马特霍恩作战

計劃

馬特霍恩作戰計劃最初是在1943年1月的卡薩布蘭卡會議上被醞釀。美英聯合參謀部於1943年8月在魁北克召開會議，決定在中太平洋採取奪占馬里亞納群島的作戰。不僅因為馬里亞納群島靠近東京，而且容易補給與防衛。1943年9月，美英聯合參謀部得出結論，在中國部署B-29轟炸機必須通過駝峰航線維持孤立的補給，這將招致後勤上的極大困難。但富蘭克林·羅斯福總統堅持認為從中國轟炸日本能更快縮短戰爭進程。1943年底的開羅會議，羅斯福總統向蔣介石許諾將在中國部署戰略轟炸機。亨利·阿諾德支持羅斯福總統的決定，認為中國的轟炸基地是在沒有控制馬里亞納群島之前的應急辦法。
馬特霍恩作戰計劃由Kenneth B. Wolfe准將於1943年10月制定，由第20轟炸航空隊實施，代號「夕陽」（Setting Sun）。該計劃是基於約瑟夫·史迪威的「暮光」（Twilight）計劃。B-29的主基地設在印度，在中國開設前進基地並由駝峰航線的C-109運油機、20架C-87運輸機、3架C-46運輸機組成的支援中隊維持補給。夕陽計劃原定把前進基地設在廣西。但由於豫湘桂會戰失敗，最終把B-29基地設在了成都。 最初計劃由2,000架C-109支援在中國部署10個大隊400架B-29，但由於馬里亞納群島分擔了戰略轟炸任務，最終只把218架B-26轟炸機改裝為C-109運油機。
阿諾德五星上將於1943年10月12日批准了「夕陽」計劃並通過馬歇爾將軍提交給總統與參謀長聯席會議。當時這是唯一的轟炸日本的作戰計劃。羅斯福總統不滿該計劃於1944年6月1日正式開始實施，而不是他向蔣介石保證的1944年1月1日。但羅斯福批准該計劃將實施一整年。
B-29轟炸機的作戰半徑達到1,500英里（2,400公里），執行了轟炸日本的90%的任務。 

已隱藏部分未翻譯部分，歡迎參與翻譯。

Ichi-Go and the first "fire raid"

The former European theater bomber commander continued to experiment with new technologies and tactics and soon imported to China the incendiary weapons being used by the British against Germany. In late 1944,  a Japanese offensive (codenamed Operation Ichi-Go) in China probed toward the B–29 and Air Transport Command bases around Chengdu and Kunming. To slow the enemy advance, Maj. Gen. Claire L. Chennault of the Fourteenth Air Force asked for raids on Japanese supplies at Hankow, and the Joint Chiefs directed LeMay to hit the city with firebombs. On December 18, LeMay launched the fire raid, sending eighty-four B–29s in at medium altitude with five hundred tons of incendiary bombs. The attack left Hankow burning for three days, proving the effectiveness of incendiary weapons against the predominantly wooden architecture of the Far East.
By late 1944, American bombers were raiding Japan from the recently captured Marianas, making operations from the vulnerable and logistically impractical China bases unnecessary. In January 1945, the XX Bomber Command abandoned its bases in China and concentrated 58th Bomb Wing resources in India. The transfer signaled the end of Matterhorn. During the same month, LeMay moved to the Marianas, leaving command of the XX Bomber Command in India to Brig. Gen. Roger M. Ramey. Between January and March, Ramey’s B–29s assisted Mountbatten in the South-East Asian theatre, supporting British and Indian ground forces in Burma by targeting rail and port facilities in Indochina, Thailand, and Burma. More distant targets included refineries and airfields in Singapore, Malaya, as well as Palembang and other locations in the Netherlands East Indies. The 58th, the only operational wing of the XX Bomber Command, remained in India until the end of March 1945, when it moved to the Marianas to join the XXI Bomber Command.
XX Bomber Command stopped being an operational command at the end of March 1945 when the 58th Bomb Wing moved from India to the Marianas and control of the wing passed to the XXI Bomber Command.

Assessment

The American Bomber Summary Survey states that "Approximately 800 tons of bombs were dropped by China-based B-29s on Japanese home island targets from June 1944 to January 1945. These raids were of insufficient weight and accuracy to produce significant results." XX Bomber Command had failed to achieve the strategic objectives that the planners had intended for Operation Matterhorn, largely because of logistical problems, the bomber’s mechanical difficulties, the vulnerability of Chinese staging bases (see Operation Ichi-Go), and the extreme range required to reach key Japanese cities. Although the B–29s achieved some success when diverted to support Chiang Kai-shek’s forces in China, MacArthur’s offensives in the Philippines, and Mountbatten’s efforts in the Burma Campaign, they generally accomplished little more than the B-17 Flying Fortresses and B-24 Liberators assigned to the Fourteenth, Fifth, Thirteenth, and Tenth Air Forces.
Chennault considered the Twentieth Air Force a liability and thought that its supplies of fuel and bombs could have been more profitably used by his Fourteenth Air Force. The XX Bomber Command consumed almost 15 percent of the Hump airlift tonnage per month during Matterhorn. Lt. Gen. Albert C. Wedemeyer, who replaced Lt. Gen. Joseph W. Stilwell as American senior commander in the China theater, agreed with Chennault. The two were happy to see the B–29s leave China and India. Yet, despite those objections, Matterhorn did benefit the Allied effort. Using the China bases bolstered Chinese morale and, more important, it allowed the strategic bombing of Japan to begin six months before bases were available in the Marianas. The Matterhorn raids against the Japanese home islands also demonstrated the B–29’s effectiveness against Japanese fighters and anti-aircraft artillery. Operations from the Marianas would profit from the streamlined organization and improved tactics developed on the Asian mainland.

指揮架構

General Arnold retained personal command of the Twentieth Air Force – to avoid diversion of assets from the B-29 effort against Japan, particularly by Admiral Nimitz, who was given command authority over all efforts in the Central Pacific – with Brigadier General Haywood S. Hansell as chief of staff (and later commander of XXI Bomber Command). Tentative plans called for an operational force of 48 B-29 groups, numbering between 1,000 and 1,500 B-29s, to be deployed in four bomber commands (the XX BC of 4 groups in India-China, the XXI BC of 16 groups in the Marianas, the XXII BC of 24 groups in the Philippines and Okinawa, and the XXIII BC of 4 groups in the Aleutians).
Original plans for XX Bomber Command to employ two combat wings in China (the 58th and 73rd Combat Bomb Wings) were changed on 2 March 1944 when limited numbers of operational B-29s resulted in only the 58th CBW assigned. There, after poor bombing results, and as developing operations deemed the original complex organization unnecessary, it was deemed a redundant level of command and its four groups moved to Guam in April 1945 as part of XXI Bomber Command.
The bases in China were part of the China Burma India Theater of World War II for administrative purposes.  The commander of the XX Bomber Command had no control over stations, bases, units, and personnel not directly assigned to him, and none over shipping and other logistic support essential to the operation.  However the Commander-in-Chief of the XX Bomber Command reported directly to the JCS in Washington and was not under SEAC operational control like the rest of the personnel in the CBI.
The British planning to deploy their new Very Long Range Bomber Force (of about 22 squadrons) to the Far East for final operations against the Japanese, proposed that Twentieth Air Force be controlled by the Combined Chiefs, as had the air forces in Europe, but when the Americans rejected the proposal (because the forces involved were overwhelmingly American), the British dropped the issue.