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Incheon Landing (Operation Chromite)
September 15, 1950· Battle· Wars & invasions
Well documentedSolid records, physical evidence or scientific consensus.
A risky US-led amphibious landing behind North Korean lines at Incheon, west of Seoul, that reversed the early course of the Korean War.
See it on the Korean History map →What happened
With UN forces penned inside the Busan Perimeter, General Douglas MacArthur landed about 75,000 troops of X Corps at Incheon (인천상륙작전) on September 15, 1950. His own planners objected: tides of about 10 m gave ships only short windows, and mudflats and seawalls guarded the port. Marines took Wolmido island in the morning, landed in the evening against light defenses, and held the city by the next day. Seoul was retaken on September 28, cutting the North Korean army's supply lines.
Why it matters
It turned near-defeat into a rout of the North Korean army within two weeks, and its success tempted the UN to push north.
How we know
US Army and Marine Corps official histories, UN Command and South Korean records, and Soviet documents showing the panic in Pyongyang that followed.
Still debated
Whether it was genius or a lucky gamble against thin defenses is still argued, as is why Pyongyang ignored reported Chinese warnings of a landing.
Connections (3)
▸Battle of the Busan Perimeter held until Incheon Landing (Operation Chromite)Well documented
The connection
By holding the pocket around Busan, UN and South Korean troops pinned most of North Korea's army in the far south, at the end of long, exposed supply lines. That made a landing far behind the front at Incheon worthwhile; on September 16 the Eighth Army broke out, linking up with the landing force near Osan ten days later.
When and how
Southeast Korea and Incheon, August–September 1950; Walton Walker's Eighth Army held the line while MacArthur's X Corps landed on September 15.
How we know
US Army official histories and operational orders document the timed breakout and the link-up of the two forces.
Debates and open questions
Whether pulling a Marine brigade off the perimeter for Incheon put the line at risk, and whether the breakout could have succeeded without the landing.
▸Incheon Landing (Operation Chromite) turned the tide of Korean WarWell documented
The connection
The landing cut the main roads and railways feeding North Korean troops in the south. Within two weeks Seoul was retaken, the North Korean army collapsed as a fighting force, and tens of thousands of its soldiers were captured. The war swung from near-defeat for the South to a UN advance into the North.
When and how
Incheon and Seoul, September 15–28, 1950; MacArthur's X Corps, built around the US 1st Marine and 7th Infantry Divisions, with South Korean Marines.
How we know
Battle records on both sides, and Soviet archives showing Kim Il-sung's urgent appeals to Stalin and Mao for help in late September 1950.
Debates and open questions
Whether the decisive blow was the landing itself or the weeks of attrition along the Busan Perimeter that had already exhausted the North Korean army.
▸Incheon Landing (Operation Chromite) drew UN troops north, prompting Chinese entry into the Korean WarWell documented
The connection
Victory emboldened Washington and MacArthur to go beyond restoring the 38th parallel and aim at unifying Korea. South Korean troops crossed on October 1 and US troops on October 7; Pyongyang fell on October 19. As UN forces neared the Yalu, Mao, who had warned China would intervene, sent troops across.
When and how
October 1950; Zhou Enlai's warning through India's ambassador, K. M. Panikkar, on October 3; Mao's decision after Politburo debate; first crossings on October 19.
How we know
Chinese and Soviet documents released in the 1990s tie China's decision closely to UN troops crossing the parallel.
Debates and open questions
China had begun massing troops on the border in July 1950, so it may have intervened anyway. Would stopping at Korea's narrow 'waist' have kept it out?