Japanese Home Islands Bombing

YB-29 Superfortresses in flight.

On May 14, 1945 472 B-29s attacked the area in and around the Mitsubishi engine factory at Nagoya. Two nights later, another visit to Nagoya devastated another four square miles of that city. On May 23 and May 25, Tokyo was hit again. Although these two Tokyo raids had cost 43 B-29s, over 50 percent of the city had now been destroyed.

Alarmed at the increasing B-29 losses, a change of tactics was ordered. In an attempt to confuse the enemy defenses and to lure Japanese fighters into an air battle in which many of them would be destroyed, high-altitude daylight attacks were temporarily resumed. On May 29, 454 B-29s appeared over Yokohama, but this time they were escorted by P-51 Mustangs from Iwo Jima. In the resulting dogfight, 26 Japanese fighters were destroyed against the loss of four B-29s and three P-51s. 

Thereafter, the Japanese hoarded their surviving fighters for a last-ditch effort against the inevitable invasion force, and the air defense of cities became a lesser priority. By June of 1945, Japanese interceptors were seen much less frequently and the B-29s had free reign over all Japanese airspace.

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Despite widespread awareness about the vulnerability of the Japanese home islands to air attack—reinforced by the results of the Doolittle Raid on Tokyo on 18 April 1942—U.S. plans for an air war against Japan remained vague until well into 1943 because of American limitations in resources and technology.

The development of the Boeing B-29 Superfortress changed this situation. Eventually, more than 1,000 of the long-range aircraft were deployed in the Twentieth Air Force under the direct control of the Army Air Forces commander, General Henry “Hap” Arnold, subdivided into the XX and XXI Bomber Commands. Under pressure to get results from his expensive very-heavy bomber program, he fielded the new aircraft even before testing had been completed.

In June 1944, B-29s from Major General Kenneth Wolfe’s XX Bomber Command began bombing Japan from China as part of Operation MATTERHORN. The campaign was plagued by logistical problems that got worse when Japanese troops overran advanced Allied airfields in China. Arnold replaced Wolfe with the USAAF’s premier problem-solver, Major General Curtis LeMay. However, even he could not make MATTERHORN a success. Arnold’s greatest hopes for an airpower victory over Japan rested with Brigadier General Haywood “Possum” Hansell’s XXI Bomber Command, which began operations from the Mariana Islands in November 1944. Hansell was one of the architects of the precision-bombing doctrine, but his operations also had little success.

Poor facilities, faulty training, engine failures, cloud cover, and jet streams at bombing altitudes made precision methods impossible. Hansell seemed unwilling to change his tactics, however, and Arnold feared that he would lose control of the heavy bombers to Allied Pacific theater commanders without better results, so he consolidated both bomber commands in the Marianas under LeMay and relieved Hansell.

LeMay instituted new training and maintenance procedures but still failed to achieve useful results with daylight high-altitude precision attacks. He decided to resort to low-level incendiary raids at night. Although area-firebombing went against dominant Air Forces doctrine, flying at low altitude reduced engine strain, required less fuel, improved bombing concentration, avoided high winds, and took advantage of weaknesses in Japanese defenses. LeMay’s systems analysts predicted that he could set large enough fires to leap firebreaks around important industrial objectives. His first application of the new tactics, Operation MEETINGHOUSE, against Tokyo on the night of 9 March 1945, produced spectacular destruction and was the deadliest air raid of the war.

Once enough incendiaries were stockpiled, the fire raids began in earnest. Warning leaflets were also dropped, which terrorized 8 million Japanese civilians into fleeing from cities. When General Carl Spaatz arrived in July to take command of U.S. Army Strategic Air Forces in the Pacific, including the Eighth Air Force redeploying from Europe, and to coordinate strategic air operations supporting the invasion of Japan, he had a directive to shift the air campaign from cities to transportation. But there was too much momentum behind the fire raids, sustained by operational tempo, training programs, and bomb stockage.

By the time Spaatz arrived, naval carrier strikes were also hitting key industrial objectives in Japan.More important, a submarine blockade had crippled the Japanese economy, the Russians were about to attack Manchuria, and Spaatz maintained direct command over the 509th Composite Group of B-29s specially modified to carry atomic bombs. Directed by Washington to deliver these weapons as soon as possible after 3 August, Spaatz ordered the attacks on Hiroshima and Nagasaki. These different elements combined with the incendiary campaign to comprise the series of blows that produced Japanese surrender.

As with the atomic bomb, there is still debate over the effects and morality of the firebombing raids. LeMay’s bombers burned out 180 square miles of 67 cities, killed at least 300,000 people, and wounded more than 400,000. His 313th Bomb Wing also sowed 12,000 mines in ports and waterways, sinking almost 1 million tons of shipping in about four months. LeMay remained convinced that his conventional bombing could have achieved victory by itself. LeMay, his tactics, and the legacy of the atomic bombs would be a primary influence in the shaping of the new United States Air Force.

References Hansell, Haywood S. Jr. Strategic Air War Against Japan. Washington, DC: U.S. Government Printing Office, 1980.