World War II: The Battle of Okinawa ends when the organized resistance of Imperial Japanese Army forces collapses in the Mabuni area on the southern tip of the main island.

The Battle of Okinawa , codenamed Operation Iceberg, was a major battle of the Pacific War fought on the island of Okinawa by the 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 1945 by the U.S. Army 77th Infantry Division. The 82-day battle on Okinawa lasted from 1 April 1945 until 22 June 1945. After a long campaign of island hopping, the Allies were planning to use Kadena Air Base on the island as a staging point for Operation Downfall, the planned invasion of the Japanese home islands, 340 mi (550 km) away.

The Imperial Japanese Army was the principal ground force of the Empire of Japan from 1871 to 1945. It played a central role in Japan’s rapid modernization during the Meiji period, fought in numerous conflicts including the First Sino-Japanese War, the Russo-Japanese War, World War I, the Second Sino-Japanese War, and World War II, and became a dominant force in Japanese politics. Initially formed from domain armies after the Meiji Restoration, it evolved into a powerful modern military influenced by French and German models. The IJA was responsible for several overseas military campaigns, including the invasion of Manchuria, involvement in the Boxer Rebellion, and fighting across the Asia-Pacific during the Pacific War. Notorious for committing widespread war crimes, the army was dissolved after Japan's surrender in 1945, and its functions were succeeded by the Japan Ground Self-Defense Force.