When the United States entered World War II on December 8, 1941, it possessed no aircraft capable of reaching the Japanese mainland from land bases. The nearest friendly territory (discounting Siberia, from which the Soviet Union had banned any flights) lay 1,600 miles away in central China, well beyond the operating radius of existing Boeing B-17s and Consolidated B-24s.

On April 18, 1942, an audacious raid on Tokyo, Nagoya, Kobe and Yokohama was launched when Lt. Col. James H. Doolittle led a flight of 16 North American B-25s from the flight deck of the carrier Hornet. That sortie, a one-time effort that resulted in little damage to the widely dispersed targets, was intended primarily as a boost to sagging American morale and as an embarrassment to the Japanese general staff. Carrier-borne attacks against the Japanese Home Islands would not occur again for nearly three years.

The original concept behind the Boeing B-29 was "hemispheric defense," that is, a very long-range bomber that could operate out of bases within U.S. territories. However, in 1940, amid fears that America would ultimately be drawn into the conflict then raging in Europe, the War Department drafted a contingency plan to use the proposed B-29 to bomb Germany from bases in either Britain or North Africa. Two events then intervened that irrevocably set the B-29 on a course for the Far East. First, after the dust from the Japanese attack on Pearl Harbor settled, President Franklin D. Roosevelt and the Joint Chiefs of Staff decided that America’s primary war effort would be focused on defeating Germany first. In terms of land-based heavy bombardment, this meant that most of the current production four-engine bombers, B-17s and B-24s, would be earmarked for combat missions in the European Theater of Operations. Second, the president believed it was imperative to make a gesture to assure the Chinese leader, Generalissimo Chiang Kai-shek, that the United States was prepared to stop the Japanese from taking over all of China.

The first B-29 prototype, meanwhile, flew on September 21, 1942, and the type was anticipated to be combat-ready by late 1943. The airplane itself was a technological triumph, able to cruise at speeds near 300 mph and capable of carrying 5,000 pounds of bombs in the rarefied air above 30,000 feet (or twice that weight at lower altitudes) while conveying its bombload to a target more than 1,600 miles away. But the B-29 was also the most complex machine the American aircraft industry had ever tried to produce, and the giant plane had big problems, the most persistent and dangerous of which involved engine fires linked to the cooling of the new Wright R-3350 engines.

The die was cast during the Casablanca conference in January 1943, when Roosevelt, in spite of serious reservations expressed by the Joint Chiefs, informed Chiang Kai-shek that he would send a large force of bombers to strike at Japan from China. Although the president did not specifically mention B-29s, it was certainly the only type of U.S. aircraft then capable of such a mission.

Three issues were central to planning bomber operations out of China: command and control of the B-29s once they were deployed overseas, resupply and maintenance support for a large bomber force, and construction of bases for combat operations. Command of the China-Burma-India (CBI) Theater was essentially divided three ways. British Lord Louis Mountbatten commanded the India-Burma area, while Lt. Gen. Joseph Stilwell was the U.S. theater commander in China, also serving as Chiang’s chief of staff -- and then there was Chiang Kai-shek himself. Added to that was Maj. Gen. Claire Chennault, commander of the Fourteenth Air Force in China, who had his own ideas about the employment of the bomber force.

Logistics posed an enormous problem. The Japanese occupied Burma between China and India and controlled the entire Chinese coast, which precluded resupply by land or sea. Munitions, spares, fuel and everything else needed to support operations would have to be flown in from India over "the Hump," the Himalaya Mountains. And then there was the problem of airfields -- the B-29s could not operate off hastily prepared airstrips covered with pierced-steel matting. The 120,000-pound bombers would need hard-surface runways more than a mile long.

At the Quadrant Conference at Quebec, Canada, in August 1943, U.S. Army Air Forces chief General Henry H. "Hap" Arnold submitted a detailed plan under which the newly activated 58th Bomb Wing (Very Heavy) would reach the CBI Theater by the end of 1943 and shortly after begin offensive operations against the Japanese Home Islands. Brigadier General Kenneth Wolfe, whom Arnold appointed to command the new unit and plan the operations, had earlier been responsible for B-29 development and production at Wright Field, then the center for U.S. Army Air Forces aircraft testing and evaluation. Arnold’s plan originally envisioned that the B-29s would be permanently based in south-central China and be resupplied by air from India. Although Roosevelt liked the plan, General Stilwell contended that maintaining all B-29 operations within China would not be practical because the supply lines were too long. He suggested instead that the China bases be used only as a forward staging area, while complex base facilities would remain in eastern India. Even though the Joint Chiefs were skeptical about the value of staging any B-29 operations out of China, Stilwell’s recommendations were reluctantly approved, and the Chengdu area, 175 miles west of Chunking, was selected as the site for the forward bases. The plan as approved would be dubbed "Matterhorn," the Allied code name for the strategic air offensive against Japan. Arnold and his field commanders would soon find themselves faced with an uphill struggle to resolve huge operational challenges with the ambitious offensive.

When it came to delineating who would control the B-29s, Arnold set up an unprecedented organizational structure that bypassed the operational authority of the theater commanders. The XX Bomber Command, to which the 58th Bomb Wing was attached, would take its combat orders from the Joint Chiefs, with executive control vested in Arnold himself -- in effect, an independent air force within the Army Air Forces. Arnold had embraced the notion of an "independent strategic striking force" as far back as the 1920s, when he worked with Brig. Gen. William L. "Billy" Mitchell. But he was more immediately concerned with the rivalries within the CBI and also those between U.S. Army General Douglas MacArthur and U.S. Navy Admiral Chester Nimitz in the southwest Pacific and Pacific theaters. Months later, this organization would evolve into the newly created Twentieth Air Force, which would direct B-29 combat operations throughout the war and serve as a template for the postwar independent U.S. Air Force.

In November 1943 the British agreed to provide operational bases around Calcutta, India, and Chiang Kai-shek started construction of five forward air bases around Chengdu. Incredibly, the runways on the Chinese bases would be built entirely with manual labor, with as many as 700,000 coolies working at a single site.