Operation: Iceberg (Battle of Okinawa)

The Battle of Okinawa (Japanese: 沖縄戦, Hepburn: Okinawa-sen), codenamed Operation Iceberg,[26]: 17  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.[27][28] The initial invasion of Okinawa on 1 April 1945 was the largest amphibious assault in the Pacific Theater of World War II.[29][30] 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 United States created the Tenth Army, a cross-branch force consisting of the U.S. Army 7th, 27th, 77th and 96th Infantry Divisions with the 1st, 2nd, and 6th Marine Divisions, to seize the island. The Tenth Army was unique because it had its own Tactical Air Force (joint Army-Marine command) and was supported by combined naval and amphibious forces. Opposing the Allied forces on the ground was the Japanese Lieutenant General Mitsuru Ushijima's Thirty-Second Army, a mixed force consisting of regular army troops, naval infantry and conscripted local Okinawans. There were about 100,000 Japanese troops on Okinawa at the onset of the invasion. The battle was the longest sustained carrier campaign of the Second World War.[31] The battle has been referred to as the "typhoon of steel" in English, known in Japanese as "tetsu no bōfū".[32][33] The nicknames refer to the ferocity of the fighting, the intensity of Japanese kamikaze attacks and the sheer numbers of Allied ships and armored vehicles that assaulted the island. The battle was the bloodiest and fiercest in the Pacific Ocean Theatre, with some 50,000 Allied and around 100,000 Japanese casualties,[34][18]: 473–474  also including local Okinawans conscripted into the Japanese Army.[23] According to local authorities, at least 149,425 Okinawan people were killed, died by coerced suicide or went missing.[35] In the naval operations surrounding the battle, both sides lost considerable numbers of ships and aircraft, including the Japanese battleship Yamato. After the battle, Okinawa provided the victorious Allies with a fleet anchorage, troop staging areas, and airfields in close proximity to Japan as they planned to invade the Japanese home islands. Order of battle: Allied: In all, the US Army had over 103,000 soldiers (of these, 38,000+ were non-divisional artillery, combat support and HQ troops, with another 9,000 service troops),[36]: 39  over 88,000 Marines and 18,000 Navy personnel (mostly Seabees and medical personnel).[36]: 40  At the start of the Battle of Okinawa, the US Tenth Army had 182,821 personnel under its command.[36]: 40  It was planned that Lieutenant General Simon Bolivar Buckner Jr. would report to Vice Admiral Richmond K. Turner until the amphibious phase was completed, after which he would report directly to Admiral Raymond A. Spruance. Total aircraft provided by the US Navy, Marine and Army Air Force exceeded 3,000 over the course of the battle, including fighters, attack aircraft, scout planes, bombers and dive-bombers. The invasion was supported by a fleet consisting of 18 battleships, 27 cruisers, 177 destroyers/destroyer escorts, 39 aircraft carriers (11 fleet carriers, 6 light carriers and 22 escort carriers) and various support and troop transport ships.[37] The British naval contingent accompanied 251 British naval aircraft and included a British Commonwealth fleet with Australian, New Zealand and Canadian ships and personnel.[38] Japanese: The Japanese land campaign (mainly defensive) was conducted by the 67,000-strong (77,000 according to some sources) regular 32nd Army and some 9,000 Imperial Japanese Navy troops at Oroku Naval Base (only a few hundred of whom had been trained and equipped for ground combat), supported by 39,000 drafted local Ryukyuan people (including 24,000 hastily drafted rear militia called Boeitai and 15,000 non-uniformed laborers). The Japanese had used kamikaze tactics since the Battle of Leyte Gulf, but now for the first time they became a major institutionalized aspect of the Japanese defensive strategy. Between the American landing on 1 April and 25 May, seven major kamikaze attacks were attempted, involving more than 1,500 planes. The 32nd Army initially consisted of the 9th, 24th and 62nd Divisions and the 44th Independent Mixed Brigade. The 9th Division was moved to Taiwan before the invasion, resulting in shuffling of Japanese defensive plans. Primary resistance was to be led in the south by Lieutenant General Mitsuru Ushijima, his chief of staff, Lieutenant General Isamu Chō and his chief of operations, Colonel Hiromichi Yahara. Yahara advocated a defensive strategy, whilst Chō advocated an offensive one. In the north, Colonel Takehiko Udo was in command. The naval troops were led by Rear Admiral Minoru Ōta. They expected the Americans to land 6–10 divisions against the Japanese garrison of two and a half divisions. The staff calculated that superior quality and numbers of weapons gave each US division five or six times the firepower of a Japanese division. To this, would be added the Americans' abundant naval and air firepower. Among the 21 male and female secondary schools that made up these student corps, 2,000 students died on the battlefield. Even with the female students acting mainly as nurses to Japanese soldiers, they were still exposed to the harsh conditions of war.[39] Naval battle: There was a hypnotic fascination to the sight so alien to our Western philosophy. We watched each plunging kamikaze with the detached horror of one witnessing a terrible spectacle rather than as the intended victim. We forgot self for the moment as we groped hopelessly for the thought of that other man up there. — Vice Admiral C.R. Brown, US Navy[40]: 711 The US Navy's Task Force 58, deployed to the east of Okinawa with a picket group of 6 to 8 destroyers, kept 13 carriers (7 fleet carriers and 6 light carriers) on duty from 23 March to 27 April and a smaller number thereafter. Until 27 April, a minimum of 14 and up to 18 escort carriers were in the area at all times. Until 20 April, British Task Force 57, with 4 large and 6 escort carriers, remained off the Sakishima Islands to protect the southern flank.[18]: 97 The protracted length of the campaign under stressful conditions forced Admiral Chester W. Nimitz to take the unprecedented step of relieving the principal naval commanders to rest and recuperate. Following the practice of changing the fleet designation with the change of commanders, US naval forces began the campaign as the US 5th Fleet under Admiral Spruance, but ended it as the 3rd Fleet under Admiral Halsey. Japanese air opposition had been relatively light during the first few days after the landings. However, on 6 April the expected air reaction began with an attack by some 400 Japanese planes from Kyushu. Similar air attacks continued through April.[41] From 26 March to 30 April, 20 American ships were sunk and 157 damaged by enemy action. By 30 April the Japanese had lost more than 1,100 planes to Allied naval forces alone.[18]: 102 Between 6 April and 22 June, the Japanese flew 1,465 kamikaze aircraft in large-scale attacks from Kyushu, 185 individual kamikaze sorties from Kyushu, and 250 individual kamikaze sorties from Taiwan, then called Formosa. While US intelligence estimated there were 89 planes on Formosa, the Japanese actually had about 700, dismantled or well camouflaged and dispersed into scattered villages and towns; the US Fifth Air Force disputed Navy claims of kamikaze coming from Formosa.[42][clarification needed] The ships lost were smaller vessels, particularly the destroyers of the radar pickets, as well as destroyer escorts and landing ships. While no major Allied warship was lost, several fleet carriers were severely damaged. Land-based Shin'yō-class suicide motorboats were also used in the Japanese suicide attacks, although Ushijima had disbanded the majority of the suicide boat battalions before the battle because of expected low effectiveness against a superior enemy. The boat crews were re-formed into three additional infantry battalions.[43] Operation Ten-Go: Operation Ten-Go (Ten-gō sakusen) was the attempted attack by a strike force of ten Japanese surface vessels, led by Yamato and commanded by Admiral Seiichi Itō. This small task force had been ordered to fight through enemy naval forces, then beach Yamato and fight from shore, using her guns as coastal artillery and her crew as naval infantry. The Ten-Go force was spotted by submarines shortly after it left the Japanese home waters and was intercepted by US carrier aircraft. Under attack from more than 300 aircraft over a two-hour span, the world's largest battleship sank on 7 April 1945 after a one-sided battle, long before she could reach Okinawa. (US torpedo bombers were instructed to aim for only one side to prevent effective counter flooding by the battleship's crew, and to aim for the bow or the stern where armor was believed to be the thinnest.) Of Yamato's screening force, the light cruiser Yahagi and four of the eight destroyers were also sunk. The Imperial Japanese Navy lost some 3,700 sailors, including Admiral Itō, at the cost of ten US aircraft and twelve airmen. British Pacific Fleet: The British Pacific Fleet, taking part as Task Force 57, was assigned the task of neutralizing the Japanese airfields in the Sakishima Islands, which it did successfully from 26 March to 10 April. On 10 April its attention was shifted to airfields in northern Formosa. The force withdrew to San Pedro Bay on 23 April. On 1 May, the British Pacific Fleet returned to action, subduing the airfields as before, this time with naval bombardment as well as aircraft (they only used aircraft during their first mission of destroying airfields in the Sakishima Islands).[44] Several kamikaze attacks caused significant damage, but as the Royal Navy carriers had armored flight decks, they experienced only a brief interruption to their force's operations.[45][46] Land battle: The land battle took place over about 81 days beginning on 1 April 1945. The first Americans ashore were soldiers of the 77th Infantry Division who landed in the Kerama Islands, 15 mi (24 km) west of Okinawa on 26 March. Subsidiary landings followed, and the Kerama group was secured over the next five days. In these preliminary operations, the 77th Infantry Division suffered 27 dead and 81 wounded, while the Japanese dead and captured numbered over 650. On March 28, 1945, 394 civilians on Tokashiki island were forced by Japanese soldiers to kill themselves after the landing of US troops.[47][48] The operation provided a protected anchorage for the fleet and eliminated the threat from suicide boats.[18]: 50–60 On 31 March, Marines of the Amphibious Reconnaissance Battalion landed without opposition on Keise Shima, four islets just 8 mi (13 km) west of the Okinawan capital of Naha. A group of 155 mm (6.1 in) "Long Tom" artillery pieces went ashore on the islets to cover operations on Okinawa.[18]: 57 Northern Okinawa: The main landing was made by the XXIV Corps and the III Amphibious Corps on the Hagushi beaches on the western coast of Okinawa on 1 April. The 2nd Marine Division conducted a demonstration off the Minatoga beaches on the southeastern coast to deceive the Japanese about American intentions and delay movement of reserves from there.[18]: 68–74 Tenth Army swept across the south-central part of the island with relative ease, capturing the Kadena and the Yomitan airbases within hours of the landing.[26]: 67–69 [18]: 74–75  In light of the weak opposition, General Buckner decided to proceed immediately with Phase II of his plan, the seizure of northern Okinawa. The 6th Marine Division headed up the Ishikawa Isthmus and by 7 April had sealed off the Motobu Peninsula.[18]: 138–141 Six days later on 13 April, the 2nd Battalion, 22nd Marine Regiment, reached Hedo Point at the northernmost tip of the island. By this point, the bulk of the Japanese forces in the north (codenamed Udo Force) were cornered on the Motobu Peninsula. The terrain was mountainous and wooded, with the Japanese defenses concentrated on Mount Yaedake, a twisted mass of rocky ridges and ravines on the center of the peninsula. There was heavy fighting before the Marines finally cleared Yaedake on 18 April.[18]: 141–148  However, this was not the end of ground combat in northern Okinawa. On 24 May, the Japanese mounted Operation Gi-gou: a company of Giretsu Kuteitai commandos were airlifted in a suicide attack on Yomitan. They destroyed 70,000 US gallons (260,000 L) of fuel and nine planes before being killed by the defenders, who lost two men. Meanwhile, the 77th Infantry Division assaulted Ie Shima, a small island off the western end of the peninsula, on 16 April. In addition to conventional hazards, the 77th Infantry Division encountered kamikaze attacks and even local women armed with spears. There was heavy fighting before the area was declared secured on 21 April and became another airbase for operations against Japan.[18]: 149–183 Southern Okinawa: While the 6th Marine Division cleared northern Okinawa, the US Army 96th and 7th Infantry Divisions wheeled south across the narrow isthmus of Okinawa. The 96th Infantry Division began to encounter fierce resistance in west-central Okinawa from Japanese troops holding fortified positions east of Highway No. 1 and about 5 mi (8 km) northwest of Shuri, from what came to be known as Cactus Ridge.[18]: 104–105  The 7th Infantry Division encountered similarly fierce Japanese opposition from a rocky pinnacle located about 1,000 yd (910 m) southwest of Arakachi (later dubbed "The Pinnacle"). By the night of 8 April, American troops had cleared these and several other strongly fortified positions. They suffered over 1,500 battle casualties in the process while killing or capturing about 4,500 Japanese. Yet the battle had only begun, for it was realized that "these were merely outposts," guarding the Shuri Line.[18]: 105–108 The next American objective was Kakazu Ridge (26.259°N 127.737°E)(see ja:嘉数の戦い), two hills with a connecting saddle that formed part of Shuri's outer defenses. The Japanese had prepared their positions well and fought tenaciously. The Japanese soldiers hid in fortified caves. American forces often lost personnel before clearing the Japanese out from each cave or other hiding place. The Japanese sent out Okinawans at gunpoint to obtain water and supplies for them, which led to civilian casualties. The American advance was inexorable but resulted in a high number of casualties on both sides.[18]: 110–125  Meanwhile, American forces also faced heavy resistance at the Maeda Ridge, also known as Hacksaw Ridge (see ja:前田の戦い). As the American assault against Kakazu Ridge stalled, Lieutenant General Ushijima—influenced by General Chō—decided to take the offensive. On the evening of 12 April, the 32nd Army attacked American positions across the entire front. The Japanese attack was heavy, sustained, and well organized. After fierce close combat, the attackers retreated, only to repeat their offensive the following night. A final assault on 14 April was again repulsed. The effort led the 32nd Army's staff to conclude that the Americans were vulnerable to night infiltration tactics but that their superior firepower made any offensive Japanese troop concentrations extremely dangerous, and they reverted to their defensive strategy.[18]: 130–137 The 27th Infantry Division, which had landed on 9 April, took over on the right, along the west coast of Okinawa. General John R. Hodge now had three divisions in the line, with the 96th in the middle and the 7th to the east, with each division holding a front of only about 1.5 mi (2.4 km). Hodge launched a new offensive on 19 April with a barrage of 324 guns, the largest ever in the Pacific Ocean Theater. Battleships, cruisers, and destroyers joined the bombardment, which was followed by 650 Navy and Marine planes attacking the Japanese positions with napalm, rockets, bombs, and machine guns. The Japanese defenses were sited on reverse slopes, where the defenders waited out the artillery barrage and aerial attack in relative safety, emerging from the caves to rain mortar rounds and grenades upon the Americans advancing up the forward slope.[18]: 184–194 A tank assault to achieve breakthrough by outflanking Kakazu Ridge failed to link up with its infantry support attempting to cross the ridge and therefore failed with the loss of 22 tanks. Although flame tanks cleared many cave defenses, there was no breakthrough, and the XXIV Corps suffered 720 casualties. The losses might have been greater except for the fact that the Japanese had practically all of their infantry reserves tied up farther south, held there by another feint off the Minatoga beaches by the 2nd Marine Division that coincided with the attack.[18]: 196–207 At the end of April, after Army forces had pushed through the Machinato defensive line,[49] the 1st Marine Division relieved the 27th Infantry Division and the 77th Infantry Division relieved the 96th. When the 6th Marine Division arrived, the III Amphibious Corps took over the right flank and Tenth Army assumed control of the battle.[18]: 265 On 4 May, the 32nd Army launched another counter-offensive. This time, Ushijima attempted to make amphibious assaults on the coasts behind American lines. To support his offensive, the Japanese artillery moved into the open. By doing so, they were able to fire 13,000 rounds in support, but effective American counter-battery fire destroyed dozens of Japanese artillery pieces. The attack failed.[18]: 283–302 Buckner launched another American attack on 11 May. Ten days of fierce fighting followed. On 13 May, troops of the 96th Infantry Division and 763rd Tank Battalion captured Conical Hill (26.21°N 127.75°E). Rising 476 ft (145 m) above the Yonabaru coastal plain, this feature was the eastern anchor of the main Japanese defenses and was defended by about 1,000 Japanese. Meanwhile, on the opposite coast, the 1st and 6th Marine Divisions fought for "Sugar Loaf Hill" (26.222°N 127.696°E). The capture of these two key positions exposed the Japanese around Shuri on both sides. Buckner hoped to envelop Shuri and trap the main Japanese defending force.[18]: 311–359 By the end of May, monsoon rains which had turned contested hills and roads into a morass exacerbated both the tactical and medical situations. The ground advance began to resemble a World War I battlefield, as troops became mired in mud, and flooded roads greatly inhibited evacuation of wounded to the rear. Troops lived on a field sodden by rain, part garbage dump and part graveyard. Unburied Japanese and American bodies decayed, sank in the mud and became part of a noxious stew. Anyone sliding down the greasy slopes could easily find their pockets full of maggots at the end of the journey.[18]: 364–370 From 24 to 27 May the 6th Marine Division cautiously occupied the ruins of Naha, the largest city on the island, finding it largely deserted.[18]: 372–377 On 26 May aerial observers saw large troop movements just below Shuri. On 28 May Marine patrols found recently abandoned positions west of Shuri. By 30 May the consensus among Army and Marine intelligence was that the majority of Japanese forces had withdrawn from the Shuri Line.[18]: 391–392  On 29 May the 1st Battalion, 5th Marines (1/5 Marines) occupied high ground 700 yards (640 m) east of Shuri Castle and reported that the castle appeared undefended. At 10:15 Company A, 1/5 Marines occupied the castle.[18]: 395–496 Shuri Castle had been shelled by the battleship USS Mississippi for three days before this advance.[50] The 32nd Army withdrew to the south and thus the Marines had an easy task of securing Shuri Castle.[50][51] The castle, however, was outside the 1st Marine Division's assigned zone, and only frantic efforts by the commander and staff of the 77th Infantry Division prevented an American airstrike and artillery bombardment which would have resulted in many friendly fire casualties.[18]: 396 On 29 May a Confederate flag was raised over Shuri Castle,[52] before being removed and replaced by a US flag three days later on orders of General Buckner; himself the son of a Confederate General.[53] The Japanese retreat, although harassed by artillery fire, was conducted with great skill at night and aided by the monsoon storms. The 32nd Army was able to move nearly 30,000 personnel into its last defense line on the Kiyan Peninsula, which ultimately led to the greatest slaughter on Okinawa in the latter stages of the battle, including the deaths of thousands of civilians. In addition, there were 9,000 IJN troops supported by 1,100 militia, with approximately 4,000 holed up at the underground headquarters on the hillside overlooking the Okinawa Naval Base in the Oroku Peninsula, east of the airfield.[18]: 392–394 On 4 June, elements of the 6th Marine Division launched an amphibious assault on the peninsula. The 4,000 Japanese sailors, including Admiral Ōta, all committed suicide within the hand-built tunnels of the underground naval headquarters on 13 June.[18]: 427–434  By 17 June, the remnants of Ushijima's shattered 32nd Army were pushed into a small pocket in the far south of the island to the southeast of Itoman.[18]: 455–4661 On 18 June, General Buckner was killed by Japanese artillery fire while monitoring the progress of his troops from a forward observation post. Buckner was replaced by Major General Roy Geiger. Upon assuming command, Geiger became the only US Marine to command a numbered army of the US Army in combat; he was relieved five days later by General Joseph Stilwell. On 19 June, Brigadier General Claudius Miller Easley, the commander of the 96th Infantry Division, was killed by Japanese machine-gun fire, also while checking on the progress of his troops at the front.[18]: 461 The last remnants of Japanese resistance ended on 21 June, although some Japanese continued hiding, including the future governor of Okinawa Prefecture, Masahide Ōta.[54] Ushijima and Chō committed suicide by seppuku in their command headquarters on Hill 89 in the closing hours of the battle.[18]: 468–471  Colonel Yahara had asked Ushijima for permission to commit suicide, but the general refused his request, saying: "If you die there will be no one left who knows the truth about the battle of Okinawa. Bear the temporary shame but endure it. This is an order from your army commander."[40]: 723  Yahara was the most senior officer to have survived the battle on the island, and he later authored a book titled The Battle for Okinawa. On 22 June Tenth Army held a flag-raising ceremony to mark the end of organized resistance on Okinawa. On 23 June a mopping-up operation commenced, which concluded on 30 June.[18]: 471–473 On 15 August 1945, Admiral Matome Ugaki was killed while part of a kamikaze raid on Iheyajima island. The official surrender ceremony was held on 7 September, near the Kadena Airfield. [This bot will simulate an extra hard,realistic and historical roleplay of Operation Iceberg,sensitive themes such as suicide charges are present.]