June, 1944: Superfortress Bombing of Japan Summary

  • Last updated on November 11, 2022

The Doolittle raid against Tokyo on April 18, 1942, was the first air raid by United States bombers on the Japanese home islands and the only one for the next two years. The rapid Japanese advance in the Pacific and the Japanese hold on the Asian mainland drove U.S. forces from any bases close enough to carry out air raids on Japan. The available heavy bombers, the B-17 Flying Fortress and the B-24 Liberator, did not have adequate range. The B-29 Superfortress, however, brought to bear new technology that made possible a devastating strategic bombing campaign against the Japanese home islands.

The Doolittle raid against Tokyo on April 18, 1942, was the first air raid by United States bombers on the Japanese home islands and the only one for the next two years. The rapid Japanese advance in the Pacific and the Japanese hold on the Asian mainland drove U.S. forces from any bases close enough to carry out air raids on Japan. The available heavy bombers, the B-17 Flying Fortress and the B-24 Liberator, did not have adequate range. The B-29 Superfortress, however, brought to bear new technology that made possible a devastating strategic bombing campaign against the Japanese home islands.

B-29’s on a bombing run over Yokohama, Japan. (National Archives)

The B-29 Bomber

The Army had shown interest in the new long-range, high-altitude bomber that the Boeing Company had begun to develop in 1938. Although the prototype, the XB-29, was not test-flown until September 21, 1942, the Air Corps had already ordered 250 planes from Boeing, which built an entire new plant to produce the new bomber exclusively. Far larger than the B-17, the Superfortress measured 99 feet in length, with a wing span of 141 feet. It weighed more than sixty tons fully loaded and had a top speed of up to 375 miles per hour. Powered by four twenty-two-hundred-horsepower Wright Duplex Cyclone engines, it had a combat radius of sixteen hundred miles fully loaded. Three separate pressurized compartments meant that its crew of eleven could cruise at the plane’s service ceiling of 31,800 feet without needing oxygen masks. The aircraft was armed with twelve .50-caliber machine guns, or ten machine guns and a 20-millimeter cannon, all mounted in power-driven turrets. Under ideal conditions, it could carry a bomb load of ten tons.

Plans by the Air Force for the plane’s use had taken various forms, including its commitment in Europe. By the time significant numbers of the planes could be ready, however, British and U.S. bombers flying from England had made the B-29 less than essential for the war against Germany. By the end of 1943, Air Force chief General H. “Hap” Arnold, was committed to its use against Japan. United States air bases in the Aleutian Islands, however, were too far from Japan. The islands in the Mariana group that could provide bases (Saipan, Tinian, and Guam) were not projected to be in U.S. hands until the winter of 1944. Thus, Air Force planners, wanting to get the new Superfortresses into operation as soon as possible, looked to China.

The U.S. Plan

On Arnold’s orders, Brigadier General Kenneth B. Wolfe drew up a plan. Submitted to the Air Force chief on October 11, 1943, Wolfe’s plan called for basing the new B-29’s in India and staging them through fields in China. Approved by Arnold, the plan then went to President Franklin D. Roosevelt. Desiring to do something for China and fearing that China’s leader, Chiang Kai-shek, might quit the war if he did not receive some tangible help against the Japanese, Roosevelt proved a receptive audience and approved the plan, known as Operation Matterhorn, in November, 1943.

The idea of an independent, powerful, strategic bombing force had long been a dream of U.S. flyers. Supplying itself with all the necessities of war, this command could, it was believed, bludgeon any enemy into surrender by strategic bombing without the necessity of invasion. Perhaps the Superfortress was the weapon.

While the Superfortress bombing raids were being conducted, the United States attacked Japanese cities with smaller planes launched from aircraft carriers. Here, gunners on the carrier USS Hornet shell Japanese positions from the sea, while their own aircraft are bombing Tokyo, in February, 1945. (National Archives)

Having committed itself to a strategic bombing campaign against the Japanese home islands, in April, 1944, the United States Joint Chiefs of Staff established a special organization, the Twentieth Air Force, to direct all B-29 operations. General Arnold, acting as executive agent of the Joint Chiefs of Staff, was selected to command this new force and given control over the deployment of the Superfortresses. Neither the British commander in the area, Lord Louis Mountbatten, nor U.S. Army commander Lieutenant General Joseph W. Stilwell exercised any authority over the deployment and use of the B-29’s in the China-Burma-India theater of operations, except in an emergency. However, they would see a significant amount of the very limited tonnage that was flown over the Hump into China diverted to the B-29 bases at Chengtu.

Implementation of Operation Matterhorn was entrusted to Wolfe’s Twentieth Bomber Command, which originally was made up of the Fifty-eighth and the Seventy-third Bombardment Wings. The Seventy-third was detached in April, 1944, to go to the Mariana Islands, whose date of capture had been advanced to June, 1944. A wing contained 112 bombers plus replacement ships, and slightly more than three thousand officers and eight thousand enlisted men. Support, service, and engineering personnel brought the total strength of the Twentieth Bomber Command to approximately twenty thousand troops.

Because all supplies for Chinese bases had to be flown in, stockpiling was difficult. B-29s from India had to fly seven round trips to bring enough gasoline and other necessities to make possible one mission over Japan. With the loss of the Seventy-third Wing, the Fifty-eighth Wing could not supply itself for raids of one hundred planes or more, the hoped-for number, more than a few times each month. This, combined with the high rate of engine failure, the loss of planes because of inexperienced crews, and the other faults to be expected in a new weapon meant that the first raid on Japan could not be launched until June 15, 1944.

The Army Air Force’s (AAF) Committee of Operations analysts had suggested that an appropriate strategic target for B-29s would be the coke ovens that supplied Japan’s steel mills. Consequently, the first strike was directed against the coke ovens of the Imperial Iron and Steel Works at Yawata. Located on the island of Kyushu, at the edge of the bomber’s combat range, the Yawata plant produced 24 percent of Japan’s rolled steel and was considered the most important target in the Japanese steel industry.

The Raids Begin

Beginning on June 13, ninety-two planes left the Bengal fields in India, seventy-nine of which reached the Chengtu bases. Each came loaded with two tons of five-hundred-pound bombs and needed only to refuel in China. Commanders in Washington, D.C., who had picked the target, ordered a night mission with bombs to be dropped from between eight thousand and eighteen thousand feet. On June 15, the same day that Marines went ashore on Saipan, sixty-eight planes, led by Wing Commander Brigadier General LaVerne “Blondie” Saunders, left the fields. Four were forced back by engine trouble, and one crashed immediately after take-off. Forty-seven Superfortresses bombed Yawata that night, thirty-two using radar because of an effective blackout of the city compounded by haze and smoke. The other planes did not make it over Yawata for a variety of reasons, most of them mechanical. Six planes were lost, one to enemy fighters on the return trip. Fighter opposition over the target and antiaircraft fire had been light.

Photo reconnaissance showed little damage, the only significant hit being on a power station thirty-seven hundred feet from the coke ovens. This was not a massive fire-bomb raid of the type that would begin in March, 1945, from the Mariana Islands. The AAF was still concentrating on high-altitude, precision bombing. The Fifty-eighth Wing averaged two raids a month until March, 1945, when it was moved to Saipan. Operating under a very difficult logistical situation, Operation Matterhorn had been a stimulant for Chinese morale and had provided a necessary shakedown for the new bombers and crews. Matterhorn was not a success, nor was the first raid on Japan; but both presaged a more destructive future for the Superfortress.

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