September 15, 1950

Battle of Inchon

UN forces land at Inchon in Operation Chromite

Inchon's water level could change by roughly thirty feet, forcing the assault into two narrow high-tide windows nearly twelve hours apart.

6:33 a.m. on Green Beach

After air strikes, naval gunfire and rocket barrages, the first Marine assault wave reached Green Beach on Wolmi-do at 6:33 a.m. on 15 September 1950. The 3rd Battalion, 5th Marines rapidly took the island, which commands Inchon harbor.

That first wave came ashore in 17 LCVPs, with nine tanks carried in three LSVs. Holding Wolmi-do was what made the main landings possible at the evening high tide.

Then the Marines on the island waited while the tide drained the harbor into mudflats.

Scaling ladders against the seawalls

At roughly 5:32 to 5:33 p.m., the main Marine forces landed at Red and Blue Beaches, climbing the seawalls with scaling ladders and fighting North Korean defenders in trenches and bunkers.

A Republic of Korea Marine battalion joined the U.S. Marines at Red Beach — the first amphibious operation conducted jointly by the two marine corps. Reporters had nicknamed the enormous supposedly secret buildup "Operation Common Knowledge."

D-day cost the Marines 20 killed, 174 wounded and one missing.

What the beachhead was, and what it was not

By early on 16 September the assault force had taken its D-day objectives and held an uncontested beachhead. MacArthur directed the operation from aboard USS Mount McKinley; Edward Almond commanded X Corps ashore and Oliver P. Smith the 1st Marine Division.

The often-quoted figure of nearly 70,000 personnel describes the operation and its subsequent echelons, not the number who stepped ashore on 15 September; the supporting naval force was 230 ships drawn from seven navies.

The landing did not itself recapture Seoul. Fighting for the capital continued until late September.

Sources

Researched 24 Aug 2026 7 sources not yet audited

How this was checked

Researched from the web into a fact sheet and rewritten from that sheet. This article has not yet had an independent model audit. How the pipeline works →

What the sources leave uncertain

The September 15 landing date is secure. Sources use Inchon, Inch’on, and the modern spelling Incheon for the same place.
The operation’s endpoint varies by definition: official sources distinguish the September 15 landing, the seizure of the immediate beachhead, and the longer Inchon-Seoul campaign.