Questions About Hiroshima Persist – Reconsidering Obama’s “Apology” and Truman’s Claim that Hiroshima was a Military Target


It is one thing for the President of the United States to go to Hiroshima, his presence a kind of apology for the US atomic bombing of that city, and of Nagasaki.  But was Truman right when he said Hiroshima was a military target?  And if he was, then Obama was wrong, even if his apology was banal and indirect.

But there are questions about the use of the atomic bomb that still cause great unease. The official explanations, that the atomic bombing was intended to end the war with Japan and to spare American and allied lives, does not seem convincing.

Dr. Bunsaku Arakatsu 

Dr. Bunsaku Arakatsu

We know that General Eisenhower was consulted about the use of the atomic bomb on Japan and he was against it. And we know that, at least officially, General Douglas MacArthur was not asked for his opinion, or even told about the operation, though this is hard to believe. (Later Macarthur wanted to use atomic bombs in Korea, more than 20 of them. He was no shrinking violet when it came to atomic weapons.)

But at the top levels of the Truman administration, and at the top levels of the Manhattan Project (meaning Brigadier General Leslie Groves and Robert Oppenheimer) there was urgency to use the bombs before the war was over. The Los Alamos team had already missed their chance in Europe, because the Germans surrendered. Now, with little time left, the decision was made to go ahead.

Technologically it was an interesting decision. The first bomb to be used, the one that devastated Hiroshima, was a uranium bomb (code named Little Boy), meaning that the chain reaction and subsequent explosion took place in a gun type chamber. This bomb required highly enriched uranium (HEU) and Oak Ridge, where HEU was being processed was well behind in meeting the Project’s needs. With a shortage of HEU, and some partly enriched uranium already diverted to Hanford for the special nuclear reactor there that would produce plutonium, the situation was very tight. The uranium bomb was never tested like the plutonium bomb that was exploded in a test at Alamogordo. Called the Trinity Test, the plutonium bomb, the test model called the Gadget, required a complex, exquisitely timed mechanism to set off the fissile material. While the Gadget worked in the test, whether it would function in real life conditions, bouncing around in a B-29, was still an open question. So Hiroshima got the only uranium bomb there was.

The atomic bomb test at Alamogordo was on July 16. The Hiroshima bombing was on August 6. On August 7th, 16 hours after the bombing of Hiroshima, President Truman called for Japan’s unconditional surrender, consistent with the earlier Potsdam declaration. Late in the evening on August 8, Russia declared war on Japan and its forces attacked Japanese controlled Manchuria and Korea. On August 9 a plutonium atomic bomb, code named Fat Man, was dropped on Nagasaki. On August 15, with Russia no longer a possible interlocutor for a Japanese peace delegation, Japan surrendered.

While the atomic bombing helped Japan decide to surrender, most experts today think it was Russia’s declaration of war on Japan that was decisive because it cut off any possible avenue for the tottering regime in Tokyo to try to bargain with the United States.

We know that Japan took a little time to fully comprehend the atomic bombing of Hiroshima. Firstly, the devastation was such that there were no communications back to Tokyo and thus no information either on the bombing or what was destroyed. With communications down, a few days after the bombing Tokyo sent scientists to Hiroshima. Included were the top scientists of RIKEN, the world famous institute in Tokyo. RIKEN was heading up one of Japan’s two known atomic bomb projects. In the case of RIKEN the project was managed by the Army and headed by a top physicist named Dr. Yoshio Nishina. Nishina had strong connections to German physicists and chemists and worked in the 1930’s with Niels Bohr, the Danish physicist who would later get smuggled out of Denmark and work on the British Tubes Alloy program, the code-name for Britain’s atomic weapons research program. The Army-run program was known as Ni-Go.

Nishina was dispatched to Hiroshima, and he took with him a team of experts whose job it was to find out whether it was an atomic bomb that struck the city, and to figure out the amount of destruction and the technical characteristics of the bomb. They had little trouble confirming their worst fears; but they took advantage of the emergency visit to the city to make many measurements. They were especially interested in understanding the altitude the bomb was exploded, and apparently they were able to figure this out with some degree of accuracy.

One can ask, what conceivable reason would Nishina and his team want to know about the altitude the weapon was exploded?

The other atomic bomb development program was called F-Go and was headed by another talented physicist, Dr. Bunsaku Arakatsu. He had been a student of Albert Einstein, so he needed no special help in understanding the physics of an atomic bomb. From what can be determined, Arakatsu concentrated on manufacturing enriched uranium using ultra-centrifuges. The design of the Arakatsu centrifuge is now known, as blueprints have been found. Operating faster than contemporary centrifuges, the design is efficient and the output would have been adequate provided the goal was to produce a plutonium bomb. The centrifuge was planned to go into serial production, manufactured by Tokyo Koecki, around August 1945.

Plutonium is produced in a nuclear reactor, sometimes referred to as a nuclear pile. Japan may have built a reactor in Konan, Korea where uranium was also being extracted and where heavy water production was apparently underway. Heavy water is a neutron moderator in a reactor.

In 1946 David Snell, a reporter for the Atlanta Constitution, was assigned to the 24th Criminal Investigation Detachment of the US Army of Occupation in Korea. He interviewed a Japanese war prisoner who was said to be a Japanese counterintelligence officer on his way to being repatriated to Japan. According to the Japanese officer, Japan had already tested two small atomic devices, one in Korea and the other in Manchuria. The real goal was a larger size bomb, on the order of the Hiroshima one. It was called by the Japanese Genzai Bakudan, Greatest Fighter. Its purpose was to force a surrender deal favorable to Japan and, in particular, to the Emperor.

It is impossible to write off the Snell story, or the industrial infrastructure that existed on the Japanese mainland and in Korea. Snell’s reporting and his story was, of course, denounced by the US government as untrue. Arakatsu and Nishina and many other Japanese scientists involved in the atomic program claimed they were very far behind and never had enough funding or government support for an atomic bomb. This was the party line at the end of World War II and it has remained so ever since.

But there are many disquieting facts that keep alive the alternative narrative that Japan was very close to having an atomic bomb and the reason behind US urgency to drive Japan to surrender unconditionally was fear that Japan would have an atomic bomb and might use it, either against the invasion fleet, or even against an American city.

Is there any evidence for the alternative narrative? The answer is there is circumstantial information that suggests that Japan’s atomic program was a very high priority for the United States, and it is quite possible that more was known about what was happening in Japan then we have been told.

Perhaps the most important is the fact that the US was going all out to stop the transfer of atomic technology from Germany to Japan. By late in the war, shipments of these materials, that included uranium (in the form of uranium oxide, possibly uranium metal and possible enriched uranium), heavy water and other materials for nuclear reactors, went by submarine to Japan. Some of the submarines were Japanese; some German U-boats and some Italian ones. The US tracked these subs, and their cargoes, thanks to intercepts of coded messages. Every effort was made to destroy them before they reached their destination, and many were thus destroyed. What we don’t know is how many successful voyages took place.

If Japan did not have an atomic program of any great importance, using scarce assets to chase these cargo subs would not have the priority it received.

The case of U-234 is also important to the alternative narrative.


U-234 surrenders.  Note the American flag flying from the mast of U-234.

Obeying a directive from Berlin after Germany surrendered, U-234 surrendered to the USS Sutton off the coast of Newfoundland. Among other goods, U-234 was carrying 540 KG of uranium in special casks that were inserted in tubes that had been converted for the purpose of carrying the uranium. The sub was escorted to Portsmouth. The uranium cargo was inspected on land, then apparently shipped first to Washington and subsequently to Oak Ridge. Moreover, the fact that the cargo included uranium was classified. One of the German sailors believes he saw Robert Oppenheimer when the casks were inspected. He did not know who Oppenheimer was at the time, but Oppenheimer was an unusually thin man, often seen wearing his trademark Pork Pie hat. Later, learning of Oppenheimer’s role in the Manhattan program, he made the connection.

The type of uranium on board U-234 has always been disputed. But if it was uranium that was partially enriched, the message to Oppenheimer and Oak Ridge, and to General Groves, head of the Manhattan Project, would be that Japan was close to having either a uranium or a plutonium bomb. Was there evidence that some of the infrastructure for Japan’s bomb program was in Hiroshima, a city that was not on the original target list? Or in Nagasaki?

Even more worrisome would be if Japan had already received nuclear material from Germany, something that the allies may already have known. The thousands of intercepts or Ultra and other materials still remain, for the most part, under wraps.

Thus following an alternative scenario, in May the US atomic bomb team may have thought they were in a race with Japan for an atomic bomb. What they probably missed, and which could have been a major intelligence failure, was that a significant share of Japan’s program was on the Korean peninsula and no on the Japanese mainland. Or perhaps they knew that, but felt the priority was where Genzai Bakudan was going to be assembled?

No matter which narrative one accepts, these and many other lingering questions remain unanswered. By filling in what is missing perhaps we can understand better the decision-making leading up to August 6, 1945. Truman’s insistence, that never varied, that Hiroshima was a military target may turn out to be the truth. Historians of the period may need to rethink everything. The President’s quasi apology this year, 2016, would turn out to be completely inappropriate.


* Dr. Stephen Bryen is the author of Technology Security and National Power: Winners and Losers (Transaction Publishers).  This essay is based on section of the book and the full documentation can be found there.  The book is available from booksellers worldwide.

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