Destroyer of Worlds: the bombing of Hiroshima and Nagasaki

14 mins read

‘I am become death, the destroyer of worlds.’ So spoke J Robert Oppenheimer, the nuclear physicist who developed the atom bomb. Marking one of history’s most terrible anniversaries, Stephen Roberts explores the arguments around the atomic destruction of two Japanese cities in August 1945.

Atomic desert: the view across
Hiroshima after the bombing
Atomic desert: the view across Hiroshima after the bombing’

On 6 August 1945 an atomic bomb, given the inappropriate name of ‘Little Boy’, was released by the Enola Gay, a B-29 Superfortress of the US Air Force, over the central Japanese city of Hiroshima, the country’s eighth largest. The time was 8.15am.

The detonation generated the power of 12,500 tons of conventional explosive, and created injuries of a kind never previously seen. Two-thirds of the city was destroyed, with as many as 140,000 civilians killed (estimates vary).

Few people in the immediate vicinity of the epicentre were thought to have survived, as four square miles of homes and factories were levelled. The effect was ‘obliterating’. As World War II drew to a close, the world entered a new, frightening era of warfare: that of WMDs, ‘Weapons of Mass Destruction’.


The ‘bomb’ had been coming for some years. In a pre-prepared statement issued on the day of Hiroshima, Churchill confirmed that the technology had been known about since 1939, it being ‘widely recognised among scientists of many nations that the release of energy by atomic fission was a possibility’.

The potential was great, and the Government felt it worth the investment of time and money to develop a weapon, even though the war imposed many other demands on scientists, and there was no guarantee that an atomic bomb could be designed, built, and used before the war ended.

In October 1941, Roosevelt suggested US and British efforts be pooled, which saw Brits deployed to the States to work on the top-secret project. By the summer of 1942, it was evident the work was getting somewhere and large-scale production plants were needed. These would be constructed in America; Britain not an option because of the bombing risk.

British scientists had made good progress on ‘the bomb’. In fact, they probably had greater knowledge than their American counterparts up to the point when the project moved across the water. Henceforward, though, it proceeded as an American project, and the British were sidelined.

The US came to regard the monster as its ‘baby’, with Oppenheimer appointed scientific director of the Manhattan Project in June 1942. Political responsibility fell to US Secretary of War, Henry Stimson, who had firmly stated US opposition to Japanese expansion in Asia as early as 1932 – the so-called ‘Stimson Doctrine’.


The Allies were conscious they could be in a race with the Germans to be the first to achieve the new technology – hence commando raids on Norway during 1942 and 1943, to take out ‘heavy water’ installations, an element in one of the possible processes involved in creating a bomb.

Come 1945, the man with his finger on the button was US President Harry Truman. Elected Vice-President only in 1944, and becoming President in April 1945 on Roosevelt’s death, Truman was immediately thrust into the maelstrom of tough decision-making, in spite of his short apprenticeship.

‘I am become death.’ J Robert Oppenheimer (1904-1967), nuclear physicist and head of the Manhattan Project.
‘I am become death.’ J Robert Oppenheimer (1904-1967), nuclear physicist and head of the Manhattan Project.

He has been portrayed as a man facing a conundrum of the first order. What was the best way to end WWII? To fight the Japanese to a finish, at an immense cost in American service lives (some estimates say as many as half a million), or to use the bomb?

How true is this picture of a President agonising over the ultimate life-and-death decision?

Mark Arnold-Forster believes Truman’s motives were sincere – a genuine desire to save American lives.

This is surely incomplete. To use the weapon was to demonstrate US power, not only to the defeated Japanese, but also to the world at large, and in particular to the new great rival, the Soviet Union. Nor was it enough to demonstrate its existence and potential. To ram the point home – and, in effect, to carry out a weapons test – it was necessary to attack a live target.


Max Hastings argues that once the US had the technology, it was bound to use it, seeing it as just another weapon in its arsenal. All the time and dollars spent on Manhattan were not going to be wasted in a last-minute attack of moral scruples.

Perhaps Hiroshima and Nagasaki should be viewed not as some isolated aberration, but as an extension of the series of pulverising air attacks on Japan – from B-29 to atom bomb at the stroke of a pen.

To be fair, many politicians and military leaders did not fully appreciate quite what they had created. Early on, Churchill seemed to think it was technology that just ‘promised more’ than existing capability. Later, Truman, Stimson, Marshall, and others grasped that the bomb – the Bomb – was devastating, but not what this meant for mankind.

Thinking seemed muddled in the US, as Marshall continued planning for ‘Olympic’ (target Kyushu) right up to August, seemingly not appreciating the atom bomb was the endgame.

Major-General Leslie Groves, in charge of Manhattan, was committed to using the weapon, and was unmoved by ethical arguments. It was the scientists who appeared troubled. Edward Teller summed up. ‘I have no hope of clearing my conscience. The things we are working on are so terrible that no amount of protesting or fiddling with politics will save our souls.’

A debate ensued about whether a technical demonstration of the bomb’s power might be sufficient to cow Japan into submission, rather than targeting a civilian population. This reached its apogee over the weekend of 14-16 July, when the outcome favoured the hawks.


Three days after Hiroshima, Japan was treated to a second atomic attack, as Nagasaki was targeted, by a bomb with the more appropriate moniker of ‘Fat Man’. An identical atomic bomb as before, again released by the US Air Force, destroyed 50% of the city. Ironically – and tragically for its people – Nagasaki had not been the second bomb’s original target. Kokura was reprieved as bad weather had prevented accurate location.

The Allies faced a confused situation in South-East Asia as the war headed towards its end. With the Japanese clearly losing, fighting was already breaking out between Chiang Kai-Shek’s Nationalists and Mao’s Communists in China.

‘I am become death.’ J Robert Oppenheimer
(1904-1967), nuclear physicist and head of the
Manhattan Project.
A timeline from the original print article in Military History Matters magazine.

Chiang had been Allied Supreme Commander in China throughout the war, and was regarded as the man who would head the fourth Great Power after the war – a notion nullified within four years by the Chinese Communist Revolution of 1949.

The Allies, as in Europe, were not only trying to finish the war: they also had one eye on the post-war world. This included growing interest in WMDs of all kinds – and in the scientists and units that had developed these during the war.

As Imperial Japan staggered, the atrocities committed by its forces became better known. Those against the civilian population in China, New Guinea, and the Philippines had been legion, including herding prisoners like cattle as a food source for hungry soldiers.

But there were other horrors emanating from the Japanese Empire that were no secret to the Allies. WMDs already existed in the form of chemical and biological weapons, the brainchild of Unit 731, the biological warfare establishment set up by the Japanese in 1938.

Experiments were carried out on PoWs, and attempts were made to release some ‘agents’ against the enemy. Controversially, the practitioners of Unit 731 were guaranteed immunity at the war’s close, as the Americans secured this ‘secret’ data for their own purposes.


Okinawa was a turning-point in US strategy. The infantry assault, which began on 1 April, was met with fierce resistance amid heavy rain. Casualties were high. Public opinion back home was outraged, not at the Japanese, but at US commanders: so many ‘boys’ lost taking a remote and fairly meaningless bit of field and mountain in a manner recalling WWI and Flanders.

War-weariness, it seemed, had gripped America. To add to the misery, kamikazes sank 27 ships and damaged 164 while the island was fought over. The Japanese had arguably achieved their objective: persuading the Americans that an invasion of the mainland would be too costly. Negotiated peace?

After Okinawa fell on 22 June, the US considered its next move. The invasion of the ‘home islands’ was fraught with difficulty. The determination of their Japanese opponents to refuse surrender, kamikaze attacks, and now the horrors that might be unleashed by Unit 731 focused minds.

‘Island-hopping’ brought the US closer to Japan. By August, two more islands in the Marianas, Guam and Tinian, were in US hands. Tinian would be the base from which the Enola Gay would fly.


As early as 1944, plans had existed for the invasion of Japan. MacArthur, to the dismay of many senior Americans, was to be supreme commander for ‘Operation Olympic’.

Agreed by the Chiefs of Staff, it envisaged casualties of 100,000 just to secure the southern island of Kyushu. Operation Coronet, projected for March 1946, would likely cost another 250,000 in taking the main island of Honshu.

Another option was to bomb and starve Japan into surrender, a strategy favoured by Admiral King and General Arnold. Daylight bombing started in June 1944, courtesy of Major-General Curtis Le May’s 21st Air Force. Then, from March 1945, night raids began: that of 9/10 March on Tokyo killed 83,000 people and destroyed about one quarter of the city and 10,000 acres, as 325 aircraft attacked at low-level. One million were rendered homeless that night. But the war went on.

 A table from the original print article in Military History Matters magazine.
A table from the original print article in Military History Matters magazine.

Tuesday 8 May was VE Day. The war in Europe was over. For those fighting against Japan, however, there seemed no end in sight.

By late June 1945, most of Japan’s war industry lay in ruins, and come 10 July the US Third Fleet under Halsey closed in and began its own carrier air-strikes.

Such was the devastation that US planes were now struggling to find worthwhile targets. There was no let-up, though. A hundred new B-29s were rolling out of America’s factories each month. Sixty-five Japanese cities had been reduced to ashes. The B-29 attacks had convinced everyone in Japan – except its deranged militarist rulers – that the war was lost.

Even kamikaze attacks against America’s huge, heavily armoured planes were largely ineffective; sometimes they appeared to just bounce off with barely a jolt. The B-29 programme had cost $4 billion, against $3 billion for Manhattan. Which way to go?


The army protested against over-reliance on bombing. Effective as it seemed, would bombing Japan be any more successful in shortening the war than bombing Germany? A nightmare scenario was predicted where the war would drag on, costing the lives of PoWs and forced labourers in the meantime.

The army view was forceful and seemed to prevail. Was the invasion on? The recapture of Burma by British and Indian forces in spring 1945 suggested Japan was on the retreat. Iwo Jima had been taken on 27 March, bringing the Americans within 700 miles of Japan.

The atomic explosion over Nagasaki,
9 August 1945.
The atomic explosion over Nagasaki, 9 August 1945.

But five weeks of heavy fighting had cost 24,000 US casualties, including over 7,000 dead, and all this ‘to capture an island one third the size of Manhattan’. Then came Okinawa. In Japan, the hope was that a negotiated peace could be won if the Americans were made to pay a heavy enough price for every gain.

Meanwhile, throughout June and July, the Russians moved troops, victorious over the Germans, eastwards across Asia, ready to join the war against Japan. Stalin promised an offensive against Manchuria in August, and US policy-makers seemed content to let him go for it, naively believing a Russian front would save US lives by transferring some of the bloodiest fighting to the Reds.

But Stalin was not interested in helping his allies: he had his own territorial gains in mind. Washington was muddled, Moscow as clear as ice.


Then came the first successful test of the atomic bomb in July 1945 at Alamagordo, christened ‘Trinity’ by Oppenheimer. This offered a third option: not endless bombing, not a murderous invasion, but something that might shock the Japanese into quick surrender. Some 125,000 scientists, engineers, and support staff had been labouring for this moment. But what should the target be?

Tokyo was rejected, as was the ancient capital of Kyoto. Hiroshima, not as badly battered as some Japanese cities by conventional US bombing, was selected as first target. Nagasaki eventually became target two, should the Japanese show any resistance to surrender.

Japan still had chances. During July they made tentative, largely incoherent noises about suing for peace. Something was afoot. However, the Japanese elite was not speaking with a single voice, messages were unclear, and they did not make any specific response to the Allied demand, agreed at Potsdam, that they should surrender immediately and unconditionally.

On 26 July, Truman, Churchill, and Chiang Kai-Shek again called jointly for Japan’s DESTROYER OF WORLDS 50 surrender. The alternative was spelled out as ‘prompt and utter destruction’.

It was clear what was planned, but to the Allies only. The Japanese assumed it meant more bombing, then invasion. Why would they think otherwise?


On the morning of 6 August 1945, three US B-29s appeared over Hiroshima. Two carried cameras and scientific equipment. It was for the Enola Gay to deliver the bomb.

Less than one minute after the plane’s bomb doors opened, most of Hiroshima vanished in a blinding light. As well as the immediate deaths, many more died later from the after-effects of radiation-poisoning, burns, and shock.

US Marines rest during the ferocious fighting on Okinawa, the first Japanese island to be invaded. How many would die in a land battle for the whole country?
US Marines rest during the ferocious fighting on Okinawa, the first Japanese island to be invaded. How many would die in a land battle for the whole country?

Mission commander Brigadier-General Tibbetts, 30, was a pilot of wide experience, and he gave the world a descriptive account of the morning that heralded the nuclear age.

Contrary to usual practice, it was deemed necessary for the plane to drop its payload and then take rapid abortive action, turning around and flying clear as quickly as possible. Tibbetts had been told to get away from the shock-wave coming back from the ground.

The risks were deemed high, so the weapon was not ‘armed’ until the plane was in the air and over the sea. The bomb-run was an unusually long 11 minutes to give the crew plenty of time to get everything right, including air speed.

It was a clear, sunny morning, with excellent visibility. Tibbetts confirmed that the bomb exploded 53 seconds after leaving the plane, which just gave time for the steep turn he needed to execute.

To Tibbetts, it felt as if someone had grabbed hold of his plane and given it a violent shake. That was the shock-wave.

There was a second shock, not quite as violent, after which the pilot turned back to take a look. The crew saw a cloud coming up. It was two minutes after, and the cloud had reached the plane’s altitude (33,000 feet) and was rising. The surface was described as ‘nothing but a black boiling, like a barrel of tar’. The city of Hiroshima had become a ‘black boiling debris down below’.


The same day, Truman announced that American and British scientists had developed the atom bomb, and that the first had been dropped. The new British Prime Minister Clement Attlee then issued a statement, prepared by Churchill prior to leaving office. Churchill pulled no punches. ‘It is now for Japan to realise, in the glare of the first atomic bomb that has smitten her, what the consequences will be of an indefinite continuance of this terrible means of maintaining a rule of law in the world.’

Truman warned Japan that failure to surrender would result in more of the same. In the meantime, Russia declared war on Japan (8 August), and commenced its invasion of Manchuria.

Nothing was heard from Japan, so Nagasaki was bombed just three days after the first strike, the day after the Soviet attack. Some 35,000 died.

 Victims of the Hiroshima bombing.
Victims of the Hiroshima bombing.

MacArthur requested a third bomb, but Truman refused, MacArthur eventually being sacked. The Russians piled 1.5 million troops into the fray, supported by 5,500 tanks, another demonstration of irresistible force.

The shock of mass carnage brought the Japanese emperor, Hirohito, round. The US justified its actions in a shock-horror prediction of how much worse an invasion of the Japanese mainland would have been than Okinawa – a battle that had seen 25% of all civilians on the island killed. If that scale of loss had been repeated, then Japanese deaths would have far exceeded those consumed by the two atom bombs. That was how the argument ran.

There was more. With Stalin’s forces now moving across the Manchurian frontier and threatening the Western Allies’ plans for the post-war world, Truman and his cohorts surely wanted to demonstrate to ‘Uncle Joe’ the capability they now possessed. This may not have been the decisive factor, but it was a factor. So, too, was the need to bring the war to a speedy conclusion before the Red Army could make further gains.


After the collapse of Germany in May, the Japanese had been left without allies, and all British and US resources in men and material could be redirected to the Pacific theatre. Japanese strength was arguably half-broken and Japanese morale was disintegrating when the blows came. Was the atom bomb really necessary to finish them off? The debate still rages.

Astonishingly, for some days, the surrender did not come and conventional bombing of Japan continued. Only on 10 August did the Japanese cabinet decide to make an offer of surrender, provided Emperor Hirohito could remain; the Allied terms, including this assurance, were immediately communicated to Tokyo.

The crew of the Enola Gay, which dropped the ‘Little Boy’ on Hiroshima.
The crew of the Enola Gay, which dropped the ‘Little Boy’ on Hiroshima.

It took until 14 August for the terms to be accepted, and for the Emperor to announce that Japan would comply with the Potsdam Declaration and that he would broadcast to the nation. The recorded message was transmitted at noon on the 15 August.

This gave the Americans time to launch one last post-Nagasaki fire-bombing, with 800 B-29s attacking Isesaki. Hirohito then called on all Japanese forces to surrender, backing up his order with the absurd understatement that the war situation had developed ‘not necessarily to Japan’s advantage’. The submission was the signal for some Japanese officers to commit hara-kiri, and for one last round of kamikaze attacks.

US forces of occupation landed in Japan on 26 August to occupy strategic centres, but Japan’s formal surrender did not occur until 2 September, the scene being played out on the USS Missouri in Tokyo Bay, where the signing was completed by Japanese civil and military envoys.

The Japanese home islands were placed under the rule of a US army of occupation, but the Emperor remained as head of state. Japanese political and police officials continued to fulfil their functions while the high command and infrastructure of the Imperial Japanese military were systematically dismantled.


The war was over, but the debate about the righteousness of using the Bomb was just beginning. Critics of its use tend to ignore the fact that prisoners and slaves of Japan continued to die in their thousands each day, as long as the war continued, and that Japan’s militarist elite was exceptionally brutal and stubborn.

Why, though, did the Allies not categorically deny that they would invade Japan, declare that ‘Olympic’ was off, and state that their plan was to starve and bomb the Japanese into submission? Why, for that matter, did Truman not issue an explicit ultimatum before unleashing the Bomb? That one omission has done more damage to his reputation than anything else.

The surrender ceremony: the Japanese delegation arrives on board the USS Missouri, lying at anchor in Tokyo Bay, on 2 September 1945.
The surrender ceremony: the Japanese delegation arrives on board the USS Missouri, lying at anchor in Tokyo Bay, on 2 September 1945.

A prompt Japanese surrender may not have been forthcoming, as Hirohito did not have the power to make the decision alone, needing a consensus in the Japanese Cabinet, but at least the US leadership would have tried.

Churchill spoke of ‘awful agencies’ that he hoped would bring peace rather than destruction. Seventy years on, we have been lucky so far, but for how long?

The Russian ‘Tsar Bomba’, detonated in October 1961, was reputedly 1,400 times more powerful than ‘Little Boy’ and ‘Fat Man’ combined, although it is said that the decommissioning of warheads has left nothing of this scale extant. It is a sobering thought, however, at a time when North Korea’s ambassador to the UK has warned that his country would be prepared to use nuclear weapons and has the capability to launch a deadly warhead ‘any time’.

This is an article from the August 2015 issue of Military History Matters. To find out more about the magazine and how to subscribe, click here.

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