korea but did not obtain agreement from the other powers. Roosevelt raised the idea with Joseph Stalin at the Tehran Conference in November 1943 and the Yalta Conference in February 1945. Stalin did not disagree but advocated that the period of trusteeship be short.
At the Tehran and Yalta Conferences, Stalin promised to join his allies in the Pacific War in two to three months after victory in Europe. On 8 August 1945, two days after the first atomic bomb was dropped on Hiroshima, but before the second bomb was dropped at Nagasaki, the USSR declared war on Japan. As war began, the Commander-in-Chief of Soviet Forces in the Far East, Marshal Aleksandr Vasilevsky, called on Koreans to rise up against Japan, saying "a banner of liberty and independence is rising in Seoul".
Soviet troops advanced rapidly, and the U.S. government became anxious that they would occupy the whole of Korea. On 10 August 1945 two young officers – Dean Rusk and Charles Bonesteel – were assigned to define an American occupation zone. Working on extremely short notice and completely unprepared, they used a National Geographic map to decide on the 38th parallel as the dividing line. They chose it because it divided the country approximately in half but would place the capital Seoul under American control. No experts on Korea were consulted. The two men were unaware that forty years before, Japan and pre-revolutionary Russia had discussed sharing Korea along the same parallel. Rusk later stated that if he had known Korean history, he "almost surely" would have chosen a different line.
The division placed sixteen million Koreans in the American zone and nine million in the Soviet zone. Rusk observed, "even though it was further north than could be realistically reached by US forces, in the event of Soviet disagreement ... we felt it important to include the capital of Korea in the area of responsibility of American troops". He noted that he was "faced with the scarcity of US forces immediately available, and time and space factors, which would make it difficult to reach very far north, before Soviet troops could enter the area". To the surprise of the Americans, the Soviet Union immediately accepted the division. The agreement was incorporated into General Order No. 1 (approved on 17 August 1945) for the surrender of Japan.
Liberation, confusion, and conflict
On 10 August, Soviet forces entered northern Korea. Soviet forces began amphibious landings in Korea by 14 August and rapidly took over the northeast of the country, and on 16 August they landed at Wonsan. Japanese resistance was light, and Soviet forces secured most major cities in the north by 24 August (including Pyongyang, the second largest city in the Korean Peninsula after Seoul). Having fought Japan on Korean soil, the Soviet forces were well-received by Koreans.
Throughout August, there was a mix of celebration, confusion, and conflict, mainly caused by the lack of information provided to the Koreans by the Allies. The general public did not become aware of the division of Korea until around when the Soviets entered Pyongyang.
Meanwhile in Seoul, beginning in early to mid August, General Nobuyuki Abe, the last Japanese Governor-General of Chōsen (Korea), began contacting Koreans to offer them a leading role in the hand-over of power. He first offered the position to Song Jin-woo, the former head of The Dong-A Ilbo newspaper, who was seen as a champion of Korean independence within the peninsula. Song refused the position, which he saw as equivalent to the role of Wang Jingwei, the ruler of the Japanese puppet state in China. He instead preferred to wait until, as many expected and hoped, the KPG returned to the peninsula and established a fully domestic Korean government.
On 15 August, Abe instead offered the position to Lyuh Woon-hyung, who accepted it, to the chagrin of Song. That day, Lyuh announced to the public that Japan had accepted the terms of surrender laid out in the Potsdam Declaration, to the jubilation of the Koreans and the horror of the around 777,000 Japanese residents of the peninsula. With a budget of 20,000,000 yen from the colonial government, Lyuh set about organizing the Committee for the Preparation of Korean Independence (CPKI). The CPKI began taking over the security situation in the city and coordinating with local governments throughout the peninsula. However, the organization ended up being composed of mostly leftists, which infuriated Song even more. Lyuh attempted on multiple occasions to convince Song to join or support the CPKI, but their meetings reportedly ended in angry arguments each time.