A line used to divide the occupation of Korea became a division between two rival governments. Both wanted to rule the whole country.
Korea had been a Japanese colony, governed by Japan rather than by an independent Korean government. Japan's defeat ended that rule in 1945. Soviet troops accepted the Japanese surrender in the north and American troops in the south. Their occupation zones met at the 38th parallel, an east-west line of latitude at 38 degrees north of the equator. This partition, or division, was an occupation arrangement, not a permanent national border agreed by Koreans. As relations between the USA and Soviet Union (USSR) worsened, agreement on one government became harder.
In 1948, Syngman Rhee led the anti-communist Republic of Korea in the south, while Kim Il Sung led the communist Democratic People's Republic of Korea in the north. Both claimed the right to rule all Korea and wanted reunification: bringing the country under one government, their own. Border fighting, suppression of opponents and internal conflict deepened hostility. These tensions help explain the background, but they did not make a major invasion inevitable. North Korea launched the invasion that began full-scale war on 25 June 1950.
Worked example: What made war possible, and what started it?
Distinguish a long-running problem from the decision that began full-scale war.
- Division left two governments claiming the same country. Neither accepted rule over only its own part as a final solution.
- Border clashes made the rivalry more violent, but an ambition to reunify Korea was not yet the same as a large invasion.
- Kim's decision to send the North's army into the South on 25 June 1950 turned that unresolved rivalry into full-scale war.
Watch out for this
The two Koreas had always existed as separate countries.
Korea's postwar division developed from the occupation zones in 1945 and the rival governments established in 1948. The line did not settle either government's claim to rule the whole country.
Check your understanding
Which explanation separates the background to war from its immediate outbreak?
- The rival claims to reunify Korea meant that full-scale war had already begun when the governments formed in 1948.
- Partition created rival claims; the North's invasion on 25 June 1950 turned the conflict into full-scale war.
- The occupation line settled the political dispute, so the 1950 invasion had no connection to earlier rivalry.