Twentieth Air Force

Operation Matterhorn was the name for the B-29 Superfortress offensive against the Empire of Japan from airfields in China. On 10 April 1944, the Joint Chiefs of Staff (JCS) informally approved Operation Matterhorn. The operational vehicle was to be the 58th Bombardment Wing (Very Heavy) of the XX Bomber Command.^[3]

The headquarters of the XX Bomber Command had been established at Kharagpur India on 28 March 1944. The commander was General Kenneth B. Wolfe. The first B-29 reached its base in India on 2 April 1944. In India, existing airfields at Kharagpur, Chakulia, Piardoba and Dudkhundi had been converted for B-29 use. All of these bases were located in southern Bengal and were not far from port facilities at Calcutta.^[3]

The first B-29 bombing raid from India took place on 5 June 1944. Ninety-eight B-29s took off from bases in eastern India to attack the Makasan railroad yards at Bangkok, Thailand. Bombardment operations against Japan were planned to be carried out from bases in China. There were four sites in the Chengtu area of China that were assigned to the B-29 operation—at Kwanghan, Kuinglai, Hsinching, and Pengshan. The primary flaw in the Operation Matterhorn plan was that all the supplies of fuel, bombs, and spares needed to support the forward bases in China had to be flown in from India over the Hump, since Japanese control of the seas around the Chinese coast made seaborne supply of China impossible.^[3]

By mid-June, enough supplies had been stockpiled at Chinese forward bases to permit the launching of a single attack against targets in Japan. It was a nighttime raid to be carried out on the night of 14/15 June 1944 against the Imperial Iron and Steel Works at Yawata on Kyūshū. Unfortunately, the Japanese had been warned of the approaching raid and the city of Yawata was blacked out and haze and/or smoke helped to obscure the target. Only 15 aircraft bombed visually while 32 bombed by radar. Only one bomb actually hit anywhere near the intended target, and the steel industry was essentially untouched. Although very little damage was actually done, the Yawata raid was hailed as a great victory in the American press, since it was the first time since the Doolittle Raid of April 1942 that American aircraft had hit the Japanese home islands.^[3]

On the night 10–11 August, 56 B-29s staged through British air bases in Ceylon attacked the Plajdoe oil storage facilities at Palembang on Sumatra in Indonesia. This involved a 4030-mile, 19-hour mission from Ceylon to Sumatra, the longest American air raid of the war. Other B-29s laid mines in the Moesi River. At the same time, a third batch of B-29s attacked targets in Nagasaki. These raids all showed a lack of operational control and inadequate combat techniques, drifting from target to target without a central plan and were largely ineffective.^[3]

In Washington, it was decided that new leadership was needed for Twentieth Air Force. General Wolfe's replacement was Major General Curtis LeMay, who arrived in India on 29 August. Supply problems and aircraft accidents were still preventing a fully effective concentration of force and effort. In addition, Japanese defensive efforts were becoming more effective.^[3]

By late 1944, it was becoming apparent that B-29 operations against Japan staged out of bases in China and India were far too expensive in men and materials and would have to be stopped. In December 1944, the Joint Chiefs of Staff made the decision that Operation Matterhorn would be phased out, and the 58th Bombardment Wing's B-29s would be moved to newly captured bases in the Marianas in the central Pacific. The last raid out of China was flown on 15 January 1945, which was an attack on targets in Formosa (Taiwan). The 58th Bombardment Wing then redeployed to new bases in the Marianas in February.^[3]

See: XXI Bomber Command for expanded history

The Marianas chain of islands, consisting primarily of Saipan, Tinian, and Guam, were considered as being ideal bases from which to launch B-29 Superfortress operations against Japan. The islands were about 1500 miles from Tokyo, a range which the B-29s could just about manage. Most important of all, they could be put on a direct supply line from the United States by ship. The XXI Bombardment Command had been assigned the overall responsibility of the B-29 operations out of the Marianas bases.^[4][5]

The first B-29 arrived on Saipan on 12 October 1944. It was piloted by General Hansell himself. By 22 November, over 100 B-29s were on Saipan. The XXI Bomber Command was assigned the task of destroying the aircraft industry of Japan in a series of high-altitude, daylight precision attacks.^[4][5]

The first raid against Japan took place on 24 November 1944. The target was the Nakajima Aircraft Company's Musashi engine plant just outside Tokyo. 111 B-29s took off, Seventeen of them had to abort due to the usual spate of engine failures. The remainder approached the target at altitudes of 27–32,000 feet. For the first time, the B-29 encountered the jet stream, which was a high-speed wind coming out of the west at speeds as high as 200 mph at precisely the altitudes at which the bombers were operating. This caused the bomber formations to be disrupted and made accurate bombing impossible.^[4][5]

Concerned about the relative failure of the B-29 offensive to deal any crippling blows to Japan, General LeMay issued a new directive on 19 February. General LeMay had analyzed the structure of the Japanese economy, which depended heavily on cottage industries housed in cities close to major industrial areas. By destroying these feeder industries, the flow of vital components to the central plants could be slowed, disorganizing production of weapons vital to Japan. He decided to do this by using incendiary bombs rather than purely high-explosive bombs, which would, it was hoped, cause general conflagrations in large cities like Tokyo or Nagoya, spreading to some of the priority targets.^[4][5]

The first raid to use these new techniques was on the night of 9–10 March against Tokyo. Another wing—the 314th Bombardment Wing (19th, 29th, 39th, and 330th BG) commanded by Brig. Gen. Thomas S. Power—had arrived in the Marianas and was stationed at North Field on Guam. A total of 302 B-29s participated in the raid, with 279 arriving over the target. The raid was led by special pathfinder crews who marked central aiming points. It lasted for two hours. The raid was a success beyond General LeMay's wildest expectations. The individual fires caused by the bombs joined to create a general conflagration due to strong winds of some 17 to 28 mph (27 to 45 km/h) at ground level, that prevented a more specific firestorm event. When it was over, sixteen square miles (41 km².) of the center of Tokyo had gone up in flames and nearly 84,000 people had been killed. Fourteen B-29s were lost. The B-29 was finally beginning to have an effect.^[4][5]

بحلول منتصف يونيو، كانت معظم المدن اليابانية الكبرى قد دُمرت بالكامل، فأمر ليماي بشن غارات حارقة جديدة على 58 مدينة يابانية أصغر. في ذلك الوقت، لم تكن غارات قاذفات بي-29 تواجه مقاومة تُذكر من المقاتلات اليابانية. وفي أواخر يونيو، شعر طاقم بي-29 بثقة كافية دفعتهم إلى البدء بإلقاء منشورات تحذيرية للسكان من الهجمات الوشيكة، أعقبها بعد ثلاثة أيام غارة دمرت المنطقة الحضرية المستهدفة تدميراً كاملاً. وبحلول نهاية يونيو، بدأت تظهر على السكان المدنيين علامات الذعر، وبدأ مجلس الوزراء الإمبراطوري لأول مرة في التفكير في التفاوض لإنهاء الحرب. ومع ذلك، في ذلك الوقت، كان الجيش الياباني مصراً على مواصلة القتال حتى النهاية المريرة. ^{[ 4 ] [ 5 ]}

في يونيو 1945، جُمعت قيادتا القصف XX وXXI تحت قيادة القوات الجوية الاستراتيجية الأمريكية في المحيط الهادئ (USASTAF)، بقيادة الجنرال كارل أ. سباتز . انتهى تاريخ قيادة القصف XXI في 16 يوليو 1945، حيث أُعيد تسميتها في ذلك التاريخ إلى مقر وسرب المقر، التابع للقوات الجوية العشرين . أنهى هذا التغيير وجود قيادة القصف XXI ككيان مستقل، إذ دُمجت في الهيكل التنظيمي الداخلي للقوات الجوية العشرين، ووُضعت تحت قيادة القوات الجوية الاستراتيجية الأمريكية في المحيط الهادئ. ^{[ 4 ] [ 5 ]}

للاطلاع على تاريخ موسع ، انظر: القوات الجوية الاستراتيجية الأمريكية في المحيط الهادئ والقصف الذري لهيروشيما وناغازاكي

في 16 يوليو 1945، أُعيد تنظيم القيادات العسكرية الأمريكية، حيث وُضعت القوات الجوية العشرين تحت قيادة وسيطرة القوات الجوية الاستراتيجية الأمريكية الجديدة في المحيط الهادئ . وتولت القوات الجوية العشرين قيادة أسراب قاذفات بي-29 المتمركزة مباشرة في جزر ماريانا، بينما تولت القوات الجوية الثامنة، التي أُعيد نشرها حديثًا ، قيادة أسراب قاذفات بي-29 المتمركزة في أوكيناوا. وجاء هذا التغيير تمهيدًا للغزو المخطط لليابان ( عملية داونفول ) المقرر انطلاقه في أكتوبر 1945. وتم حلّ قيادة القاذفات الحادية والعشرين، وأصبحت تحت السيطرة المباشرة للقوات الجوية العشرين. ^{[ 4 ]}

By mid-July 1945, the combat missions over Japan were essentially un-opposed, with VII Fighter Command long range P-51 Mustangs operating from captured Iwo Jima airfields flying escort to the Marianas-based B-29s. Missions primarily consisted of low-level incendiary raids on smaller Japanese cities, both at night as well as daylight on a daily basis. The 315th Bombardment Wing, which became operational at the beginning of July, carried out a series of strikes against oil production facilities which essentially shut down the Japanese oil industry.^[4]

509th Composite Group

See: 509th Composite Group for expanded history

The 509th Composite Group was deployed overseas in the spring of 1945. The 509th was initially a part of XXI Bombardment Command based in the Marianas. By July, the bombers were established at North Field on Tinian, which had just been completed for the 313th Bombardment Wing. It was, however, under the direct operational control of the commander, Twentieth Air Force. The mission of the unit was the operational use of the Atomic Bomb.^[6]

It had only one Bombardment Squadron—the 393rd, commanded by Major Charles W. Sweeney. The 509th Composite Group was a completely self-sufficient unit, with its own engineer, material, and troop squadrons as well as its own military police unit. Since the Manhattan Project was carried out in an atmosphere of high secrecy, the vast majority of the officers and men of the 509th Composite Group were completely ignorant of its intended mission.^[6]

With the testing of the Atomic Bomb completed in the United States, the two other bombs (Little Boy, Fat Man) had arrived on Tinian on 26 July, being delivered by the USS Indianapolis (CA-35). On 24 July, a directive was sent to General Carl A. Spaatz ordering the 509th to deliver its first atomic bomb as soon as weather would permit. The Japanese cities of Hiroshima, Kokura, Niigata and Nagasaki were potential targets. President Harry S. Truman gave his final go-ahead from the Potsdam Conference on 31 July.^[6]

On 6 August the atomic attack began with a flight of three special reconnaissance F-13As (RB-29s) which took off to report the weather over the primary and secondary targets. Col. Tibbets followed in his B-29 aircraft, Enola Gay, an hour later, accompanied by two other B-29s which would observe the drop. While on the way to Japan, Major Claude Eatherly, flying Straight Flush, radioed that Hiroshima was clear for a visual bomb drop. Navy weapons expert Captain William Parsons armed the bomb while in flight, as it was deemed too dangerous to do this on the ground at North Field, lest an accident happen and the bomb go off, wiping out the entire base. At 8:15 am, the Enola Gay released Little Boy from an altitude of 31,500 feet (9,600 m). The radar fuse on the bomb had been preset to go off at an altitude of 2,000 feet (610 m) above the ground. In the ensuing explosion, yielding about 12 kilotons of TNT in explosive power, about 75,000 people were killed and 48,000 buildings were destroyed.^[6]

With no official statement from the Japanese government, there was no let-up with the conventional B-29 raids. B-29s from the 58th, 73rd, and 313th Bombardment Wings hit the Toyokawa Arsenal the next day. On the night of 7 August, the 525th Bombardment Group dropped 189 tons of mines on several different sea targets. On 8 August, the 58th, 73rd, and 313th Bomb Wings dropped incendiary bombs on targets at Yawata in the southern island of Kyūshū. At the same time, the 314th BW hit an industrial area of Tokyo. The Japanese defenses were still effective enough to down four B-29s during the Yawata raid and three at Tokyo.^[4]

Since there was still no official reaction from Japan, the Americans felt that there was no alternative but to prepare a second atomic attack. The plutonium bomb called "Fat Man" was loaded into a B-29 known as Bockscar (Martin-Omaha built B-29-35-MO serial number 44-27297, the name often spelled Bock's Car), named after its usual commander, Captain Frederick C. Bock. However, on this mission, the aircraft was flown by Major Sweeney, with Capt. Bock flying one of the observation planes. The primary target was to be the Kokura Arsenal, with the seaport city of Nagasaki as the alternative.^[6]

Bockscar took off on 9 August, with Fat Man on board. This time, the primary target of Kokura was obscured by dense smoke left over from the earlier B-29 raid on nearby Yawata, and the bombardier could not pinpoint the specified aiming point despite three separate runs. So Sweeney turned to the secondary target, Nagasaki. There were clouds over Nagasaki as well, and a couple of runs over the target had to be made before the bombardier could find an opening in the clouds. At 11:00 am, Fat Man was released from the aircraft and after a long descent, the bomb exploded. The yield was estimated at 22 kilotons of TNT. Approximately 35,000 people died at Nagasaki from the immediate blast and fire.^[6]

After releasing the bomb, Sweeney was forced to divert to Okinawa because of a problem with a fuel transfer pump, and because of the long flight with multiple bomb runs and circling for better weather. There was not even enough fuel left to fly to Iwo Jima. After refueling on Okinawa, the B-29 returned to Tinian. The Japanese Emperor ordered that the government accept the Allied terms of surrender at once. It took time for the full details to be worked out, and there was a very real danger that some elements of the Japanese military would still not accept surrender, and might attempt a military coup d'état, even against their Emperor.^[6]

In the meantime, conventional bombing of Japanese targets still continued, with a record number of 804 B-29s hitting targets in Japan on 14 August. On the morning of 15 August, the Emperor broadcast by radio his command of Japan's surrender in an address to his nation. Practically none of his subjects had never heard his voice before. All further offensive operations against Japan ceased after the Emperor's broadcast.^[4]

After that time, most of the B-29s in the Pacific were diverted to missions of mercy, dropping food and clothing to thousands of Allied prisoners of war held in Japan, China, Manchuria, and Korea. 1066 B-29s participated in 900 missions to 154 camps. Some 63,500 prisoners were provided with 4470 tons of supplies. These flights cost eight B-29s lost by accidents, with 77 crew members aboard.^[4]

The Japanese surrender was formally signed on 2 September 1945, aboard the huge battleship USS Missouri in Tokyo Bay, bringing the Pacific War to an end.