|Strategic bombing during World War II|
|Part of World War II|
B-24 "Sandman" on a bomb run over the Astra Romana refinery in Ploieşti, Romania, during Operation Tidal Wave.
| United Kingdom
| Nazi Germany
Empire of Japan
| Charles Portal
| Hermann Göring
|Casualties and losses|
|60,595 British civilians
160,000 airmen (Europe)
|305,000-600,000 German civilians
330,000-500,000 Japanese civilians.
Strategic bombing during World War II is a term which refers to all aerial bombardment of a strategic nature between 1939 and 1945 involving any nations engaged in World War II. This includes the bombing of military forces, railways, harbors, cities (civilian areas), and industrial areas.
In 1939, Germany invaded Poland and the Luftwaffe (German air force) began providing tactical support to the German Army. The Luftwaffe also began eliminating strategic objectives and bombing cities in Poland. France and the United Kingdom declared war on Germany and the UK's Royal Air Force began attacking German warships along the German coast with the North Sea. Meanwhile, the German bombing of Poland became an indiscriminate and unrestricted aerial bombardment campaign.
As the war continued to expand, bombing by both the Axis and Allied powers increased significantly. Military and industrial installations were targeted, but so were cities and civilian populations. Targeting cities and civilians was viewed as a psychological weapon to break the enemy's will to fight. From 1940–1941, Germany used this weapon in its Blitz campaign against the UK. From 1940 onward, the intensity of the British bombing campaign against Germany became less restrictive, increasingly targeting industrial sites and eventually, civilian areas. By 1943, the United States had significantly reinforced these efforts. The controversial firebombings of Hamburg (1943), Dresden (1945) and other German cities followed. The attack on Dresden killed at least 24,000 people, nearly half the number of those killed in the entire Blitz campaign. Nevertheless, RAF Bomber Command had a limited effect on German industrial production, and was no more successful at breaking Germany's will to fight than the Luftwaffe was at breaking Britain's.
In the Pacific theatre, the Japanese bombed Chongqing repeatedly until 1943. U.S. strategic bombing of the Japanese Empire began in earnest in October 1944. Earlier, small-scale attacks by the U.S. out of China had been hampered by task of delivering supplies over the Himalaya foothills (known as "The Hump"), as well as by enormous Chinese graft.. Missions out of Saipan escalated into widespread fire-bombing, which culminated in the 1945 atomic bombings of Hiroshima and Nagasaki and the Japanese surrender six days later.
The Hague Conventions, which address the codes of wartime conduct on land and at sea, were adopted before the rise of air power. Despite repeated diplomatic attempts to update international humanitarian law to include aerial warfare, it was not updated before the outbreak of World War II. The absence of specific international humanitarian law did not mean aerial warfare was not covered under the laws of war, but rather that there was no general agreement of how to interpret those laws.
When the war began on 1 September 1939, Franklin D. Roosevelt, President of the then-neutral United States, issued an appeal to the major belligerents to confine their air raids to military targets. The French and the British agreed to abide by the request which included the provision "that these same rules of warfare will be scrupulously observed by all of their opponents". Germany also agreed to abide by Roosevelt's request and explained their bombing of Warsaw as within the agreement because it was a fortified city—Germany did not have a policy of targeting enemy civilians as part of their doctrine prior to World War II.
The United Kingdom's policy was formulated on 31 August 1939: if Germany initiated unrestricted air action, the United Kingdom "should attack objectives vital to Germany's war effort, and in particular her oil resources". If Germany confined attacks to purely military targets, the RAF should "launch an attack on the German fleet at Wilhelmshaven" and "attack warships at sea when found within range". The government communicated to their French allies the intention "not to initiate air action which might involve the risk of civilian casualties"
While it was acknowledged bombing Germany would cause civilian casualties, the British government renounced deliberate bombing of civilian property, outside combat zones, as a military tactic. On 15 May, the day after the Rotterdam Blitz, the British government met and authorised "Bomber Command to carry out attacks on suitable military objectives, (including marshalling yards and oil refineries) in the Ruhr as well as elsewhere in Germany".
After the invasion of Poland, the Luftwaffe engaged in massive air raids against most Polish cities, destroying various infrastructure such as hospitals and schools. Civilians and refugees were also attacked. Notably, Luftwaffe bombed Warsaw, Wieluń and Frampol.
The directives issued to the Luftwaffe for the Polish Campaign were to prevent the Polish Air Force from influencing the ground battles or attacking German territory. In addition, it was to support the advance of German ground forces through direct tactical and indirect air support with attacks against Polish mobilization centres and thus delay an orderly Polish strategic concentration of forces and to deny mobility for Polish reinforcements through the destruction of strategic Polish rail routes.
Preparations were made for a concentrated attack (Operation Wasserkante) by all bomber forces against targets in Warsaw. The bombing of the rail network, crossroads, and troop concentrations played havoc on Polish mobilisation, while attacks upon civilian and military targets in towns and cities disrupted command and control by wrecking the antiquated Polish signal network. Over a period of a few days, Luftwaffe numerical and technological superiority took its toll on the Polish Air Force. Polish Air Force bases across Poland were also subjected to Luftwaffe bombing from September 1, 1939.
On 13 September, following orders of the ObdL to launch an attack on Warsaw's Jewish Quarter, justified as being for unspecified crimes committed against German soldiers but probably in response to a recent defeat by Polish ground troops, and intended as a terror attack, 183 bomber sorties were flown with 50:50 load of high explosive and incendiary bombs, reportedly set the Jewish Quarter ablaze. On 22 September, Wolfram von Richthofen messaged, "Urgently request exploitation of last opportunity for large-scale experiment as devastation terror raid ... Every effort will be made to eradicate Warsaw completely". His request was rejected. However, Hitler issued an order to prevent civilians from leaving the city and to continue with the bombing, which he thought would encourage Polish surrender.
On 14 September the French Air attaché in Warsaw reported to Paris, "the German Air Force acted in accordance to the international laws of war [...] and bombed only targets of military nature. Therefore, there is no reason for French retorsions." That day - the Jewish New Year - the Germans concentrated again on the Warsaw's Jewish population, bombing the Jewish quarter and targeting synagogues. Three days later Warsaw was surrounded by the Wehrmacht, and hundreds of thousands of leaflets were dropped on the city, instructing the citizens to evacuate the city pending a possible bomber attack. On 25 September the Luftwaffe flew 1,150 sorties and dropped 560 tonnes of high explosive and 72 tonnes of incendiaries.
To conserve the strength of the bomber units for the upcoming western campaign, the modern He 111 bombers were replaced by Ju 52 transports using "worse than primitive methods" for the bombing. Due to prevailing strong winds they achieved poor accuracy, even causing some casualties to besieging German troops. As result of the aerial and artillery bombardment, intense street fighting between German infantry and armor units and Polish infantry and artillery, 10 percent of the buildings in the city were destroyed, and 40,000 civilians killed.
In 1939, following the German invasion of Poland and subsequent declaration of war by the United Kingdom and France, the war in the West began. Britain struck first, bombing warships and light vessels in several German harbors on 3 and 4 September. Eight German Kriegsmarine men were killed at Wilhelmshaven - the war's first casualties to British bombs; attacks on ships at Cuxhaven and Heligoland followed.
The British government banned attacks on land targets and German warships in port due to the risk of civilian casualties.For the Germans, Hitler's OKW Direktive Nr 2 and Luftwaffe Direktive Nr 2, both failed to mention strategic bomber raids and prohibited attacks upon enemy naval forces unless the enemy bombed Germany first, noting, "the guiding principle must be not to provoke the initiation of aerial warfare on the part of Germany." Still, Göring's directive permitted restricted attacks upon warships anywhere, as well as upon troop transports at sea. Nevertheless, Germany's first strikes were not carried out until the 16th and 17th of October, against the British naval bases at Rosyth and Scapa Flow. Little activity followed.Meanwhile, attacks by the Royal Air Force dwindled to less than one a month. As the winter set in, both sides engaged in propaganda warfare, dropping leaflets on the populations below. The Phony War continued.
On 16 March 1940, the Luftwaffe launched a strike against the British navy yard at Scapa Flow, leading to the first British civilian death. A British attack followed against the German airbase at Hörnum on the island of Sylt, hitting a hospital, although there were no casualties. The Germans retaliated with a naval raid.
On 10 May 1940, Germany invaded Belgium, the Netherlands and Luxembourg, intending to drive through the Ardennes into France and strike a quick blow that would end the war. This assault initiated the Battle of France. As it began, three German bombers from KG 51 mistakenly bombed the German city of Freiburg instead of the French airfield of Dole-Taveux, having lost their way over the Black Forest. The Germans reported it as an Allied 'terror attack', and not until 1956, when the mistake was brought to light by researchers, was the myth dispelled. Nevertheless, on 12 May 1940, the British did strike, and bombed the German industrial Ruhr Valley, including Cologne. While Allied light and medium bombers attempted to delay the German invasion by striking at troop columns and bridges, the British War Cabinet gave permission for limited bombing raids against targets such as roads and railways west of the River Rhine. The first British bombs fell on Mönchengladbach on the night of 11/12 May 1940, while Bomber Command was attempting to hit roads and railroads near the Dutch-German border; four people were killed. Targets in Gelsenkirchen were attacked first on the 14/15 May.
The Germans used the threat of bombing Rotterdam to try to get the Dutch to come to terms and surrender. After a second ultimatum had been issued by the Germans, it appeared their effort had failed and, on 14 May 1940, Luftwaffe bombers were ordered to bomb Rotterdam in an effort to force the capitulation of the besieged city. The controversial bombing targeted the center of the besieged city, instead of providing direct tactical support for the hard-pressed German 22nd Infantry Division (under Lt. Gen. von Sponeck, which had airlanded on May 10) in combat with Dutch forces northwest of the city, and in the eastern part of the city at the Meuse river bridge. At the last minute, Holland decided to submit and sent a plenipotentiary and other negotiators across to German lines. There was an attempt to call off the assault, but the bombing mission had already begun.
Out of 100 Heinkel He 111s, 57 dropped their ordinance, a combined 97 tons of bombs. In the resulting fire 1.1 square miles (2.8 km2) of the city center were devastated, including 21 churches and 4 hospitals. The strike killed between 800-1000 civilians, wounded over 1,000, and made 78,000 homeless. Nearly twenty-five thousand homes, 2,320 stores, 775 warehouses and 62 schools were destroyed.
International news agencies vastly exaggerated the events, portraying Rotterdam as a city mercilessly destroyed by terror bombing without regard for civilian life, with 30,000 dead lying under the ruins. Neither claim was true. Furthermore, the bombing was against well-defined targets, albeit in the middle of the city, and would have assisted the advancing German Army. The Germans had threatened to bomb Utrecht in the same fashion, and the Netherlands surrendered.
Following the attack on Rotterdam, RAF Bomber Command was authorized to attack German targets east of the Rhine on May 15, 1940; the Air Ministry authorized Air Marshal Charles Portal to attack targets in the Ruhr, including oil plants and other civilian industrial targets which aided the German war effort, such as blast furnaces (which at night were self-illuminating). On the night of 15/16 May, 96 bombers crossed the Rhine and attacked. 78 had been assigned oil targets, but only 24 claimed to have accomplished their objective. On the night of May 17/18, RAF Bomber Command bombed oil installations in Hamburg and Bremen; the H.E. and 400 incendiaries dropped caused six large, one moderately large and 29 small fires. As a result of the attack, 47 people were killed and 127 were wounded. Railway yards at Cologne were attacked on the same night. During May, Essen, Duisburg, Düsseldorf and Hanover were attacked in a similar fashion by Bomber Command. In June, attacks were made on Dortmund, Mannheim, Frankfurt and Bochum. At the time, Bomber Command lacked the necessary navigational and bombing technical background and the accuracy of the bombings during the night attacks was abysmal. Consequently, the bombs were usually scattered over a large area, causing an uproar in Germany. Furthermore, on the night of 7/8 June 1940 a single French Navy Farman F.223 bomber attacked Berlin. The attack occurred just days after Germany had bombed Paris.
On 22 June 1940, France signed an armistice with Germany. Britain was determined to keep fighting. On 1/2 July, the British attacked German warships Scharnhorst and Prinz Eugen  in the port of Kiel  and the next day, 16 RAF bombers attacked German train facilities in Hamm. Finally, on July 10, the Luftwaffe launched a strategic bombing campaign against the United Kingdom. Thus began the first phase of what came to be known as the Battle of Britain. The battle began with probing attacks on British coastal shipping, during which Hitler called for the British to accept peace, but the British refused to negotiate.
Hitler's No. 17 Directive, issued 1 August 1940, established the conduct of war against England and specifically forbade the Luftwaffe from conducting terror raids. The Führer declared that terror attacks could only be a means of reprisal, as ordered by him, despite the raids conducted by RAF Bomber Command against industries in urban Germany since May 1940. Hitler's instructions were echoed in Hermann Göring's general order, issued on 30 June 1940:
The war against England is to be restricted to destructive attacks against industry and air force targets which have weak defensive forces. ... The most thorough study of the target concerned, that is vital points of the target, is a pre-requisite for success. It is also stressed that every effort should be made to avoid unnecessary loss of life amongst the civilian population.—Hermann Göring 
On August 8, 1940, the Germans switched to raids on RAF fighter bases. To reduce losses, the Luftwaffe also began to use increasing numbers of bombers at night. By the last week of August, over half the missions were flown under the cover of dark. Despite Hitler's orders not to attack London, bombs fell on the city on 15 August, resulting in 60 deaths. That month, London was hit several more times, on the 18/19, 22/23, 24/25, 25/26 and 28/29. A raid on the 22/23 August, the first in which the Luftwaffe had hit central London, was described as 'extensive' by British observers.
On August 24, fate took a turn, and several off-course German bombers accidentally bombed residential areas of London. The next day, the RAF bombed Berlin for the first time, targeting Tempelhof airfield and the Siemens factories in Siemenstadt. These attacks were seen as indiscriminate bombings by the Germans due to their inaccuracy, and this infuriated Hitler; he ordered that the 'night piracy of the British' be countered by a concentrated night offensive against the island, and especially London. In a public speech in Berlin on 4 September 1940, Hitler announced that:
The other night the English had bombed Berlin. So be it. But this is a game at which two can play. When the British Air Force drops 2000 or 3000 or 4000 kg of bombs, then we will drop 150 000, 180 000, 230 000, 300 000, 400 000 kg on a single night. When they declare they will attack our cities in great measure, we will eradicate their cities. The hour will come when one of us will break - and it will not be National Socialist Germany!—Adolf Hitler 
The Luftwaffe, which Hitler had prohibited from bombing civilian areas in the UK, was now ordered to bomb British cities. The Blitz was underway. Göring - at Kesselring's urging and with Hitler's support- turned to a massive assault on the British capital. On 7 September, 318 bombers from the whole KG 53 supported by eight other Kampfgruppen, flew almost continuous sorties against London, the dock area which was already in flames from earlier daylight attacks. The attack of 7 September 1940 did not entirely step over the line into a clear terror bombing effort since its primary target was the London docks, but there was clearly an assumed hope of terrorizing the London population. Another 250 bomber sorties were flown in the night. By the morning of the 8 September, 430 Londoners had been killed. The Luftwaffe issued a press notice announcing they had dropped more than 1,000,000 kilograms of bombs on London in 24 hours. Many other British cities were hit in the nine month Blitz, including Birmingham, Liverpool, Southampton, Manchester, Bristol, Belfast, Cardiff, Clydebank, Kingston upon Hull and Coventry. Sir Basil Collier, author of 'The Defence of the United Kingdom', the HMSO's official history, wrote:
Although the plan adopted by the Luftwaffe early September had mentioned attacks on the population of large cities, detailed records of the raids made during the autumn and the winter of 1940-41 does not suggest that indiscriminate bombing of the civilians was intended. The points of aim selected were largely factories and docks. Other objectives specifically allotted to bomber-crews included the City of London and the governmental quarter rounds Whitehall.— Sir Basil Collier 
As the war continued, an escalating war of electronic technology developed. To counter German radio navigation aids, which helped their navigators find targets in the dark and through overcast, the British raced to work out the problems with countermeasures (most notably airborne radar, as well as highly effective deceptive beacons and jammers).
Despite causing a great deal of damage and disrupting the daily lives of the civilian population, the bombing of Britain failed to have an impact. British air defenses became more formidable, and attacks tapered off as Germany abandoned its efforts against Britain. Germany attacked the Soviet Union and the skies over London grew quiet.
The period of calm came to an end in April 1942 when, following a destructive RAF attack on the Hanseatic medieval city of Lübeck, Adolf Hitler ordered the Luftwaffe to retaliate, leading to the so-called Baedeker Blitz:
The Führer has ordered that the air war against England be given a more aggressive stamp. Accordingly, when targets are being selected, preference is to be given to those where attacks are likely to have the greatest possible effect on civillian life. Besides raids on ports and industry, terror attacks or retaliatory nature are to be carried out against towns other than London. Minelaying is to be scaled down in favour of these attacks.
In January 1944, a beleaguered Germany tried to strike a blow to British moral with terror bombing with Operation Steinbock. This late in the war, Germany was impeded by a shortage of planes and was unable to safely escort bombers across Western Europe towards Britain, as this was enemy-dominated airspace. However, German scientists had invented vengeance weapons - V-1 flying bombs and V-2 ballistic missiles - and these were used to launch an aerial assault on London and other cities in southern England from continental Europe. The campaign was much less destructive than the Blitz, so the British called it 'the Baby Blitz'. As the Allies advanced across France and towards Germany from the West, Paris, Liège, Lille and Antwerp also became targets.
The British and US directed part of the strategic bombing to the eradication of "wonder weapon" threats in what was later known as Operation Crossbow. The development of the V2 was hit preemptively in the British Peenemunde Raid (Operation Hydra) of August 1943.
British historian, Frederick Taylor asserts that "all sides bombed each other's cities during the war. Half a million Soviet citizens, for example, died from German bombing during the invasion and occupation of Russia. That's roughly equivalent to the number of German citizens who died from Allied raids."
On 14 February 1942, Directive No. 22 was issued to Bomber Command. Bombing was to be "focused on the morale of the enemy civil population and in particular of the industrial workers." Factories were no longer targets.
The effects of strategic bombing were very poorly understood at the time and grossly overrated. Particularly in the first two years of the campaign, few understood just how little damage was caused and how rapidly the Germans were able to replace lost production—despite the obvious lessons to be learned from the United Kingdom's own survival of the blitz.
Mid-way through the air war, it slowly began to be realized the campaign was having very little effect. Despite an ever-increasing tonnage of bombs dispatched, the inaccuracy of delivery was such any bomb falling within five miles of the target was deemed a "hit" for statistical purposes, and even by this standard, as the Butt Report made clear many bombs missed. Indeed sometimes in post raid assessment the Germans could not decide which town (not the installation in the town) had been the intended target because the scattering of bomb craters was so wide.
These problems were dealt with in two ways: first the precision targeting of vital facilities (ball-bearing production in particular) was abandoned in favour of "area bombing" – This change of policy was agreed by the Cabinet in 1941 and in early 1942 a new directive was issued and Air Marshal Arthur Harris (commonly known as "Bomber" Harris) was appointed to carry out the task – second as the campaign developed, improvements in the accuracy of the RAF raids were joined by better crew training, electronic aids, and new tactics such as the creation of a "pathfinder" force to mark targets for the main force, which was done over Harris' objections.
Harris, Air Officer Commanding Bomber Command, said "for want of a rapier, a bludgeon was used". He felt that as much as it would be far more desirable to deliver effective pin-point attacks, as the capacity to do so simply did not exist, and since it was war, it was necessary to attack with whatever was at hand. He accepted area bombing knowing it would kill civilians. However, Harris did authorize several precision bombing missions, such as attacks on Tirpitz, the Ruhr dams, and Dortmund–Ems Canal.
During the first few months of the area bombing campaign, an internal debate within the British government about the most effective use of the nation's limited resources in waging war on Germany continued. Should the Royal Air Force (RAF) be scaled back to allow more resources to go to the British Army and Royal Navy or should the strategic bombing option be followed and expanded? An influential paper was presented to support the bombing campaign by Professor Frederick Lindemann, 1st Viscount Cherwell, the British government's leading scientific adviser, justifying the use of area bombing to "dehouse" the German workforce as the most effective way of reducing their morale and affecting enemy war production.
Mr. Justice Singleton, a High Court Judge, was asked by Cabinet to look into the competing points of view. In his report, delivered on 20 May 1942, he concluded, "If Russia can hold Germany on land I doubt whether Germany will stand 12 or 18 months’ continuous, intensified and increased bombing, affecting, as it must, her war production, her power of resistance, her industries and her will to resist (by which I mean morale)". In the end, thanks in part to the dehousing paper, it was this view which prevailed and Bomber Command would remain an important component of the British war effort up to the end of World War II. A very large proportion of the industrial production of the United Kingdom was harnessed to the task of creating a vast fleet of heavy bombers—so much so other vital areas of war production were under-resourced. Until 1944, the effect on German production was remarkably small and raised doubts whether it was wise to divert so much effort – the response being there was nowhere else the effort could have been applied, as readily, to greater effect.
In mid 1942, the United States Army Air Forces arrived in the UK and carried out a few raids across the English Channel against Germany. In January 1943, at the Casablanca Conference, it was agreed RAF Bomber Command operations against Germany would be reinforced by the USAAF in a Combined Operations Offensive plan called Operation Pointblank. Chief of the British Air Staff MRAF Sir Charles Portal was put in charge of the "strategic direction" of both British and American bomber operations. The text of the Casablanca directive read: "Your primary object will be the progressive destruction and dislocation of the German military, industrial and economic system and the undermining of the morale of the German people to a point where their capacity for armed resistance is fatally weakened.", At the beginning of the combined strategic bombing offensive on 4 March 1943 669 RAF and 303 USAAF heavy bombers were available.
In Europe, the American Eighth Air Force conducted its raids in daylight and their heavy bombers carried smaller payloads than British aircraft in part because of their heavier (as needed) defensive armament. USAAF leaders firmly held to the claim of "precision" bombing of military targets for much of the war, and dismissed claims they were simply bombing cities. However the Eight received the first H2X radar sets in December 1943. Within two weeks of the arrival of these first six sets, the eighth command gave permission for them to area bomb a city using H2X and would continue to authorize, on average, about one such attack a week until the end of the war in Europe.
In reality, the day bombing was "precision bombing" only in the sense that most bombs fell somewhere near a specific designated target such as a railway yard. Conventionally, the air forces designated as "the target area" a circle having a radius of 1000 feet around the aiming point of attack. While accuracy improved during the war, Survey studies show that, in the over-all, only about 20% of the bombs aimed at precision targets fell within this target area. In the fall of 1944, only seven per cent of all bombs dropped by the Eighth Air Force hit within 1,000 feet of their aim point.
Nevertheless, the sheer tonnage of explosive delivered by day and by night was eventually sufficient to cause widespread damage, and, more importantly from a military point of view, forced Germany to divert resources to counter it. This was to be the real significance of the Allied strategic bombing campaign—resource allocation.
U.S. operations began with 'Pointblank' attacks, designed to eliminate key features of the German economy. These attacks manifested themselves in the infamous Schweinfurt raids. Formations of unescorted bombers were no match for German fighters, which inflicted a deadly toll. In despair, the Eighth halted air operations over Germany until a long-range fighter could be found; it proved to be the P-51 Mustang, which had the range to fly to Berlin and back.
With the arrival of the brand-new Fifteenth Air Force, based in Italy, command of the U.S. Air Forces in Europe was consolidated into the United States Strategic Air Forces (USSTAF). With the addition of the Mustang to its strength, the Combined Bomber Offensive was resumed. Planners targeted the Luftwaffe in an operation known as 'Big Week' (20–25 February 1944) and succeeded brilliantly - losses were so heavy German planners were forced into a hasty dispersal of industry and the day fighter arm never fully recovered.
On 27 March 1944, the Combined Chiefs of Staff issued orders granting control of all the Allied air forces in Europe, including strategic bombers, to General Dwight D. Eisenhower, the Supreme Allied Commander, who delegated command to his deputy in SHAEF Air Chief Marshal Arthur Tedder. There was resistance to this order from some senior figures, including Winston Churchill, Harris, and Carl Spaatz, but after some debate, control passed to SHAEF on 1 April 1944. When the Combined Bomber Offensive officially ended on 1 April, Allied airmen were well on the way to achieving air superiority over all of Europe. While they continued some strategic bombing, the USAAF along with the RAF turned their attention to the tactical air battle in support of the Normandy Invasion. It was not until the middle of September that the strategic bombing campaign of Germany again became the priority for the USSTAF.
The twin campaigns—the USAAF by day, the RAF by night—built up into massive bombing of German industrial areas, notably the Ruhr, followed by attacks directly on cities such as Hamburg, Kassel, Pforzheim, Mainz and the often-criticized bombing of Dresden.
Strategic bombing has been criticized on practical grounds because it does not always work predictably. The radical changes it forces on a targeted population can backfire, including the counterproductive result of freeing inessential labourers to fill worker shortages in war industries.
Much of the doubt about the effectiveness of the bomber war comes from the oft-stated fact that German industrial production increased throughout the war. While this is true, it fails to note production also increased in the United States, the United Kingdom, the Soviet Union, Canada and Australia. And, in all of those countries, the rate of production increased much more rapidly than in Germany. Until late in the war, industry had not been geared for war and German factory workers only worked a single shift (incredibly, German apprenticeships for aircraft electrical fitters still lasted four years at the war's end). Simply by going to three shifts, production could have been tripled with no change to the infrastructure. However, attacks on the infrastructure were taking place. The attacks on Germany's canals and railroads made transportation of materiel difficult.
The attack on oil production, oil refineries and tank farms was, however, extremely successful and made a very large contribution to the general collapse of Germany in 1945. In the event, the bombing of oil facilities became Albert Speer's main concern; however, this occurred sufficiently late in the war that Germany would soon be defeated in any case. Nevertheless, it is fair to say the oil bombing campaign materially shortened the war, thereby saving many lives.
German insiders credit the Allied bombing offensive with severely handicapping them. Speer repeatedly said (both during and after the war) it caused crucial production problems. Admiral Karl Dönitz, head of the U-Boat arm, noted in his memoirs that failure to get the revolutionary Type XXI U-boats (which could have completely altered the balance of power in the Battle of the Atlantic) into service was entirely the result of the bombing. The United States Strategic Bombing Survey (Europe), however, concluded the delays in deploying the new submarines cannot be attributed to air attack.
Although designed to "break the enemy's will", the opposite often happened. The British did not crumble under the German Blitz and other air raids early in the war. British workers continued to work throughout the war and food and other basic supplies were available throughout.
In Germany, the outcome was little different, even in the face of a bombing campaign which was far more extensive and comprehensive in effect, scope, and duration than that endured by Britain.
Within Asia the majority of strategic bombing was carried out by the Japanese and the US. The British Commonwealth planned that once the war in Europe was complete, a strategic bombing force of up to 1,000 heavy bombers ("Tiger Force") would be sent to the Far East. This was never realised before the end of the Pacific War.
Japanese strategic bombing was independently conducted by the Imperial Japanese Navy Air Service and the Imperial Japanese Army Air Service. Bombing efforts mostly targeted large Chinese cities such as Shanghai, Wuhan and Chonging, with around 5,000 raids from February 1938 to August 1943 in the later case.
The bombing of Nanjing and Canton, which began on 22 and 23 September 1937, called forth widespread protests culminating in a resolution by the Far Eastern Advisory Committee of the League of Nations. Lord Cranborne, the British Under-Secretary of State For Foreign Affairs, expressed his indignation in his own declaration.
Words cannot express the feelings of profound horror with which the news of these raids had been received by the whole civilized world. They are often directed against places far from the actual area of hostilities. The military objective, where it exists, seems to take a completely second place. The main object seems to be to inspire terror by the indiscriminate slaughter of civilians...—Lord Cranborne 
There were also air raids on Philippines and northern Australia (Bombing of Darwin, 19 February 1942). The Imperial Japanese Navy Air Service used tactical bombing against enemy airfields and military positions, as at Pearl Harbor. The Imperial Japanese Army Air Service also attacked enemy ships and military installations.
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The United States strategic bombing of Japan took place between 1942 and 1945. In the last seven months of the campaign, a change to firebombing tactics resulted in great destruction of 67 Japanese cities, as many as 500,000 Japanese deaths and some 5 million more made homeless. Emperor Hirohito's viewing of the destroyed areas of Tokyo in March 1945, is said to have been the beginning of his personal involvement in the peace process, culminating in Japan's surrender five months later.
The first U.S. raid on the Japanese main island was the Doolittle Raid of 18 April 1942 when sixteen B-25 Mitchells were launched from the USS Hornet (CV-8) to attack targets including Yokohama and Tokyo and then fly on to airfields in China. The raids were military pin-pricks, but a significant propaganda victory. Launched prematurely, none of the attacking aircraft reached the designated post mission airfields, either crashing or ditching (except for one aircraft, which landed in the Soviet Union, where the crew was interned). Two crews were captured by the Japanese.
The key development for the bombing of Japan was the B-29 Superfortress, which had an operational range of 1,500 miles (2,400 km); almost 90% of the bombs dropped on the home islands of Japan were delivered by this type of bomber (147,000 tons). The first raid by B-29s on Japan from China was on 15 June 1944. The planes took off from Chengdu, over 1,500 miles away. This first raid was also not particularly damaging to Japan. Only forty-seven of the sixty-eight B–29s that took off hit the target area; four aborted with mechanical problems, four crashed, six jettisoned their bombs because of mechanical difficulties, and others bombed secondary targets or targets of opportunity. Only one B–29 was lost to enemy aircraft. The first raid from the east was on 24 November 1944 when 88 aircraft bombed Tokyo. The bombs were dropped from around 30,000 feet (10,000 m) and it is estimated that only around 10% of the bombs hit designated targets.
The initial raids were carried out by the Twentieth Air Force operating out of mainland China in Operation Matterhorn under XX Bomber Command. Initially the Twentieth Air Force was under the command of Hap Arnold, and later Curtis LeMay. This was never a satisfactory arrangement because not only were the Chinese airbases difficult to supply via - materiel being sent over "the Hump" from India, but the B-29s operating from them could only reach Japan if they traded some of their bomb load for extra fuel in tanks in the bomb-bays. When Admiral Chester Nimitz's island-hopping campaign captured islands close enough to Japan to be within the range of B-29s, the Twentieth Air Force was assigned to XXI Bomber Command which organized a much more effective bombing campaign of the Japanese home islands. Based in the Marianas (Guam and Tinian in particular) the B-29s were now able to carry their full bomb loads and were supplied by cargo ships and tankers.
Unlike all other forces in theater, the Bomber Commands did not report to the commanders of the theaters but directly to the Joint Chiefs of Staff. In March 1945, they were placed under the U.S. Strategic Air Forces in the Pacific which was commanded by General Carl Spaatz.
As in Europe, the United States Army Air Forces (USAAF) tried daylight precision bombing. However, it proved to be impossible due to the weather around Japan, as bombs dropped from a great height were tossed about by high winds. General LeMay, commander of XXI Bomber Command, instead switched to mass firebombing night attacks from altitudes of around 7,000 feet (2,100 m) on the major conurbations of Tokyo, Nagoya, Osaka, and Kobe. Despite limited early success, particularly against Nagoya, LeMay was determined to use such bombing tactics against the vulnerable Japanese cities. Attacks on strategic targets also continued in lower-level daylight raids.
The first successful firebombing raid was on Kobe on 3 February 1945, and following its relative success the USAAF continued the tactic. Nearly half of the principal factories of the city were damaged, and production was reduced by more than half at one of the port's two shipyards.
Much of the armor and defensive weaponry of the bombers was removed to allow increased bomb loads; Japanese air defense in terms of night-fighters and anti-aircraft guns was so feeble it was hardly a risk. The first raid of this type on Tokyo was on the night of 23–24 February when 174 B-29s destroyed around one square mile (3 km²) of the city. Following on that success 334 B-29s raided on the night of 9–10 March, dropping around 1,700 tons of bombs. Around 16 square miles (41 km²) of the city was destroyed and over 100,000 people are estimated to have died in the fire storm. The destruction and damage was at its worst in the city sections east of the Imperial Palace. It was the most destructive conventional raid in all of history. The city was made primarily of wood and paper, and Japanese firefighting methods were not up to the challenge. The fires burned out of control, boiling canal water and causing entire blocks of buildings to spontaneously combust from the heat. The effects of the Tokyo firebombing proved the fears expressed by Admiral Yamamoto in 1939: "Japanese cities, being made of wood and paper, would burn very easily. The Army talks big, but if war came and there were large-scale air raids, there's no telling what would happen."
In the following two weeks, there were almost 1,600 further sorties against the four cities, destroying 31 square miles (80 km²) in total at a cost of 22 aircraft. By June, over forty percent of the urban area of Japan's largest six cities (Tokyo, Nagoya, Kobe, Osaka, Yokohama, and Kawasaki) was devastated. LeMay's fleet of nearly 600 bombers destroyed tens of smaller cities and manufacturing centers in the following weeks and months.
Leaflets were dropped over cities before they were bombed, warning the people and urging them to escape the city. Though many, even within the Air Force, viewed this as a form of psychological warfare, a significant element in the decision to produce and drop them was the desire to assuage American anxieties about the extent of the destruction created by this new war tactic. Warning leaflets were also dropped on cities that were not to be bombed to create uncertainty and absenteeism.
A year after the war, the United States Army Air Forces's Strategic Bombing Survey (Pacific War) reported that they had underestimated the power of strategic bombing combined with naval blockade and previous military defeats to bring Japan to unconditional surrender without invasion. By July 1945, only a fraction of the planned strategic bombing force had been deployed yet there were few targets left worth the effort. In hindsight, it would have been more effective to use land-based and carrier-based air power to strike against merchant shipping and begin aerial mining at a much earlier date so as to link up with the effective Allied submarine anti-shipping campaign and completely isolate the island nation. This would have accelerated the strangulation of Japan and ended the war sooner. A postwar Naval Ordnance Laboratory survey agreed, finding that naval mines dropped by B-29s had accounted for 60% of all Japanese shipping losses in the last six months of the war. In October 1945, Prince Fumimaro Konoe said that the sinking of Japanese vessels by U.S. aircraft combined with the B-29 aerial mining campaign were just as effective as B-29 attacks on industry alone, though he admitted that "the thing that brought about the determination to make peace was the prolonged bombing by the B-29s." Prime Minister Baron Kantarō Suzuki reported to U.S. military authorities that it "seemed to me unavoidable that in the long run Japan would be almost destroyed by air attack so that merely on the basis of the B-29s alone I was convinced that Japan should sue for peace."
On 6 August 1945, the "Little Boy" enriched uranium nuclear bomb was dropped on the city of Hiroshima, followed on 9 August by the detonation of the "Fat Man" plutonium core nuclear bomb over Nagasaki. To date these are the only uses of nuclear weapons in warfare.
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As many as 140,000 people in Hiroshima and 80,000 in Nagasaki have died from the bombings by the end of 1945, roughly half of the residential populations on the days of the bombings. Thousands more have been subsequently killed from injuries or the combined effects of flash burns, trauma, and radiation burns, compounded by illness, malnutrition and radiation sickness. Since then more have died from leukemia and solid cancers attributed to exposure to radiation released by the bombs. In both cities, the overwhelming majority of the dead were civilians.
On 15 August 1945, Japan announced its surrender to the Allied Powers, signing the Instrument of Surrender on 2 September which officially ended World War II. Furthermore, the experience of bombing led post-war Japan to adopt Three Non-Nuclear Principles, which forbade Japan from nuclear armament.