The Battle of Okinawa, codenamed Operation Iceberg, was a major battle of the Pacific War fought on the island of Okinawa by United States Army and United States Marine Corps forces against the Imperial Japanese Army. The initial invasion of Okinawa on 1 April 1945, was the largest amphibious assault in the Pacific Theater of World War II. The Kerama Islands surrounding Okinawa were preemptively captured on 26 March, by the 77th Infantry Division. The 98-day battle lasted from 26 March until 2 July 1945. After a long campaign of island hopping, the Allies were planning to use Kadena Air Base on the large island of Okinawa as a base for Operation Downfall, the planned invasion of the Japanese home islands, 340 mi away.
The United States created the Tenth Army, a cross-branch force consisting of the US Army 7th, 27th, 77th and 96th Infantry Divisions with the USMC 1st, 2nd, and 6th Marine Divisions, to fight on the island. The Tenth was unique in that it had its own Tactical Air Force, and was also supported by combined naval and amphibious forces.
The battle has been referred to as the "typhoon of steel" in English, and tetsu no ame or tetsu no bōfū in Japanese.