How American Air Power Helped Seal the Fate of Imperial Japan

This appeared earlier and is being reposted due to reader interest.
December 22, 2020 Topic: History Region: Asia Blog Brand: The Reboot Tags: World War IIB-29MilitaryTechnologyHitlerJapanAir ForceTokyoWarHistory

How American Air Power Helped Seal the Fate of Imperial Japan

American bombers helped crush Imperial Japanese industry and were also the plane that delivered the two atomic bombs.

After Japanese forces in China went on the offensive and threatened the Allied bases, Chennault renewed his efforts. He was supported by the new commander in China, Lt. Gen. Albert C. Wedemeyer. LeMay questioned Wedemeyer’s authority since he only commanded in China and the B-29s were in India, but Arnold agreed to the mission since he really had no other choice in view of the military situation in the region.

Incendiary Bombs on Hankow

The attack on Hankow was not the first B-29 incendiary attack of the war. Arnold had ordered experimental incendiary attacks from Saipan in November 1944, and a mission on the night of November 29 against Tokyo had met with little success. The Hankow attack was successful beyond expectations. Eighty-four B-29s were part of a more than 200-plane mission on December 18. In spite of the initial formation dropping its bombs upwind, damage to the docks and warehouses was tremendous. Intelligence estimated that 40 to 50 percent of the target had been destroyed by 38 percent of the bombs. Chennault reported that Hankow had been rendered useless as a military base.

On October 20, 1944, Brig. Gen. Emmett “Rosie” O’Donnell arrived on Saipan to open the headquarters of the 73rd Bombardment Wing, which originally had been intended to be part of Matterhorn but was switched to the Marianas when Saipan fell to the Allies. O’Donnell had been preceded by Brig. Gen. Haywood “Possum” Hansell, who arrived on Saipan on October 12 in the first B-29 to reach the islands. Hansell, a strong advocate of precision bombing, had been involved with the B-29 program from its inception and had previously served as chief of staff of Twentieth Air Force.

Hansell and O’Donnell faced a bomber shortage. The 73rd Wing’s aircraft were strung out across the Pacific all the way back to Kansas and the initially expected arrival of five planes per day had been reduced to two or three. The first mission flown by planes of the new XXI Bomber Command was against the former Japanese supply base at Truk in the Caroline Islands. Truk had originally been selected as the first target for the atomic bomb, but it had been reduced to near-uselessness after falling under attack by Navy carrier-based aircraft and B-24s of the Thirteenth Air Force.

That initial mission was a sortie of 18 B-29s in October. Four aborted, including Hansell’s command ship, thus destroying his chances to fly a combat mission in a B-29. A few days later, his successor, Brig. Gen. Lauris Norstad, invoked a regulation prohibiting the commanding general of a very heavy bombing command from flying over enemy territory.

B-29 Success Rises

Once combat operations against Japan commenced, Hansell and O’Donnell lost their authority for mission planning to Twentieth Air Force in Washington. The first target directive was the destruction of the Japanese aircraft industry, with XX Bomber Command continuing the campaign it had commenced while XXI struck targets out of range of B-29s operating from China. The city of Tokyo itself was not on the list of primary targets, although aircraft factories in outlying areas were. For propaganda effect at home, Twentieth Air Force chose to fly the first mission against the Nakajima Hikoki plant at Mushasino, a Tokyo suburb, which was the number two target on the priority list. The plant was believed to produce more than 30 percent of all Japanese combat aircraft engines, but the main reason it was chosen was so that headlines would read “TOKYO BOMBED!!!” The attack was to be carried out in daylight using precision bombing methods.

Although Hansell submitted plans for an attack in October, the aircraft delivery problem led to a postponement until November. The first B-29 over Tokyo was actually a reconnaissance version, an F-13 piloted by Captain Ralph D. Steakly. Seventeen reconnaissance missions—eight were weather observation flights—were flown over Japan before the first raid. One F-13 was lost to fighter attack on a mission to Nagoya.

Hansell’s plan, code-named San Antonio I, was predicated on intelligence estimates of Japanese fighter strength in the Tokyo area that turned out to be greatly overstated. Estimates ranged from 600 to 1,100 fighters around Tokyo alone, when in reality Japan only had 375 operational fighters to defend the entire country at the time. The attack was initially planned for early November, with Navy carrier strikes preceding the B-29s by five days. But the Navy was preoccupied with operational problems in the Philippine Sea and postponed its operations around Japan entirely.

Hansell decided to go it alone. The raid was set for November 17, but heavy rain and a wind shift led to a postponement. The rains continued for a week, but the morning of November 24 dawned clear, with winds favoring the downhill runway.

General O’Donnell led the formation off the runway with Major Robert K. Morgan, famous as pilot of the B-17 Memphis Belle, in the copilot’s seat. A total of 111 B-29s took off from Saipan, but 17 aborted and six others were unable to drop their bombs. Poor weather over Tokyo and strong jet stream winds made bombing difficult. Only 24 airplanes actually bombed the target. Results were actually better than believed. Japanese records revealed that 48 bombs struck the factory. Damage to the facilities was minor, and less than 150 casualties were reported. Nevertheless, the raid had tremendous psychological value as many of Japan’s civilian leaders realized the war was lost. They began moving production facilities underground, although none of the underground facilities had begun production by the end of the war.

Missions against aircraft industry targets continued into January, but results were poor. Weather conditions between Saipan and Japan presented major problems as cold, arctic air collided with warm Pacific air to produce thunderstorms, a virtual wall that the bombers had to penetrate on their way in and out of the target area. Actual damage to Japanese facilities was minor, although a raid on Nagoya on December 13 did significant damage to the engine factory target.

Twentieth Air Force was pressing for experimental incendiary attacks, a move that Hansell resisted to the detriment of his own future. The success of the Hankow mission on December 18 led Norstad to order a full-scale incendiary attack on Nagoya. Hansell protested the change of focus and did not fly the test mission until January 2. Three days later, Norstad arrived from the United States to inform Hansell that he was being relieved. General Curtis LeMay was brought in from the China-Burma-India Theater to replace him.

Ironically, the last mission flown under Hansell’s command was one of the best precision bombing missions of the entire war. On January 17, a formation of 73 B-29s attacked the Kawasaki plant at Aksahi with 115 tons of high explosive bombs. U.S. intelligence estimated that 38 percent of the buildings were damaged, but actual results were much greater. Japanese records revealed that the plant had been 90 percent destroyed, and Kawasaki decided to shut it down. The successful attack proved Hansell’s theories of daylight precision bombing, but knowledge of the real results came too late to save him from the chopping block.

Heavy Casualties, Inconclusive Results

LeMay’s arrival initially brought few changes. On January 23, he requested permission to attack more lightly defended targets but was advised by Norstad that while he had full latitude for target selection, an incendiary attack on Kobe would be more fruitful. LeMay realized where his bread was buttered and made plans to bomb Kobe on February 4 with an expected 157 planes. The mission was the largest of the war to date, with bombers from two wings participating for the first time. By the time the formation reached the target it had been reduced to just 69 planes. Only 129 had taken off; then aborts and other problems took a heavy toll. The formation dropped 159.2 tons of incendiaries and 13.6 of fragmentation bombs from high altitudes. Some 200 fighter attacks were reported, and one B-29 was lost while 35 suffered damage. Post-strike photos indicated major damage, and the estimates were supported by Japanese records that revealed that some 1,039 buildings had been destroyed or severely damaged. Casualties were moderate, but more than 4,000 people were left homeless.

Following the Kobe mission, the Nakajima plant at Ota, where the company was turning out its new Ki-84 “Frank” fighter, was hit. The Ki-84, a design with high-altitude capabilities, was a threat to the B-29s, which were still flying unescorted. In spite of poor bombing accuracy—only seven incendiaries and 93 high explosive bombs hit the factory—damage was substantial. The handful of incendiaries set fires that destroyed 37 buildings and 74 of the new Ki-84 fighters. Losses had been heavy, with 12 bombers shot down and 29 damaged.

Washington was still interested in a firebombing campaign, and Norstad reminded LeMay that results were still inconclusive. LeMay scheduled a massive firebombing attack on Tokyo for February 25, 1945, with more than 200 bombers participating. Out of 231 B-29s that took off from Saipan, 172 dropped 453.7 tons of incendiaries. Clouds obscured the city, and bombardiers had to release their bombs using radar, but the fires destroyed about one square mile of urban area. Japanese records reported that more than 28,000 buildings were destroyed and thousands died in the flames and from smoke inhalation.