Military history


Super-weapons and the Defeat of Japan

Okinawa left an awful warning of what awaited the American forces as the Pacific war drew in towards the perimeter of the Japanese home islands. It was the first battle for a large island on the approaches to the empire’s heartland, and its cost and duration hinted at far worse ordeals to come once the United States Navy advanced to land soldiers and Marines on the shores of the Inland Sea. From a source never satisfactorily identified, the figure of ‘a million casualties’, even ‘a million dead’, had begun to circulate among American strategic planners as the number of losses to be expected in an invasion of Japan. It cast a terrible shadow over their discussions of how the victorious campaign in the Pacific was to be brought to an end without a national tragedy.

So far – and this implies no slur on the courage, dedication and self-sacrifice of the American sailors, Marines and soldiers who fought and died in the front line – the Pacific war had been a small war. The number of major ships engaged exceeded that deployed in any other theatre: with a dozen battleships, fifty aircraft carriers, fifty cruisers, 300 destroyers and 200 submarines, the Pacific Fleet in 1945 was not only the largest navy in the world but the largest navy that had ever existed; it had extinguished the Imperial Japanese Navy, whose few units still afloat lacked the fuel for them to put to sea. The American naval air force, 3000 strong, was also the largest in being; in addition the navy and the US Army Air Force had tens of thousands of shore-based aircraft, including the B29 Superfortress, 250 of which had begun to operate regularly against Japanese cities since March, with devastating effect.

The Pacific war had been an enormous war in its geographical scope, encompassing over 6 million square miles of land and ocean. In terms of human numbers, however, the war had been quite small compared to that fought in Europe. There the Soviet Union had mobilised 12 million men against Germany’s 10 million, and the theatre had also engaged most of Britain’s 5 million and about a quarter of the United States’ 12 million. In the Pacific, by contrast, although the Japanese had mobilised 6 million men, five-sixths of those deployed outside the home islands had been stationed in China; the number committed to the fighting in the islands had perhaps not exceeded that which America had sent. Between 1941 and 1945 a million and a quarter United States servicemen were posted to the Pacific and China-Burma-India theatres; of these, however, only 450,000 belonged to army or Marine divisions, and of those twenty-nine divisions only some six army and four Marine divisions were involved in regular periods of prolonged combat. Compared to the European theatre, where in mid-1944 300 German and satellite divisions confronted 300 Russian and seventy British and American divisions, the ‘ground combat’ dimension of the Pacific war was small indeed – if one sets aside the appalling casualties suffered by the Japanese island garrisons.

In the aftermath of Okinawa, its scale suddenly threatened to swell exponentially. The surrender of Germany meant that all of the ninety divisions the United States had mobilised and most of the British Empire’s sixty could be made available for the invasion of Japan, together with whatever proportion of the Red Army Stalin decided to allot as soon as he declared war (as he had undertaken to do, once Germany was defeated, at Tehran in November 1943). According to the Okinawan experience, however, even numbers such as these could not guarantee that the defeat of the Japanese on their home territory would be quick or cheap. Okinawa and Japan were similar in terrain, but Japan offered a defender a vast succession of ridge, mountain and forest positions from which to hold an invader at bay. The prospect appalled the United States’ decision-makers. Admiral William Leahy, chairman of the Joint Chiefs of Staff, pointed out to President Truman at a meeting on 18 June that the army and Marine divisions had suffered 35 per cent casualties on Okinawa, that a similar percentage could be expected in an attack on Kyushu, the first of the Japanese home islands selected for invasion, and that, with 767,000 men committed to the operation, the toll of dead and wounded would therefore amount to 268,000, or about as many battle deaths as the United States had suffered throughout the world on all fronts so far.

Truman’s comment was that he ‘hoped there was a possibility of preventing an Okinawa from one end of Japan to the other’. The Joint Chiefs’ plan, worked out in Washington at the end of May 1945, called for an invasion of Kyushu (codenamed Olympic) in the autumn of 1945 and an assault on the main island of Honshu (codenamed Coronet) in March 1946. It had been agreed with difficulty. The army, whose view had been largely fixed by MacArthur, insisted that only an invasion would definitively finish the war. The navy, to which the US Army Air Force commanders lent unspoken support, argued that the seizure of bases on the coast of China from which close-range strategic air bombardment could be mounted would reduce Japanese resistance without the need to risk American lives in an amphibious landing. Strategic bombing, however, had thus far inflicted little damage on the home islands and had had insignificant effect upon its government’s will to war. MacArthur’s view therefore prevailed.

The destruction of Japan’s cities

Before the Joint Chiefs of Staff issued their directive for Olympic and Coronet, however, the strategic bombing campaign had taken a different turn. Like the British bomber chiefs in 1942, the Americans had been constrained to abandon the belief – which they had held much more dogmatically than the British – that the bomber was a precision tool and to accept that it had to be used as a blunt instrument. They had been driven to that change of doctrine by the success of the Japanese (in imitation of Speer’s programme in Germany in 1943-4) in dispersing production of weapon components away from the main industrial centres to new factories which could not be easily located or hit by the Twentieth Air Force. In February 1945 General Curtis LeMay arrived in the Marianas, which had become the main base for the Superfortresses of XXI Bomber Command, to implement new bombing tactics. Targets were to be subjected not to precision high-level daylight strikes by high explosive but to low-level drenching by incendiary bombs at night, exactly the method by which ‘Bomber’ Harris had made his ‘thousand-bomber raids’ an instrument of terror in 1942 and created firestorms in one German city after another. The incendiary bomb LeMay’s aircrew used, however, being filled with jellified petrol, was a far more efficient agent of conflagration than the RAF’s; more important, Japan’s flimsy wood-and-paper cities burned far more easily than European stone and brick.

On 9 March Bomber Command attacked Tokyo with 325 aircraft armed exclusively with incendiaries, flying at low altitude under cover of darkness. In a few minutes of bombing the city centre took fire and by morning 16 square miles had been consumed; 267,000 buildings burned to the ground, and the temperature in the heart of the firestorm caused the water to boil in the city’s canals. The casualty list recorded 89,000 dead, half as large again as the number of injured survivors treated in the city’s hospitals. Losses to the bombers were below 2 per cent and were to decline as the campaign gathered force. LeMay’s command soon rose in strength to 600 aircraft and brought one city after another under attack; by mid-June Japan’s five other largest industrial centres had been devastated – Nagoya, Kobe, Osaka, Yokohama and Kawasaki – 260,000 people had been killed, 2 million buildings destroyed and between 9 and 13 million people made homeless.

The destruction continued relentlessly, at virtually no loss to the American bomber crews but at appalling cost to Japan; by July 60 per cent of the ground area of the country’s sixty larger cities and towns had been burnt out. As MacArthur and other military hardheads had argued, however, the devastation did not seem to deflect the Japanese government from its commitment to continuing the war. In early April, after failing to draw China into a separate peace, Koiso had been replaced as Prime Minister by a moderate figurehead, the seventy-eight-year-old Admiral Kantaro Suzuki; Tojo, though a deposed Prime Minister, nevertheless retained a veto over cabinet decisions through his standing in the army, and he and other militarists were determined to fight it out to the end. This determination exacted sacrifices which even Hitler had not demanded of the Germans in the closing months of the war. The food ration was reduced below the 1500 calories necessary to support life, and more than a million people were set to grubbing up pine roots from which a form of aviation fuel could be distilled. On the economic front, reported a cabinet committee instructed by Suzuki to examine the situation, the steel and chemical industries were on the point of collapse, only a million tons of shipping remained afloat, insufficient to sustain movement between the home islands, and the railway system would shortly cease to function. Still no one dared speak of peace. Tentative openings made in May through the Japanese legation in Switzerland by the American representative, Alan Dulles, were met with silence; over 400 people were arrested in Japan during 1945 on the mere suspicion of favouring negotiation.

The search for revolutionary weapons

In midsummer the American government began both to lose patience at Japan’s intransigence and to yield to the temptation to end the war in a unique, spectacular and incontestably decisive way. They were aware through Magic intercepts that the Suzuki cabinet, like Koiso’s before it, was pursuing backdoor negotiations with the Russians, whom it hoped would act as mediators; they were also aware that a principal sticking-point in Japan’s attitude to ending the war was the ‘unconditional surrender’ pronouncement of 1943, which all loyal Japanese recognised as a threat to the imperial system. However, since the Russians mediated in no way at all, and since the Potsdam conference following the surrender of Germany indicated that unconditional surrender need not extend to the emperor’s deposition, America’s willingness to wait attenuated during the summer. On 26 July the Potsdam Proclamation was broadcast to Japan, threatening ‘the utter destruction of the Japanese homeland’ unless the imperial government offered its unconditional surrender. Since 16 July President Truman had known that ‘utter destruction’ lay within the United States’ power, for on that day the first atomic weapon had been successfully detonated at Alamagordo in the New Mexico desert. On 21 July, while the Potsdam meeting was in progress, he and Churchill agreed in principle that it should be used. On 25 July he informed Stalin that America had ‘a new weapon of unusually destructive force’. Next day the order was issued to General Carl Spaatz, the commander of the Strategic Air Forces, to ‘deliver its first special bomb as soon as weather will permit visual bombing after about 3 August 1945 on one of the targets: Hiroshima, Kokura, Niigata and Nagasaki’. The attempt to bring the Second World War to an end by the use of a revolutionary super-weapon had been decided.

The search for a revolutionary weapon was one of the most immediate and persistent outcomes of the industrialisation of war in the mid-nineteenth century, and both a logical and an inevitable extension of the revolution in war which preceded it. Until the fifteenth century, warfare was a muscular activity, and decision on the battlefield went to the side which could sustain muscular effort longer than the other. The invention of gunpowder changed that; by allowing energy to be stored in chemical form, it made the weak man the equal of the strong and transferred advantage in war to the side which possessed superior intellectual quality and morale. The first attempts to draw on the products of industrialisation for military purpose therefore took the form of multiplying the power of chemical energy by accelerating the rate at which projectiles could be discharged; breech-loading and magazine rifles and then the machine-gun were the result. Their purpose was to nullify morale and intellectual quality by weight of metal.

When human resilience and adaptability demonstrated that the fighting man of the industrial age could survive even quantum leaps in firepower, military inventors changed their tack. They began to apply their inventiveness not to the problem of killing or disabling warriors en masse but to attacking and destroying the protective systems in which they took shelter – on land, fortifications; at sea, armoured ships. Human ingenuity had sought a means of destroying ships by stealth even before the industrial age, and the idea of the submarine and the torpedo had found primitive forms in sailing days. Between 1877 and 1897 both the torpedo and the submarine emerged as practicable weapons and did indeed transform the nature of naval warfare. The tank, which appeared in 1916, promised a comparable transformation of land warfare.

The promise, however, proved illusory. Tank and submarine, though they appeared to be strategic weapons in essence, were more or less quickly revealed to be tactical; that is to say, they were susceptible to counter-measures at the point of encounter and they struck at the products, not the structure, of an enemy’s war-making system. However great the human losses and material damage they inflicted at the battlefront, the enemy, as long as he could replace those losses and repair that damage from his internal resources, might continue to wage war. The production of tanks and submarines, as those committed to battle were destroyed and had to be replaced from current output, itself became a charge on industrial capacity and therefore merely raised instead of reducing the price of victory.

This perception was one of the most important military legacies of the First World War. It was to lead to the formulation of the theory of strategic bombing. In the years after the war, both the British and the American air forces were converted to the belief that the heavy bomber, by carrying the high explosive which had proved so ineffectual against trench systems to the industrial heartland of the enemy, could quickly and finally destroy his means of making war and so win victory without the need for armies or navies to fight ‘decisive’ battles at all. The British further persuaded themselves that if such a ‘strategic bombing’ campaign were carried out at night it would spare the bombing force appreciable loss, while the Americans independently arrived at the conclusion advanced by the Italian dogmatist, Giulio Douhet, that a large, heavily armed day-bomber could be made self-defending: the Flying Fortress was the result.

As we have seen, the experience of war proved the theory of strategic bombing to be ill founded. A major cause of its failure lay in the realisation of one of the war’s greatest scientific endeavours, the development of radar. Invented by the British before the outbreak, in 1940 it provided an effective though static chain of early-warning stations which allowed Fighter Command to be directed quickly and accurately against incoming Luftwaffe raids during the Battle of Britain. The British invention of the cavitron valve, which became operational in 1942, enabled radar to function at ‘centimetric’ wavelengths on a directional arc. These developments, which greatly reduced the bulk of radar sets, increased the definition of the image received and allowed the operator to search a chosen sector of air space, meant that effective search radars could be mounted in night-fighters; a further application of the cavitron valve was the miniaturised radar proximity fuse, introduced in August 1944, which exploded an anti-aircraft shell at a range lethal to an aircraft. It was used with considerable success against the V-1s. When ‘centimetric’ radar was developed by the Germans, however, they began to inflict a heavy toll on Bomber Command during its night raids on the Reich; had they also discovered the secret of miniaturising radar fusing for anti-aircraft shells, the American formations bombing by daylight would have suffered proportionately.

By 1944 it had become clear to all but the dogmatists in Bomber Command and the US Eighth Air Force that strategic bombing would not win the war in Europe (just as in mid-1945 it seemed clear that the fire-bombing of the home islands would not beat Japan). The strategic bomber, like the submarine and the tank, had been revealed to be a weapon susceptible to counter-measures, a system that required expensive ‘dedicated’ defences to protect it and a victim of attritional losses which imposed a heavy and continuing charge on war production. If there was such a thing as a revolutionary war-winning weapon, the search for it lay in another direction.

Hitler’s ‘revenge weapons’

In one field of the search, the Germans had made greater progress than any of the other combatants. They were on the point of deploying a ballistic missile. German pilotless weapon research had an extended history, much of it intertwined with the life stories of two individuals, Werner von Braun and Walter Dornberger. Von Braun was a professional technologist whose youthful enthusiasm for the idea of space travel had translated itself by the late 1920s into practical experimentation with rockets. Dornberger was a regular gunner officer who had served with the heavy artillery in the First World War and in 1930 was charged with rocket development at the Army Weapons Office. Circumstances brought the two into contact and in 1932 they began to experiment together with rocket firings. Braun supplied the technical expertise, Dornberger defined the practical criteria a successful rocket would have to meet. ‘I had been a heavy gunner,’ he wrote. ‘Gunnery’s highest achievement to date had been the huge Paris Gun’, which fired ‘a 21-cm shell with about 25 lb of high explosive about 80 miles. My idea of a first big rocket was something that would send a ton of high explosive over 160 miles.’ He also ‘stipulated a number of military requirements, among others that for every 1000 feet of range a deviation of only 2 or 3 feet [from the chosen impact point] was acceptable.’ He finally ‘limited the size of the rocket by insisting that we must be able to transport it intact by road and that it must not exceed the maximum width laid down for road vehicles.’

Dornberger’s prescription revealed both the institutional roots of his thinking and, at the same time, an astonishing prescience of the rocket’s potential. His insistence on road transportability went back to the characteristics of the 305-mm and 420-mm guns with which the German artillery had devastated the Belgian forts in 1914; it ensured that future German ballistic missiles would be weapons of the artillery arm. His requirements for range, accuracy and size of warhead, on the other hand, cast German rocket research far into the future. What he demanded, in effect, was a prototype for the transportable ballistic missile which has become the principal strategic weapon of the superpowers in the late twentieth century. When, later, he was to insist that the successful production model (known to the Germans as the A-4, to the Allies as the V-2) should move on a vehicle (the Meillerwagen) which was also its launcher, he ensured the appearance of the ‘transporter-erector’ which in our own time has made the Soviet SS-20 and the American Pershing 2 instruments of strategic power so ‘survivable’ that their existence has produced the world’s first ever categorical agreement of disarmament between leading military powers.

The German army’s decision to invest in rocket development was motivated by the provisions of the Versailles treaty, which forbade it to possess heavy artillery but did not proscribe rockets. By 1937, however, when work on the V-2’s predecessors was sufficiently advanced for Braun and Dornberger to have secured funds to establish a testing station on the Baltic island of Peenemünde, Hitler had already breached the Versailles treaty at every point. The rocket team’s current preoccupation was to sustain funding to continue research. The army favoured the programme, since the V-2 was to be an army weapon, and provided finance. In October 1942 a successful test firing was staged, in December Speer, the Armaments Minister, authorised mass production, and on 7 July 1943 Hitler, after viewing a film of a missile launch, designated it ‘the decisive weapon of the war’ and announced that ‘whatever labour and materials [Braun and Dornberger] need must be supplied instantly.’

By 1943, however, the British were already aware that the German ballistic missile programme was well advanced. Warning from a still-unidentified German wellwisher, received in Norway in 1940 and known as the ‘Oslo Report’, had alerted London to the existence of a missile research programme. The trail had then gone cold, but had revived when new evidence suggested in December 1942 that a ballistic missile was under development in Germany and, in April 1943, that the Luftwaffe was also experimenting with a pilotless aircraft. Both clues came from ‘Humint’ (human intelligence, or the word of agents’ contacts), one of its few successes of the war. By June both German programmes had been identified as centring on Peenemünde, where in fact the Luftwaffe was developing the FZG-76 (V-1 flying-bomb) at one end of the island while Dornberger and Braun worked on the V-2 rocket at the other. On 29 June Churchill personally ordered Bomber Command to take Peenemünde under heavy attack and on the night of 16/17 August it was attacked by 330 aircraft and devastated.

The Peenemünde raid so gravely set back the German pilotless weapons programme that it was not until 12 June 1944 that the first flying-bomb landed in Britain; 8 September was the date of the first successful V-2 rocket attack. By then the Luftwaffe’s 155 Regiment had been driven back from the positions whence its V-1s could reach England; as a result, out of the 35,000 produced, only 9000 were fired against England and of these over 4000 were destroyed by anti-aircraft fire or fighter attack. The V-2s were never fired from their chosen launch sites in northern France; from Holland they could just reach London, on which 1300 impacted, and after October an equal number were directed at Antwerp, which by then was the Allied Liberation Armies’ main logistic base.

The V-2s killed 2500 Londoners between 8 September 1944 and 29 March 1945, when their launch positions were finally overrun by the 21st Army Group. Britain had had a lucky escape – and perhaps also America, for Braun and Dornberger had already written the specifications for a missile, designated the A10 and utilising the V-2 (A-4) as its second stage, which would have had a range of 2800 miles and been launched across the Atlantic. Under other circumstances, moreover, these missiles, to which the Allies had not even the beginnings of a counterpart and no counter-measure whatsoever, would have carried a warhead as revolutionary in nature as the missiles were themselves. For Germany too had its atomic weapons programme.

It was the crowning mercy of the Second World War that it came to nothing. For a complex of reasons, which included Nazi Germany’s self-deprivation of significant scientific talent by its persecution of the Jews, but also the inefficient multiplication of research programmes by as many as a dozen agencies which all hoped to win the Führer’s favour by bringing him news of the successful development of the super-weapon, the American atomic intelligence team which ransacked Germany in May 1945 found that ‘they were about as far as we were in 1940, before we had begun any large-scale work on the bomb at all’. In the last months of his life, Hitler, whose enthusiasm for nuclear weapons, as for ballistic missiles, developed too late in the war to ensure their decisive operational deployment, attempted to revitalise those about him with promises of unanswerable vengeance on his enemies. However, the evidence showed that, ‘although [he] had been advised of the possibility of an atomic weapon in 1942, the Germans had failed to separate U 235 [the essential fissile element] and that, while they had apparently started separation on a small scale by means of a centrifuge and were constructing a uranium pile, they had only recently succeeded in manufacturing uranium metal . . . and had not by August 1944 taken their experiments to the point at which they were aware of the difficulties they would have to overcome before the pile would function.’

In short, the Germans were years from manufacturing an atomic bomb at the time when the Allied atomic weapons programme was already close to fulfilment. In October 1939 Albert Einstein, then the most famous man of science in the world and an émigré to the United States, had nevertheless been prompted by two younger physicists to write to President Roosevelt warning that Germany might be bent on an atomic weapons programme and suggesting that the United States should study the possibility itself; Roosevelt set up a ‘Uranium Committee’, which reported in July 1941 that the project was feasible and, if so, would be ‘determining’. In 1942 the British, who had been pursuing their own researches with excellent manpower but insufficient funds, amalgamated their efforts with those of the Americans in the United States. By 1945 120,000 people were employed by the Manhattan Project, which had succeeded in separating uranium 235 and the synthetic element plutonium and in developing mechanisms to explode both as warheads of bomber-borne weapons.

It was the uranium 235 version of this atomic bomb that the B-29 Enola Gay dropped over Hiroshima on the morning of 6 August 1945; a few hours later, while 78,000 people lay dead or dying in the ruins, a White House statement called on the Japanese to surrender or ‘they may expect a rain of ruin from the air’. No word being received, on 9 August another B-29 flew from Tinian to bomb the city of Nagasaki, killing 25,000. The United States thus temporarily exhausted its supply of nuclear weapons and awaited the outcome of the damage done.

On 8 August, following a warning it had issued in April that it would repudiate its 1942 non-aggression treaty, the Soviet Union declared war on Japan and opened a vast offensive into Manchuria the following day. This offensive had been promised to the Western Allies, but the Americans had grown decreasingly enthusiastic for it as the moment to launch their atomic strike approached. Stalin had shown little surprise when told by Truman at Potsdam of America’s ‘secret weapon’; as we now know, the treachery of certain Western scientists, in particular the German communist émigré Klaus Fuchs, had revealed its existence to the Soviets already. Marshall, the American chief of staff, was particularly insistent that Russian intervention was no longer necessary to the success of the Allied cause and would win them advantages in the Far East which the United States would find cause to regret. He equally admitted that there was no means of deterring the Russians from their offensive, which had been in preparation ever since the German surrender. Three Far-Eastern Army Groups had been formed from the best-equipped and most experienced veterans of the European campaign, the third under the famous Marshal R. Y. Malinovsky. They were highly mechanised, the Japanese Kwantung Army was not. Though 750,000 strong, and regarded as the best formation in the imperial army, it had little recent experience of fighting. It bitterly defended the approaches to the central Manchurian plain, but when the Soviet Sixth Guards Tank Army broke out into open country on 13 August large sections of it were rapidly enveloped. The remainder was driven back across the river Yalu into northern Korea, where fighting continued until a final Japanese collapse on 20 August.

By then the Japanese forces everywhere else within the Pacific war zone had made their surrender to whichever Allied troops were at hand. On 15 August Emperor Hirohito, in the first public speech a Japanese sovereign had ever made, broadcast to his soldiers, sailors and people to announce that his government had decided to treat with the enemy. Explaining that the war had ‘turned out not necessarily to Japan’s advantage’ and that the enemy had begun ‘to employ a new and most cruel bomb’, he called upon them, in a series of strange and obscure phrases which never mentioned surrender, to accept the coming of peace. A few intransigents disobeyed and attempted briefly to continue the fight; a few irreconcilables committed ritual suicide. The rest of the emperor’s seventy million subjects relapsed instantly into the posture of defeat. On 28 August MacArthur arrived at Yokohama to institute the American occupation and reconstitution of Japan. On 2 September, aboard the battleship Missouri lying in Tokyo Bay, in the presence of representatives of Britain, the Soviet Union, China, France, Australia, New Zealand and Canada, MacArthur and the Japanese Foreign Minister, chief of staff and chief of naval operations signed the instrument of surrender. The Second World War was over.

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