Operation Chromite was the UN assault designed to force the North Korea People's Army (NKPA) to retreat from the Republic of (South) Korea. On 25 June 1950 the NKPA invaded South Korea, launching the first major armed conflict of the Cold War.
Post-WWII defense cutbacks weakened U.S. armed forces, but U.S. response to the invasion across the 38th parallel dividing North and South Korea was supported by UN allies. Although the efforts of the U.S. Eighth Army and Republic of Korea (ROK) troops in central South Korea slowed but could not stop the invading force, a defensive perimeter did hold around the port of Pusan. General of the Army Douglas A. MacArthur, the U.S. Commander in Chief, Far East, and Commander in Chief, United Nations Command (CINCUNC), persuaded his superiors in Washington to approve his plan for an amphibious assault at Inchon, a major port 110 miles behind enemy lines on South Korea's west coast; the landing would force the NKPA to withdraw or risk destruction. MacArthur's plan was to advance from Inchon to capture the nearby air base at Kimpo, and then liberate the NKPA-occupied South Korean capital of Seoul, which was also the key link in the North Korea logisitical support network.
The success of MacArthur's plan was reliant on a strong and coordinated sea, air, and land force. The Inchon invasion demonstrated how naval forces can be a decisive factor in littoral operations. The 230 ships of Vice Admiral Arthur D. Struble's Joint Task Force (JTF) 7, with the aid of Royal Navy and other Allied warships, established superiority in the Yellow Sea as well as the air over it. The continued presence of U.S. and Allied naval forces acted as a deterrent to Soviet and/or Chinese intervention. The element of surprise was essential to Operation Chromite.
On 13 September 1950, the naval forces in JTF 7 led by Admirals Struble and James H. Doyle, began their attack against Inchon. Carrier-based aircraft squadrons, destroyers, and cruisers battered North Korea's fortifications, coastal artillery batteries, and supply points for two days. On 15 September, 1st Marine Division assaulted three beaches and quickly seized Inchon. General MacArthur signaled that "the Navy and Marines... never shone more brightly" than at Inchon.
By 19 September, the Marines had captured Kimpo air base, into which flowed Marine close support aircraft and U.S. Air Force supply transports. U.S. Army troops advanced from the beachhead and linked up with their comrades advancing north from the Pusan perimeter. Marine, Army, and South Korean troops captured Seoul on 28 September 1950.
During the first seven days of Operation Chromite, the joint task force counted approximately 70 killed, 470 wounded, and five missing. The toll rose to 600 killed, 2,750 wounded, and 65 missing during the fight to liberate Seoul. UN forces killed 14,000 North Korean soldiers and captured 7,000.