Strategic air warfare against Japan

While the European theater air war in the Second World War was a clearly joint U.K.-U.S. effort, strategic operations in the Pacific Theater of Operations (PTO) was a solely American effort. While strategic bombing was the core of WWII strategic air warfare doctrine, there were key operational differences between the Pacific and European theaters. In Europe, the offensive counter-air process of gaining air supremacy over Europe had to proceed in concert with the strategic bombing offensive, which placed bomber crews in great danger. While in the Pacific, by the time the strategic bombing of Japan could begin, air superiority had been achieved.

Context and Issues

Army Chief of Staff George C. Marshall explained American strategy three weeks before Pearl Harbor:

"We are preparing for an offensive war against Japan, whereas the Japs believe we are preparing only to defend the Philippines. ... We have 35 Flying Fortresses already there the largest concentration anywhere in the world. Twenty more will be added next month, and 60 more in January. ... If war with the Japanese does come, we'll fight mercilessly. Flying fortresses will be dispatched immediately to set the paper cities of Japan on fire. There won't be any hesitation about bombing civilians it will be all-out."

Preparation was more complicated in the Pacific, because Japan controlled all the islands within the range U.S. bombers to Tokyo. It was suggested that perhaps suitable bases could be built in China, but this would required a very-long-range bomber for those bases, which the U.S. was only then just planning. The B-29, therefore, was ordered into production. Closer and more secure bases could be built in the Mariana Islands (Saipan, Guam, Tinian, and others), but these would have to be taken from the Japanese and were not invaded until June 1944.

Technology

Aircraft

Strategic aircraft capable of attacking the Japanese Home Islands

Country and aircraft	Theater	Features and liabilities
U.S. B-29 Superfortress	Pacific	Heavy bombload, very long range

Allied land-based aircraft supporting the gaining of air bases

Country and aircraft	Features and liabilities	Effectiveness
U.S. B-17 Flying Fortress	Light bombload in its class, strong defense. Bombsight could not hit moving targets	Low; insufficient bombload and range even against island targets
U.S. B-24 Liberator	Moderate bombload, long range very important	Good
U.S. B-25 Mitchell	Medium bomber	Lighter than B-26, made Doolittle Raid
U.S. B-24 Liberator (bomber)	Moderate bombload, long range very important	Excellent, especially low-level anti-shipping versions
U.S. P-38 Lightning	Long range with reliability of second engine	Excellent
U.S. B-29 Superfortress	Heavy bombload, very long range	Only aircraft to hit home islands

Basing

When war began the Philippine airbases were quickly lost. American strategy then focused on getting forward airbases close enough to Japan to use the very-long-range B-29 bomber, then in development. At first the B-29's were stationed in China and made raids in 1944; the logistics made China an impossible base. Finally, in summer 1944, the U.S. won the Battle of the Philippine Sea and captured islands that were in range.

The Marianas, captured in June 1944, gave a close secure base, and the B-29 gave the Americans the weapon they needed. Computerized fire-control mechanisms made its 13 guns exceptionally lethal against fighters.

Targeting

The flamability of Japan's large cities, and the concentration of munitions production there, made strategic bombing the war-winning weapon. Two months before Pearl Harbor Chinese leader Chiang Kai-shek proposed sending Flying Fortresses over Tokyo and Osaka, "whose paper and bamboo houses would go up in smoke if subjected to bombing raids." Massive efforts (costing $4.5 billion dollars) to establish air bases in China failed. Hundreds of thousands of Chinese peasants broke rocks with little hammers and dug drainage ditches by hand. Shipping supplies around the world to equip the bases was almost impossible, and when some bases were ready in 1944 the Japanese Army simply moved overland and captured them.

However, the systematic raids that began in June, 1944, were unsatisfactory, because the AAF had learned too much in Europe; it overemphasized self-defense. An additional technical problem was that high-altitude winds were much greater over Japan than Germany, for which the Norden bombsight could not compensate.

Japan's stocks of guns, shells, explosives, and other military supplies were thoroughly protected in dispersed or underground storage depots, and were not vulnerable to air attack. The bombing affected long-term factors of production. Physical damage to factories, plus decreases due to dispersal forced by the threat of further physical damage, reduced physical productive capacity by roughly the following percentages of pre-attack plant capacity:

• oil refineries, 83%
• aircraft engine plants, 75%
• air-frame plants, 60%
• electronics and communication equipment plants, 70%
• army ordnance plants, 30%
• naval ordnance plants, 28%
• merchant and naval shipyards, 15%
• aluminum, 35%
• steel, 15%
• chemicals, 10%.

Munitions output plummeted, and by July, 1945, Japan no longer had an industrial base. The problem was that it still had an Army, which was not based in the cities, and was largely undamaged by the raids. The Army had ammunition but was short of food and gasoline; as Iwo Jima and Okinawa proved, it was capable of ferocious resistance.

Offensive operations

To avoid constant friction between MacArthur and Nimitz, Arnold retained personal charge of the strategic bomber force. The first field commander, Haywood S. Hansell, was not satisfactory to Arnold. Arnold offered Hansell the job of LeMay's deputy, but he declined.

In early 1945, LeMay ordered a radical change in tactics: remove the machine guns and gunners, fly in low at night. (Much fuel was used to get to 30,000 feet; it could now be replaced with more bombs.) The Japanese radar, fighter, and anti-aircraft systems were so ineffective that they could not hit the bombers. Fires raged through the cities, and millions of civilians fled to the mountains. Tokyo was hit repeatedly, and suffered a fire storm in March that killed 83,000. On June 5, 51,000 buildings in four miles of Kobe were burned out by 473 B-29s; Japanese opposition was fierce, as 11 B-29s went down and 176 were damaged. Osaka, where one-sixth of the Empire's munitions were made, was hit by 1,733 tons of incendiaries dropped by 247 B-29s. A firestorm burned out 8.1 square miles, including 135,000 houses; 4,000 died. The police reported: Although damage to big factories was slight, approximately one-fourth of some 4,000 lesser factories, which operated hand-in-hand with the big factories, were completely destroyed by fire.... Moreover, owing to the rising fear of air attacks, workers in general were reluctant to work in the factories, and the attendance fluctuated as much as 50 percent.

Defense

In evaluating the strategic bombing campaigns it is important to keep in mind what the targets were. The AAF (and the RAF) concentrated on the largest 75 to 100 cities in Germany and Japan.

Some raids caused "firestorms," notably Hamburg and Kassel in 1943, Dresden and Tokyo in 1945. Firestorms were very hard to start; they occurred in unpredictable situations when a number of scattered fires suddenly combined into a tornado-like inferno which sucked up all the oxygen (including the oxygen in underground shelters). At Hamburg 40,000 people suffocated inside shelters. Tens of thousands died in Dresden, but the railway yards, munitions factories and military bases were mostly undamaged. At Hamburg, full factory production resumed in a matter of weeks, but upwards of a million civilians fled the city.

MacArthur, however, refused to allow bombing of Manila in 1945 because the Filipinos were American subjects.

Primary responsibility for saving the lives of people in the cities was held by the defending government, not by the attacking one according the US Air Force then (and now). Every government did in fact promote civil defense by installing sirens, building bomb shelters, teaching first-aid, assigning fire-fighters and rescue workers, establishing aid stations and support agencies, and training city dwellers on what to do when a raid was imminent. In Japan, total mobilization had been declared as early as 1938 (when Japan was fighting China): "We must mobilize our entire resources, both physical and spiritual; it is not enough merely to provide sufficient munitions."Civilians were more tightly organized on behalf of the state than in any other nation, and American policy makers concluded there were no peaceable civilians in Japan. The AAF policy said that deliberate killing of innocent civilians was immoral, but that in Germany and Japan all workers "voluntary or involuntary" were assisting the enemy and should accept the risks "which must be the lot of any individual who participates directly in the war effort of a belligerent nation."

Dispersal of critical installations

For the German theater, Speer figured out the antidote to air raids in 1943-- disperse critical factories outside the major cities. With railroad yards hit every week, it took longer and longer for parts to reach underground assembly factories, and it became more and more difficult to move the final product to the front lines.

The Japanese built airplane components in thousands of small shops scattered about their major cities; they did not use their small towns and villages. The U.S. Air Force answered the dispersion by burning out entire large cities (while avoiding the small towns and villages.)

Strategic bombing doctrine had always held with enough pounding, enemy morale would collapse and they would be forced to surrender. That is indeed what happened with Japan. The Germans surrendered only after Berlin was captured, but the ability to resist invasion had been blasted away by the Allied bombings that Germany was helpless to stop. The bottom line regarding strategic bombing in World War Two is that it was the only way a total war could be fought and won. The alternatives were compromise with the Nazis and Japanese, or invasions that would have killed far more people in Japan (and did kill far more Germans than the bombings did).

Active air defense

When the B-29s attacked from high altitude, they were above the range of Japanese anti-aircraft artillery and most fighters. Fighters, if stripped of all possible weight including guns and ammunition, could reach them with suicide ramming attacks. These tactics were sufficiently effective, along with unexpected problems in bombing due to high-altitude winds, that LeMay switched to low-altitude night bombing.

The Japanese had fairly poor early warning radar and few radar-guided antiaircraft guns. At low level, radar guidance was a virtual necessity to hit bombers. Further, after Iwo Jima was taken, U.S. fighters could escort the bombers.