Over the Hump to Matterhorn

In April 1944, the Joint Chiefs of Staff approved Operation Matterhorn, a plan for bombing Japanese strategic targets with B–29s based in China. A committee of operations analysts who advised the Joint Chiefs of Staff and the Twentieth Air Force on targets recommended Superfortress attacks on coke ovens and steel factories in Manchuria and Kyushu. Shutting down these key industries would severely cripple the enemy’s war effort. Also on the target list were important enemy harbor facilities and aircraft factories. Wolfe launched the first B–29 Superfortress combat mission on June 5, 1944, against Japanese railroad facilities at Bangkok, Thailand, about 1,000 miles away. Of the ninety-eight bombers that took off from India, seventy-seven hit their targets, dropping 368 tons of bombs. Encouraged by the results, XX Bomber Command prepared for the first raids against Japan. 

Ten days later, sixty-eight Superfortresses took off at night from staging bases at Chengtu to bomb the Imperial Iron and Steel Works at Yawata on Kyushu, more than 1,500 miles away. The June 15, 1944, mission—the first raid on the Japanese home islands since the Doolittle attack of April 1942—marked the beginning of the strategic bombardment campaign against Japan. Like the Doolittle raid, it achieved little physical destruc-tion. Only forty-seven of the sixty-eight B–29s airborne hit the target area; four aborted with mechanical problems, four crashed, six jettisoned their bombs because of mechanical difficulties, and others bombed secondary targets or targets of opportunity. Only one B–29 was lost to enemy aircraft. 

The second full-scale strike did not occur until July 7, 1944. By then, Arnold, impatient with Wolfe’s progress, had replaced him temporarily with Brig. Gen. LaVern G. Saunders, until Maj. Gen. Curtis E. LeMay could arrive from Europe to assume permanent command. Unfortunately, the three-week delay between the first and second missions reflected serious problems that prevented a sustained strategic bombing campaign from China against Japan. Each B–29 mission consumed tremendous quantities of fuel and bombs, which had to be shuttled from India to the China bases over the Himalayas, the world’s highest mountain range. For every Superfortress combat mission, the command flew an average of six B–29 round-trip cargo missions over the Hump. Even after the Air Transport Command took over the logistical supply of the B–29 bases in China at the end of 1944, enough fuel and bombs never seemed to reach Chengtu. 

Range presented another problem. Tokyo, in eastern Honshu, lay more than 2,000 miles from the Chinese staging bases, out of reach of the B–29s. Kyushu, in southwestern Japan, was the only one of the major home islands within the 1,600-mile combat radius of the Superfortress. 

And the very heavy bomber still suffered mechanical problems that grounded some aircraft and forced others to turn back before dropping their bombs. Even those B–29s that reached the target area often had difficulty in hitting the objective, partly because of extensive cloud cover or high winds. Larger formations could have helped compensate for inaccurate bombing, but Saunders did not have enough B–29s to dispatch large formations. Also, the Twentieth Air Force periodically diverted the Superfortresses from strategic targets to support theater commanders in Southeast Asia and the southwestern Pacific. For these reasons, the XX Bomber Command and the B–29s largely failed to fulfill their strategic promise. 

On August 20, LeMay arrived to breathe new energy into the XX Bomber Command. The former Eighth Air Force bomber pilot and group commander had achieved remarkable success with strategic bombing operations in Europe, testing new concepts such as stagger formations, the combat box, and straight-and-level bombing runs. The youngest two-star general in the AAF had also revised tactics, tightened and expanded formations, and enhanced training for greater bombing precision. He inaugurated a lead-crew training school so that formations could learn to drop as a unit on cue from the airplane designated as the lead ship. 

During his first two months at XX Bomber Command, LeMay had little more success than Wolfe or Saunders. The command continued to average only about one sortie a month per airplane against Japan’s home islands. When MacArthur invaded the Philippines in October 1944, LeMay diverted his B-29s from bombing Japanese steel facilities to striking enemy aircraft factories and bases in Formosa, Kyushu, and Manchuria.

 Meanwhile, LeMay gained the support of Communist leader Mao Tse-tung, who controlled parts of northern China. Willing to help against a common enemy, Mao agreed to assist downed American airmen and to locate in northern China a weather station that would provide better forecasts for the XX Bomber Command’s raids on the Japanese in Manchuria and Kyushu. Hoping to gain American recognition of his own regime, Mao suggested that the Americans set up B–29 bases in northern China like those in Chi-ang Kai-shek’s area of control in southern China. LeMay declined, however, because he found it difficult enough to supply the airfields at Chengtu. 

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 in China probed toward the B–29 and Air Transport Command bases around Chengtu 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 southeastern Asia, 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, and the 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. 

At the end of the war, the U.S. Strategic Bombing Survey delicately judged the B–29 operations against Japan from China to be “not decisive.” Matterhorn had failed to achieve its strategic objectives, largely because of logistical problems, the bomber’s mechanical difficulties, the vulnerability of Chinese staging bases, 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 Burma, they generally accomplished little more than the B–17s and B–24s 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 al-most 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 antiaircraft artillery. Operations from the Marianas would profit from the streamlined organization and improved tactics developed on the Asian mainland.