Last major battle of World War II in the Pacific and the largest and most complicated amphibious operation in the theater. Okinawa, the largest of the Ryukyu Islands and only 350 miles from the Japanese home island of Kyushu, had long been regarded as the last stepping-stone before a direct Allied attack on Japan. The island is 60 miles long and at most 18 miles wide. Japan had gained possession of the island in 1875. Japanese leaders considered the defense of Okinawa as their last chance to hold off an invasion of the homeland, and they were prepared for their forces to battle to the death. Allied strategists decided that a major amphibious operation, code-named ICEBERG, would be mounted to take the island to secure harbor and air-base facilities for the projected attack on the Japanese home islands. Taking the island would also sever Japanese communications with south China.
Admiral Raymond Spruance, commander of Fifth Fleet, had overall charge of the invasion operation. The covering force included 18 battleships and 40 carriers in Vice Admiral Marc A. Mitscher's Fast Carrier Force (TF-58) and the British component commanded by Vice Admiral H. B. Rawlings (TF-57, a battleship and four carriers, plus supporting ships, 22 in all). The lifting force of Vice Admiral Richmond K. Turner's Joint Expeditionary Force, TF-51, comprised some 1,300 ships. Operation ICEBERG included the largest number of ships involved in a single operation during the entire Pacific war.
The land assault force consisted of U.S. Army Lieutenant General Simon Bolivar Buckner's Tenth Army of some 180,000 men. Tenth Army included Major General Roy S. Geiger's III Marine Amphibious Corps (1st, 2nd, and 6th Divisions) and Army Major General John R. Hodge's XXIV Army Corps (7th, 27th, 77th, and 96th Divisions). The Japanese defenders were formed into the Thirty-Second Army (Ryukus). It comprised four divisions (9th, 24th, 62nd, and the 28th on Sakishima) plus additional units. Lieutenant General Mitsuru Ushijima commanded about 130,000 men, including the 20,000-man Okinawan Home Guard. The Japanese constructed a formidable defensive system, particularly on the southern part of the island.
The invasion was originally scheduled for 1 March 1945, but delays in the Philippines Campaign and at Iwo Jima caused ICEBERG to be delayed for several weeks. The operation began with the occupation of the Kerama Islets, 15 miles west of Okinawa, on 16 March 1945. Five days later, a landing was made on Keise-Jima, from which point artillery fire could be brought to bear on Okinawa itself. Then on 1 April, Easter Sunday, the landing began with a feint toward the southeastern shore of the island. The real assault was made by 60,000 U.S. troops landing on the central stretch of Okinawa's west coast. They quickly seized two nearby airfields and advanced east to cut the island's narrow waist. The Marines and Army troops attained most of their initial objectives within four days.
Ushijima had concentrated the bulk of his defenders out of range of Allied naval guns off the beaches and behind the strong Shuri line at the southern end of the island. There, the Japanese planned to inflict as much damage as possible on the invaders, supported by the last units of the Imperial Fleet and kamikaze raids. U.S. forces encountered the Shuri line for the first time on 4 April. They fought for eight days to take a ridge and clear the Japanese from numerous caves. Fighting was intense as the Japanese defended every inch of ground. The 1st Marine Division finally took Shuri Castle on 29 May. The Japanese then withdrew to the south to establish another defensive line at Yaeju Dake and Yazu Dake. Fierce fighting continued until most Japanese resistance had been eliminated by 21 June. During the battle for Okinawa, both commanders died within five days of each other; General Buckner died of shrapnel wounds inflicted by Japanese artillery at a forward observation post on 18 June, and General Ushijima committed suicide on 23 June.
While the battle had raged ashore, fighting in the waters around the island was just as intense. Japanese kamikaze attacks reached their highest level of the war as the suicide pilots flung themselves against the Allied fleet. Several thousand pilots immolated themselves against U.S. and British ships, sinking 36 and damaging another 368. The largest kamikaze was the giant battleship Yamato
, dispatched to Okinawa with sufficient fuel for only a one-way trip. She was to inflict as much damage as possible before being destroyed; the Japanese hoped the Yamato might finish off the Allied fleet after the latter had been weakened by kamikaze attacks, then beach herself as a stationary battery. This mission came to naught on 7 April when the Yamato
was attacked by U.S. carrier aircraft. Hit repeatedly by bombs and torpedoes, she sank long before reaching the invasion site.
Okinawa was officially declared secure on 2 July. Both sides had suffered horrendous casualties. More than 107,000 Japanese and Okinawan military and civilian personnel died. On the U.S. side, the army lost 12,520 dead and 36,631 wounded. The Marines suffered 2,938 dead and 13,708 wounded. The navy lost 4,907 men killed and 4,874 wounded, primarily from kamikaze attacks. The navy was the only service in the battle in which the dead exceeded the wounded. This figure was greater than the navy's casualties in all U.S. wars to that date. The Battle of Okinawa was the costliest battle for the Americans of the Pacific war; this was used to support the case for bringing the war to an end by means other than the invasion of Japan itself and certainly influenced the decision by the United States to use atomic bombs.
James H. Willbanks
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