This largest island in the Ryukyus was invaded by American forces, supported by sundry British and other Western Allied naval elements, on April 1, 1945. It was not secured for nearly three months and only after heavy fighting and great loss of life, including of civilians who committed suicide or were cut down by fanatic Japanese officers, or were simply caught in the crossfire. Before the invasion, Imperial General Headquarters thought the enemy might land on Taiwan instead. As part of the Sho-Gö defensive plan, the Japanese moved one of their best Army divisions to Taiwan from Okinawa to await an invasion that never came. Imperial General Headquarters feared that if Okinawa fell it would be used as a major base to bomb Japan. The Western Allies agreed, but saw it also as a way to threaten the Japanese Empire in northern China and Manchuria. That revealed a grim Allied determination about how the war would end: in massive land fighting on the mainland of Asia, eventually involving the Red Army, and not ceasing until all Japanese resistance was crushed. That assessment of the future of the war was not shared by Japanese leaders, many of whom clung to delusional notions about what they might reasonably expect from an enemy coalition whose formal demand was unconditional surrender.
The assault on Okinawa was made by air, land, and sea forces larger than the D-Day (June 6, 1944) fleet that supported the Normandy campaign. The Imperial Japanese Navy never imagined such naval power in its wildest visions or nightmares: over 1,500 enemy warships approached Okinawa at the end of March 1945. Most were American, but there were also Australian and British ships in the armada. Preliminary air attacks were massive, launched from British and American carriers as well as by long-range B-29s operating out of the Marianas. Extensive bombing was conducted against air bases on Kyushu, but many aircraft on that island were well-concealed and survived the assault. The small Kerama Islands were taken on March 26-27, in advance of the main landings on Okinawa. Hundreds of ‘Shinyo’ suicide attack boats and other suicide weapons were discovered on the small islands. The Keramas were used for long-range, land-based artillery support of the main landings and as a safe harbor for damaged ships. Operation ICEBERG landed 184,000 troops of newly formed U.S. 10th Army on Okinawa on the first day. A total force of 545,000 ultimately made it ashore. Waves of nearly 2,000 kamikaze met the invasion fleet, the largest in naval history. Over the following months suicide pilots sank 38 U.S. warships and damaged nearly 200 more, in a campaign that saw over 3,000 kamikaze attacks. A suicide flotilla of Japanese warships also sortied. Centered on the IJN Yamato, it made a run for the beaches but was stopped cold on April 6, when 380 carrier-based aircraft from Task force 58 intercepted the squadron and sank ‘Yamato,’ the lone cruiser in the flotilla, and four destroyers in the lopsided action called the ‘Battle of the East China Sea.’
BB Yamato's last operation.
The Japanese on Okinawa did not meet the invasion on the beaches. Instead, over 100,000 men of Japanese 32nd Army waited inland in prepared and well-fortified defenses on the northern Motobu peninsula and in a separate belt of fortifications across the southern Oroku peninsula. Motobu was cleared by U.S. marines by April 20. An assault on the southern defensive belts began on April 19. The Japanese counterattacked on May 4, then withdrew to an even deeper set of fortifications on Oroku. The fighting was close and intense, with flamethrowers an essential weapon used to winnow out bitterender resistance. On June 22 Okinawa was formally declared secure. Over the course of the land battle the Japanese lost an astonishing 7,800 planes, and a lesser number of pilots. Over 7,000 U.S. troops died in their bloodiest battle of the Pacific War. The Americans took 49,000 total casualties, including 4,907 sailors killed or wounded by kamikaze, the highest loss rate in any battle of the war. Japan lost 107,539 military dead, over one-quarter of whom were blasted or incinerated to death or sealed inside caves. About 11,000 Japanese military prisoners were taken, first truly significant Japanese surrender in the Pacific War. About one quarter of all civilians on the island also died, some 75,000 souls in all. Many had been encouraged—and some were forced—by Japanese officers to seal themselves in death caves or to hurl their children and themselves into the sea. The death agony of whole families was captured on film.