Partition and raids
Occupation, two states, Jeju 3 April (1948), and a militarised parallel before the conventional war.
Milestones in order. This is history, not a weekly activity grid.
- Division at the 38th
- Two republics
- Invasion
- Pusan Perimeter
- Inchon
- China enters
- Seoul lost and retaken
- Talks begin
- ROK resistance to armistice
- Armistice signed
Darker cells mean a higher score for this topic on that metric.
Scale62
Intensity78
Duration72
Tech shift55
Political impact80
Cultural memory70
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Last reviewed Sources & creditsMedia creditsMethodology
Quick answers
Are the scores a ranking of nations or armies?
No. Scores are browsing aids inside an era-bounded atlas — not live league tables of countries.
How many people died?
Korean civilian deaths are often estimated at about 2-3 million. ROK military deaths are about 137,000; DPRK military deaths are less certain. US deaths are about 36,000. Chinese deaths are cited in a wide scholarly range, often 180,000-400,000. All figures are ranges, not precise censuses.
Why did the United Nations intervene?
The US took the war to the Security Council. Resolutions 83 and 84 (June-July 1950) recommended members assist the ROK. The Soviet Union was boycotting the Council over China's seat, so it did not veto. Sixteen countries sent combat forces; others sent medical units.
What was Inchon?
A surprise amphibious landing on 15 September 1950 at a port with extreme tides, designed to cut KPA supply lines to the Pusan Perimeter. It succeeded operationally and led to Seoul's recapture. It did not end the war, because the UN then drove north and China entered.
Why did China enter?
As UN forces approached the Yalu and the DPRK neared collapse, Mao's government -- after debate -- sent the People's Volunteer Army from mid-October 1950. Chinese accounts stress defending the border and supporting a socialist ally; UN accounts stress surprise and winter retreats from the north.
Who were the main commanders?
MacArthur (until relieved 11 April 1951), then Ridgway and Clark for the UN; Rhee and ROK chiefs including Chung Il-kwon and Paik Sun-yup; Kim Il-sung and Choi Yong-kun in the north; Peng Dehuai for Chinese forces. Truman's relief of MacArthur is a central civil-military episode.
Any honest history starts in 1945, not only at dawn on 25 June 1950: occupation, two constitutions, and a militarised parallel.
The war's three campaigns -- south, north, then stalemate -- are easier to teach than the two-year negotiation that killed men for outposts while the text of an armistice was haggled.
Timeline
- Division at the 38th
US and Soviet occupiers choose the 38th parallel as a temporary line. Japanese rule ends; two military governments begin.
- Two republics
ROK (15 August) and DPRK (9 September) are proclaimed. Separate armies and ideologies replace occupation improvisation.
- Invasion
KPA crosses the parallel. Seoul falls in days. UNSC Resolution 83 follows on 27 June.
- Pusan Perimeter
Eighth Army and ROK hold a southeastern corner. August is the existential month of the ROK.
- Inchon
Operation Chromite lands at Inchon; Seoul is retaken on 28 September; KPA retreats north in disorder.
- China enters
PVA forces clash with UN troops in late October; the full shock hits in November. The UN retreats from the Yalu in winter.
- Seoul lost and retaken
Chinese/NK offensive takes Seoul again; Ridgway's counteroffensives restore a line near the parallel by spring.
- Talks begin
Armistice negotiations open at Kaesong, later Panmunjom. Fighting continues on ridges while diplomats argue POWs.
- ROK resistance to armistice
Rhee releases anti-communist POWs to complicate a deal; the US negotiates side assurances and a defense treaty.
- Armistice signed
Clark (UNC), Nam Il (DPRK), and Peng's deputy sign. Guns largely fall silent. No Korean peace treaty follows.
Eras
Invasion and perimeter
KPA southward rush; Taejon; the stand at Pusan.
Inchon to the Yalu
Chromite, Seoul, the UN crossing north, and the approach to China's border.
Chinese war and restabilisation
Chongchon, Chosin/Jangjin, the retreat, Ridgway's restoration, Seoul's last recapture.
Talks and ridges
Kaesong/Panmunjom, air war, outpost battles, and the July 1953 signature.
Milestones
UN Command precedent
The first large armed enforcement under the UN flag -- legally unique because of the Soviet boycott.
Chinese intervention
The PVA's entry made clear that a unified Korea under UN/ROK arms would mean war with the PRC.
Armistice without treaty
A ceasefire that became a seventy-year political system.
The signature at Panmunjom stopped a movement war and started a border system. It did not restore 1945's "temporary" line as a mere administrative convenience.
South Korean truth commissions since the 1990s have documented wartime civilian massacres on the southern side as well as northern and US air-war harm -- a fuller ledger than 1950s pamphlets.