Why Korea was divided

G3 Elective History - syllabus K336, 2027

What this lesson teaches

  • I can weigh up why the Korean War and the Vietnam War broke out, and what followed each war.

    Syllabus K336, The Cold War, Learning Outcomes. Assess the reasons for the outbreak of the Korean War and the Vietnam War, and their aftermath.

Make a guess

In 1945 Soviet and US troops split Korea at the 38th parallel to take Japan's surrender. What do you think that line was meant to be?

  1. A temporary line for the occupation, not a lasting border.
  2. The old border between two Korean kingdoms, restored after Japan left.
  3. A permanent border agreed by Koreans in a vote.
Show the answer

A temporary line for the occupation, not a lasting border.

It only divided the two zones. As the superpowers fell out, it hardened into the border between two rival states formed in 1948.

A line drawn in 1945 to split the occupation of Korea became the border between two rival governments, each wanting the whole country.

Japan ruled Korea as a colony until its defeat in 1945. Soviet troops then took Japan's surrender in the north, and US troops in the south. Their zones met at the 38th parallel, a line of latitude. This was meant for the occupation, not as a lasting border. As the USA and USSR fell out, agreeing on one Korean government became harder.

In 1948, two states formed. Syngman Rhee led the anti-communist Republic of Korea in the south. Kim Il Sung led the communist Democratic People's Republic of Korea in the north. Each claimed the whole country and wanted to reunite it under its own rule.

Border fights and harsh rule deepened hatred. But war was not certain. North Korea chose to invade the South on 25 June 1950.

38th parallel
Line dividing the Soviet and US zones in 1945.
1948
Rhee leads the South; Kim Il Sung leads the North.
25 June 1950
North Korea invades the South.

Worked example: What made war possible, and what started it?

Separate a long-running problem from the decision that began the war.

  1. Background: two governments each claim all of Korea.
  2. Rising tension: border clashes make the rivalry violent.
  3. Trigger: Kim sends his army south on 25 June 1950.

Watch out for this

The two Koreas had always been separate countries.

Korea was one country, ruled by Japan until 1945. It was split only after the war.

Check your understanding

Why was Korea divided at the 38th parallel?

  1. It was the historic border between two Korean kingdoms long before Japanese rule.
  2. Koreans voted in 1945 to create two countries with different political systems.
  3. It split the Soviet and US zones for taking Japan's surrender in 1945.
Show the answer

It split the Soviet and US zones for taking Japan's surrender in 1945.

Yes. It was an occupation line that became a lasting division.

Sources and context

Background reading for this chapter.

  • Truman Library: statement of 27 June 1950

    Paraphrase of President Truman's public statement of 27 June 1950, held by the Truman Library.

  • FRUS: Zhou statement, December 1950

    Paraphrase of Chinese foreign minister Zhou Enlai's statement of 22 December 1950, transmitted to the UN on 23 December and reproduced in a US diplomatic telegram of 24 December.

  • National Archives: Korean Armistice Agreement

    Paraphrase of the Korean Armistice Agreement, 27 July 1953, preamble and Article I, held by the US National Archives.

  • Truman Library: statement of 27 June 1950

    An original cartoon drawn for these notes in the style of an American newspaper cartoon published in July 1950, soon after the UN Security Council asked member states to help South Korea. It is not a copy of a real cartoon.

  • Truman announces American action, 27 June 1950

    Extract from President Truman's public statement on the situation in Korea, 27 June 1950, two days after North Korea invaded. A US government document in the public domain; text from the American Presidency Project.

  • the UN Security Council resolution, 27 June 1950

    Extract from United Nations Security Council Resolution 83 (1950), adopted on 27 June 1950 by 7 votes to 1 (Yugoslavia), while the Soviet representative was boycotting the Council. A UN record.

  • China's warning, October 1950

    Extract from a circular telegram from the US Acting Secretary of State to US diplomatic posts, 5 October 1950, two days before American forces crossed the 38th parallel. Foreign Relations of the United States, 1950, volume VII, document 614. A US government document in the public domain. (Abbreviations as in the original.)

  • MacArthur advises Truman, 15 October 1950

    Extract from the record of the meeting between President Truman and General MacArthur at Wake Island, 15 October 1950, compiled by General Omar Bradley from notes kept by the officials from Washington. Top Secret. Foreign Relations of the United States, 1950, volume VII, document 680. A US government document in the public domain.

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