THE HONORARY ARYAN BRETHREN
Contrary to the widely held view, the United States may have known about the Japanese project before the end of the war, and this information might have influenced President Harry Truman's decision to use the bomb on Japan.
... when UN forces had been at Hungnam in connection with the retreat from Chosin, a mysterious installation in the mountains around it had been discovered.
~Robert K. Wilcox, Japan's Secret War: Japan's Race against Time to Build is Own Atomic Bomb
An ancient Japanese legend has it that the Japanese people are descended from a blonde haired blue eyed race that came from the stars, a legend remarkably similar to the doctrines that percolated in the secret societies that fostered and mid-wifed the Nazi Party into existence in Germany between the World Wars. Nor did this legend play a small part in the history of World War Two, for it was partly because of its mere existence that Hitler could proclaim the Japanese "honorary Aryans" and conclude the incorporation of Japan into the Rome-Berlin-Tokyo Axis without contradicting Nazi Party racial ideology. This was in no small part due to the Japanese ambassador in Berlin's diplomatic skill in pointing out this little known fact of Japanese legends to the Germans. Of course, there were pressing military and political reasons for Italy and Germany to conclude an alliance with Japan, but for the race and ideology obsessed Nazi government, so much the better if the Japanese had some sort of Nordic-Aryan connection, no matter how tenuous that might be. An early and continuous problem for the three Axis partners was to arrange the transfer of technology and raw materials from Europe to the Far East. Most transfers occurred via U-boats or Japanese submarines, though both Germany and Italy undertook long range, and militarily quite risky, flights to Japan as well.
The Italians, for example, mounted such a flight with a Savoia Marchetti S 75 GA during 1942, ostensibly for the purpose of supplying the Italian embassy in Tokyo with copies of new Italian code books, since the Commando Supremo had concluded that the Allies had broken Italian codes. [Dr. Publio Magini, Military History Quarterly, Summer 1993].
As the war progressed, the Germans found themselves increasingly trading their high technology for very little in return other than the prospect of stiffening Japanese resistance and perhaps drawing American force to the Pacific and lessening pressure on the Reich. And the Japanese, their industry hard-pressed to maintain pace with American and British technological developments, were always very eager, and very specific, in their demands for high technology from their Aryan brethren.
Even the conventional military technology transfers from Germany to Japan are staggering enough.
By 1944 Japan had requested and received either working models or full production designs for the following:
German techniques for manufacturing cartridge steel for large gun barrel linings;
Finished artillery pieces;
105 and 128 mm heavy anti-aircraft (FLAK) guns;
the 75 and 88 mm field pieces and anti-tank guns;
the Würzburg radar system;
750 ton submarine pressure hulls;
the PzKw V Tiger I tank;
the Focke Wulfe 190 fighter;
the Henschel 129 tank-busting aircraft [This rather odd-looking twin engine aircraft had a bulbous cupola slung beneath the nose of the main fuselage, in which was mounted a 75mm automatically reloading high velocity anti-tank gun projecting from its nose. It was a deadly and efficient tank-busting airplane used with great effectiveness on the Eastern Front, curiously resembling a similar ground assault aircraft in the modern American arsenal, the A-10 "Warthog"];
the Heinkel He 177 heavy bomber;
the Messerschmitt 264 long-range Amerikabomber;
the Messerschmitt 262 jet fighter;
the Messerschmitt 163 rocket-powered fighter;
the Lorenz 7H2 bombsight; the B/3 and FUG 10 airborne radars;
and perhaps significantly, Twenty-five pounds of "bomb fuses.
~ Joseph Mark Scalia, Germany's Last Mission to Japan: The Failed Voyage of the U-234
Fortunately for American and Commonwealth forces in the Pacific theater, these weapons never saw full scale production by the Japanese. What is intriguing is the last item. Why bomb fuses? Surely the Japanese, who had been raining bombs all over China, Indochina, Burma, and the Pacific knew how to fuse a conventional bomb. The request suggests that the fuses were of a sophistication beyond the capabilities of Japanese industry. And why a request for heavy bombers so close to the end of the war, at least one of which was reputedly capable of ultra-long-range flight and heavy payload?
A. Strange Rumors
As with the end of the war in Europe, the end of the Pacific war carried with it the odd rumor or two, some of which managed to appear in short articles in the Western Press, before the curtain of the Allied Legend slammed down to hide their implications from view. Robert K. Wilcox, in a book that may well in retrospect be the first book on the German bomb project from a revisionist perspective, Japan's Secret War, revitalized these reports and rumors:
Shortly after World War II had ended, American intelligence in the Pacific received a shocking report: The Japanese, just prior to their surrender, had developed and successfully test-fired an atomic bomb. The project had been housed in or near Konan (Japanese name for Hungnam), Korea, in the peninsula's North. The war had ended before this weapon could be used, and the plant where it had been made was now in Russian hands.
By the summer of 1946 the report was public. David Snell, an agent with the Twenty-fourth Criminal Investigation Detachment in Korea... wrote about it in the Atlanta Constitution following his discharge.
Snell's source for the allegation was a Japanese officer returning to Japan. The officer informed him that he had been in charge of security for the project. Snell, paraphrasing the officer in his article, stated:
In a cave in a mountain near Konan men worked, racing against time, in final assembly of "genzai bakudan," Japan's name for the atomic bomb. It was August 10,1945, only four days after an atomic bomb flashed in the sky over Hiroshima and five days before Japan surrendered.
To the north, Russian hordes were spilling into Manchuria. Shortly after midnight of that day, a convoy of Japanese trucks moved from the mouth of the cave, past watchful sentries. The trucks wound through valleys, past sleeping form villages.... In the cool predawn, Japanese scientists and engineers loaded genzai bakudan aboard a ship at Konan.
Off the coast, near an islet in the Sea of Japan, more frantic preparations were under way. All that day and night, ancient ships, junks and fishing vessels moved into the anchorage.
Before dawn on August 12, a robot launch chugged through the ships at anchor and beached itself on the islet. Its passenger was genzai bakudan. A clock ticked.
The observers were 20 miles away. The waiting was difficult and strange to men who had worked relentlessly so long, who knew their job had been completed too late.
The light in the east, where Japan lay, grew brighter. The moment the sun peeped over the sea there was a burst of light at the anchorage, blinding the observers, who wore welder's glasses. The ball of fire was estimated to be 1,000 yards in diameter. A multicolored cloud of vapors boiled toward the heavens, then mushroomed in the atmosphere.
The churn of water and vapor obscured the vessels directly under the burst. Ships and junks on the fringe burned fiercely at anchor.
When the atmosphere cleared slightly the observers could detect several vessels had vanished. Genzai bakudan in thut moment had matched the brilliance of the rising sun to the east. Japan had perfected and successfully tested an atomic bomb as cataclysmic as those that withered Hiroshima and Nagasaki.
There are a number of things to note about this account. How had Japan, hard-pressed for even conventional military technology, pulled off this feat of testing an atom bomb of the same approximate yield as Hiroshima and Nagasaki? Where did they get the enriched uranium for the weapon? Moreover, the Japanese had tested their bomb only three days after the plutonium "Fat Man" fell on and obliterated Nagasaki. Small wonder then, that the Japanese cabinet debated whether or not to surrender. This important fact, in conjunction with Wilcox's startling revelations, will serve as the basis for further speculation in a moment. Finally, the test itself suggested that the Japanese envisioned deploying the weapon against naval targets. What possible thoughts may have been going through the Japanese cabinet's surrender debate? Possible clues lie in the nature of the Japanese program itself, and its significant reliance on technology transfers from Germany.
The chief physicist involved in the Japanese project was Yoshio Nishina, a "colleague of Niels Bohr." It was Nishina who in fact headed the Japanese army team that investigated Hiroshima after the bombing of that city. The reports of the Japanese test at Konan were a steady source of consternation and mystification to American intelligence units in occupied Japan after the war, for unlike its obsession with the German bomb program, Allied intelligence consistently placed the Japanese far behind, as conducting only theoretical studies, and maintaining that the Japanese "had neither the talent nor the resources to make a bomb." Resources Japan may have lacked, but there was no lack of talented physicists who understood bomb physics. In any case the reports caused enough concern tor the American occupying forces to send several intelligence teams throughout Japan to destroy its cyclotrons, of which there were no less than five, and presumably more! This curious fact raises a question. What were the Japanese doing with that many cyclotrons? Could they have perhaps been given the secrets of Baron Manfred von Ardenne's method of mass spectrograph separation and enrichment of uranium 235? Or did the Japanese physicists, like their German and American counterparts, come to the realization that the cyclotron afforded a method for isotope enrichment? Both are possible, and the latter is probable.
B. Strange Industrial Complexes:
Kammler Revisited, Noguchi Style
Further confirmation of a Japanese atom bomb test led Wilcox to connect Nishina to a Japanese industrialist named Noguchi. Searching through American declassified records, Wilcox quickly concluded that "subsequent directives in the same boxes ordered reinvestigations in 1947 and 1948 of Japanese wartime atomic research, indicating that (American intelligence) still did not know exactly what had happened. In fact, (it) was continually ordering reinvestigations of Japanese wartime atomic research and discovering new facts at least up until 1949, according to additional documents that I found." Then Wilcox struck a very rich vein: Box 3 of Entry 224 yielded a high mark of my two days at Suitland [Suitland" is Wilcox's nickname for the US National Archives] In interrogation of a former engineer at the Noguchi Konan complex, Otogoro Natsume, conducted on October 31. 1946 "Subject" of the interrogation was listed as "Further questioning the newspaper story about atomic bomb explosion in Korea."
In attendance were head (sic) of the Science and Technology Division, Dr. Harry Kelly; an interpreter, "T/4 Matsuda," and a "Mr. Donnelly," identified only as "5259 TIC." He apparently was some sort of intelligence officer and, judging from their questions, the interrogators had more information about the Konan-Hungnam story than was in the newspaper.
Natsume, a chemical engineer, according to the interrogation, had been imprisoned by the Russians and then released to run a Konan plant until he escaped "on a small sailing boat" in December 1945. He told the investigators he'd heard the rumors about the atomic bomb explosion at Konan but knew nothing about it. According to the transcript, the following exchange then ensued:
Kelly: "Did any of the plants have accidents during the war?"
Donnelly: "We haven't actually found anything concrete. Last few days we have been talking with people here in and around Tokyo and asking them about report(s) of decomposition of hydrogen peroxide and asking them if they knew about it or which plant it was."
Kelly: "Did any of the plants have accidents during the war?"
(Natsume through Matsuda): "There were none."
Donnelly: "Ask him if he knows anything about the NZ plant making hydrogen peroxide." Matsuda: "He says that he heard about the factory but it was under the Navy and highly secret. He had never been in it."
Kelly: "What was the name of the plant?"
Matsuda: "He says just NZ plant."
Donnelly: "Ask him what NZ plant made and what does NZ mean?" Matsuda: "He doesn't know." A few more questions about the ownership and location of the plant, then:
Kelly: "About how many chemists worked up there?"
Matsuda: "He says there are so many classes of chemists. Do you mean University Graduate?" Kelly: "yes." Matsuda: "He says that there are two factories under management of this company - one in Konan and one in Honbu. There are about 700 chemists altogether (approximately 300 at Konan)."
In a lengthy exchange, Natsume indicated that most of the scientists, engineers, and workers at Konan were arrested and then later released to go back to work. But six key technical people from NZ, whom he later named, were not released and he had "no idea" what the Russians were doing with them except they were being held in the "secret plant."
Has he got any idea as to how we can get these secret plans?
The six men mentioned are the only ones who knew much about the secret plant.14
As we shall see momentarily, perhaps the most significant thing about this interrogation is the date, October 31, 1946. It is also significant that the bulk of the scientists involved appear to have been chemists. Finally, as is apparent from the interrogation, the plant or plants at Konan were of significant size.
So what was the Konan complex? To reconstruct it requires a similar process to that used in examining the German uranium enrichment program. The transcript connects the Konan complex and a Japanese industrialist named Noguchi.
Jun Noguchi had built the huge Japanese complex of factories that nestled about the Yalu, Chosin, and Fusen rivers. The latter two rivers had been dammed by Noguchi to supply the enormous electrical power needed by his factories. "Together the three rivers delivered more than 1 million kilowatts of power" to the complex. This was for the time a prodigious amount of electricity, especially in view of the fact that all of Japan produced no more than 3 million. Begun in 1926 in a deal struck with the Japanese Army Noguchi's Konan empire expanded along with Japan's imperial appetites.
So, like the I.G. Farben "Buna" plant at Auschwitz, we note already two key ingredients are present at Konan: large electrical power production infrastructure, and proximity to large amounts of water. Konan, in fact, was the largest industrial complex in all of Asia, and relatively sheltered and even unknown to Allied bomber and the intelligence committees that prepared their targets lists. But there is more.
Declassified documents noted that Konan was also near uranium ore deposits. "This was the logical place for an end-of-the- war atomic bomb project." Moreover, as Wilcox discovered, "More digging...turned up a lengthier summary." Dated May 21, 1946 and originating within the US Army's chief of staff office in South Korea, it stated:
Of increasing interest have been recent reports dealing with an apparent undercover research laboratory operated by the Japanese ... at ... Hungnam.... All reports agree that research and experiments on atomic energy were conducted.... The two chief scientists were Takahashi, Rikizo and Wakabayashi, Tadashiro.... The recent whereabouts of these two individuals is not known, inasmuch as they were taken into custody by the Russians last fell. However, before their capture they are reported to have burned their papers and destroyed their laboratory equipment.... Some reports... say... the Russians were able to remove some of the machinery. Further reports stated that the actual experiments on atomic energy were conducted in Japan, and the Hungnam plant was opened for the development of the practical application of atomic energy to a bomb or other military use. This section of the ... plant ... was always heavily guarded.... These reports received separately are surprisingly uniform as to content. It is felt that a great deal of credence should be attached to these reports as summarized.
We may now speculate as to the real significance of these US Army intelligence reports in the light of subsequent events.
Clearly, the US Army is taking seriously allegations of a Japanese atom bomb project based in the northern Korean Peninsula, very close in fact, to the international border with China, and scene of one of the Korean War's bloodiest battles. At the Chosin Reservoir, General of the Armies Douglas MacArthur had been dealt a significant defeat and was forced to retreat. Indeed, after his celebrated landing at Inchon, MacArthur had relentlessly driven his troops northward in a classic Blitzkrieg style campaign, designed in part to seize the Yalu River crossings, crucial to any further operations in China, as well as for defense against any Chinese invasion of the peninsula. And the Chosin Reservoir, and hence Noguchi's vast Konan complex, was also a prime military target. With MacArthur's insubordination and the subsequent Chinese entry into the war, Truman fired MacArthur. So goes the standard history.
But could the real motivations for MacArthur's lightening dash up the peninsula toward Chosin after the Inchon landings in fact have been based on a very different, and highly secret, agenda of military objectives? Given the US Army's own intelligence memoranda concerning the Konan complex and Russian activities it seems all too likely. And this in turn may mean that the real motivations for his subsequent firing by Truman may also lie in what he uncovered there: certain knowledge of the extent, capabilities, and actual achievements of the Japanese scientists and engineers working on the genzai bakudan.
But what would have been so sensitive about the Japanese atom bomb project, beyond its actual achievements? To answer this question, we must speculate once again. What isotope separation and enrichment methods were known to the Japanese? What did physicist Nishina and his team of scientists finally rely on? Like them German counterparts, the Japanese knew that the ultra-centrifuge was the simplest path, at least in theory, toward the uranium bomb. But Japanese scientists calculated the needed revolutions-per-minute of such a device to be between 100,000 and 150,000 rpms. The United States itself, because of the difficulties in designing turbines of this speed, decided to forego enrichment via this 20 process.
At this point, Wilcox's reconstruction begins to run into a bit of trouble, for the Japanese, he reports, were able to design, and apparently to build, a large ultra-centrifuge. Their only problem, according to Wilcox, was a large enough supply or uranium. However, there is a significant weakness in this construction, for the Japanese, it will be recalled, had to request German assistance in the design and production of jet engines, a request that led not only to the exchange of blueprints for the Messerschmitt 262, the world's first operational jet fighter, but of technicians able to show the Japanese the necessary production methods and tolerances to construct such high speed turbines operating under the stress of tremendous heat. In other words, while Japanese theoretical capabilities were not lacking at that time, they did lack certain industrial expertise which only the Germans possessed. Moreover, as we have already seen, the centrifuge idea had originated and ben developed by the Germans. So if the Japanese successfully designed and built a large ultra-centrifuge, it would seem likely that German assistance was involved at some point.
The other method, a cheaper method and certainly one well within Japanese wartime industrial capability, and one taken to extremely large size by them, was very much a German device.
What the Nishina group finally did settle on was a process called thermal diffusion. This had been one of the first isotope separation processes devised. But until it was perfected by two German scientists, Klaus Clusius and Gerhard Dickel, in 1938, it had not been practical. Stated simply, thermal diffusion relied on the fact that light gas moves toward heat. Clusius and Dickel constructed a simple device consisting chiefly of two metal tubes placed on inside the other. The inner tube was heated; the outer one was cooled. When the apparatus was turned on, the lighter U-235 moved to the heat wall; the U-238, to the cold wall. Convex currents created by this movement sent the U235 upward; the U-238 downward.... At a certain point the U-235 at the top could be collected, and new gas pumped in. it was a simple and rapid way to get relatively large concentrations of U-235. As Wilcox notes, this process, developed as it was in Germany, gave the Japanese access to the latest development of this simple and unusual technology. And as we have already seen, the Germans also deliberately fabricated an alloy - Bondur - to offset the highly corrosive effects of uranium gas.
Used in large size and enough quantity - At Auschwitz and Konan - and perhaps in conjunction with other technologies of enrichment, von Ardenne's mass spectrograph adaptations of cyclotrons, it is entirely feasible that the Japanese also had a highly secret uranium enrichment project being run near the Konan complex. So one may advance the line of speculation further: with the surrender of the U-234 and its cargo of infrared proximity fuses and their inventor, Heinz Schlicke, and Japan's own request for "fuses" and plans for German strategic heavy bombers, MacArthur's troops at the Chosin Reservoir may have uncovered not only evidence of Japanese progress and eventual testing of a uranium atomic bomb but they may have uncovered further evidence of the success of the program that lay behind it: Nazi Germany's. Indeed, the fuses point to a possible plutonium bomb project underway in both countries.
And so we return to the decision of the Japanese cabinet, and speculate further. If the Japanese government knew of the German program, they may also have known of the extent of its success Two bombs had fallen, and according to the translator for Marshal Rodion Malinovsky, another had fallen but not detonated. In any case, the Japanese were probably aware that while America's single bomb project may not have been capable of delivering more bombs within a short span of time, there would have been no way to estimate how many bombs might have been taken as war booty from the Germans. And the failure of the U-234's mission would have told them that at the minimum, fuses capable of use in a plutonium bomb as well as a large supply of enriched uranium had fallen into Allied hands. By August 12, 1945, with the successful test of the Japanese bomb and the German test of October 1944. the war had gone nuclear.
Thus, if the Japanese had been informed of the successful test of the German atom bomb in October of 1944, then the debate of the Imperial Cabinet in Tokyo is understandable. Japan was faced with a potential rain of atom bombs "of German provenance," to quote Oppenheimer's curious remark once again. Surrender, ganzai bakudan notwithstanding, was the logical choice, even for a nation steeped in "proud samurai traditions of honor."
In this light, perhaps the most significant fact uncovered by Wilcox is that "contrary to the conventional military history that Japanese atomic efforts were bombed into extinction by spring 1945... the project was continued and heightened even after the Emperor's August 15 surrender." Wilcox does not elaborate much farther than this, but the statement raises a chilling prospect:
How could a Japanese project survive right under the noses of the occupying American forces? ... and what if it was not only the Japanese project that survived?
Japanese atomic program
The Japanese atomic program was a program by the Empire of Japan to develop a genshi bakudan (sometimes incorrectly called genzai bakudan), an atomic bomb during World War II. The program started around the same time as the U.S. Manhattan Project. Most experts believe that the program was small, and managed neither to refine enough uranium-235 nor to breed enough plutonium needed to make a workable device. The surrender of Japan on August 15, 1945 halted all developments before Japan could finish developing the weapon.
Atomic program of the Japanese Army Air Force
During the 1930s, the scientific community in the world started to understand the power of nuclear energy, and the Empire of Japan, like many other governments, was made aware of the possibility of developing a weapon which utilized nuclear fission as the source of its energy. The central figure of the Japanese atomic program is Dr. Yoshio Nishina, who also was a friend of Niels Bohr, and a close associate of Albert Einstein. Dr. Nishina was a highly skilled world class scientist with excellent leadership qualities. He also co-authored the Klein-Nishina Formula, and the Nishina crater on the moon is named after him.
Dr. Nishina established his own Laboratory at the Riken (the Institute for Physical and Chemical Research) in 1931 to study high-energy physics. He built his first 26 inch cyclotron in 1936, and another 60 inch 220 ton cyclotron in 1937. In 1938 Japan also purchased a cyclotron from the University of California, Berkeley.
Dr. Nishina knew and understood the military potential of nuclear weapons, and was worried that the Americans were working on a nuclear weapon, which could be—and eventually was—used against Japan. About the same time, in 1939, President Franklin D. Roosevelt started the first investigations into fission weapons in the United States, which eventually evolved into the massive Manhattan Project (the very laboratory from which Japan purchased its own cyclotron would become one of the major sites for weapons research). Dr. Nishina, a patriot for his country, tried to match the U.S. research, and promoted the development of a nuclear weapon. In October 1940, Lt. General Takeo Yasuda of the Japanese army finally decided that such a weapon was feasible and practical, and the Japanese atomic program started in July 1941 under the guidance of Dr. Nishina.
Atomic program of the Japanese Navy
A separate atomic program of the Japanese navy was also in progress in 1942. This project, called F-Go, was headed by Prof. Bunsaku Arakatsu, a lecturer at the Kyoto University, who studied under Albert Einstein. Arakatsu built his own cyclotron. His team included Hideki Yukawa, the first Japanese physicist to receive a Nobel Prize in 1949.
The program of the Navy initially aimed only to harness nuclear energy as an energy source to reduce the dependence on oil and to relieve the permanent shortage thereof, as it was thought that a weapon would not be able to be developed for wartime use (in this respect, it was very similar to the German nuclear energy project going on at the same time). However, as the tide of the war turned against Japan, the goal of making a nuclear weapon became a priority. The Japanese Navy launched a search for uranium throughout the dwindling empire. The Japanese military took what Nishina had learned and expanded the program, for instance, building five improved gaseous diffusion separators based on the smaller, single unit developed in Nishina’s effort. What happened to the separators, described by Col. Tatsusaburo Suzuki, who coordinated the effort for the army, is not known. But the Navy lacked time and material and despite paying huge amounts for uranium on the Chinese black market and arranging for Nazi uranium to be shipped by submarine, the navy did not produce a nuclear weapon. Exactly how far the Navy project got is a matter of debate.
The Japanese programs' source of uranium ore was Korea, which had been under Japanese control since 1905. Dr. Nishina investigated a number of methods for enrichment of uranium, and decided that the gaseous diffusion method would be most worth pursuing. However there is no evidence that production plants of the size used by the Manhattan Project were ever constructed, and the Manhattan Project plants, for all of their vastness, were only able to produce enough material for three bombs by the war's end.
Japan disclosed its program to its ally Germany, and requested assistance. It is not known how much material Japan received from Germany, but at least one shipment that was sent to Japan by a German submarine was intercepted.
This submarine, Unterseeboot 234 (U-234) was sent to Japan in 1945 to deliver 560 kg of uranium for the Japanese program, as well as a disassembled Me-262 jet fighter and V-2 rocket parts (which would have been of little use for a primitive nuclear weapon). Two Japanese military officials and a number of German experts were also on board. The nuclear cargo was labeled "U-235," perhaps as a mislabeling of the submarine name, or perhaps in reference to the fissile isotope of uranium, uranium-235. It is extremely unlikely, though, that it was truly 560 kg of uranium-235—this would have been some eight times more of the rare element than was produced by the entire U.S. effort, and enough for Nazi Germany to have built many atomic bombs of their own with great ease. It is more likely that the uranium was un- or partially-enriched uranium oxide (which naturally has over 99% uranium 238). The submarine was ordered to surrender on May 10, 1945, two days after the overall German surrender, by Admiral Dönitz. To avoid capture, the two Japanese officials, Lieutenant Commander Hideo Tomonaga and Lieutenant Commander Genzo Shoji, committed suicide and were buried at sea the next day. The submarine was boarded by US forces on May 14 and the cargo fell into U.S. hands.
Some reports claim that the 560 kg of uranium oxide was enough to build two atomic bombs, but this would mean that it was substantially enriched (and would have also meant that Germany could have developed its own bomb with it, which it did not). That amount of unenriched uranium, if enriched to around the 90% needed for an atomic bomb, would provide around 4 kg of bomb-grade material, far less than needed for an atomic bomb (the "Little Boy" uranium weapon dropped on Hiroshima used over 60 kg of uranium-235). If put into a reactor, however, it could have potentially been used to breed plutonium, perhaps enough to use for a weapon if the program had been larger.
American bombing raids disrupted the development of the genshi bakudan, and both raw material and equipment was destroyed at the Institute for Physical and Chemical Research. To avoid further bombing, the development was relocated to Konan (now called Hungnam, in North Korea) early in 1945. This region was close to the source of ore, in less danger of attack than mainland Japan, and also a major industrial area in Asia. However, the move delayed the development by critical three months. Konan was captured by the Russian army in August 1945, and belongs currently to North Korea. The atomic bombings of Hiroshima and Nagasaki on August 6 and August 9 led to the Japanese surrender on August 15, 1945.
After the war, the U.S. occupation forces found a total of five cyclotrons, which they judged to be part of the weapons programs. Cyclotrons can be used for electromagnetic uranium enrichment as mass spectrometers, but by themselves would not be useful as production facilities. In the United States, large cyclotrons at the Berkeley Radiation Laboratory were used to develop even more massive Calutron machines at the Oak Ridge facility, which were used for the bulk of the electromagnetic enrichment, but the Japanese cyclotrons would have been much smaller than even the prototype American machines. The Japanese cyclotrons were then dumped into Tokyo harbor by the U.S. Army, though many American scientists tried to intervene, insisting that the cyclotrons by themselves couldn't be used to make atomic weapons.
In many ways, the Japanese program is more similar to the abortive German atomic program than it was to the massive Allied bomb program. It is worth noting that by comparison, the Manhattan Project was the single largest expenditure for the American side on World War II ($1.8 billion in 1945 dollars), involved over 30 different research and production sites, and employed 150,000 employees, including numerous Nobel Laureates. Even with this investment, the USA was only able to produce three atomic devices by August 1945.
Disputed reports about the nuclear program in Konan in 1945
Very little is known about the size of the atomic program in Konan though it is conventionally thought to have been small in comparison with the successful U.S. effort. In 1946, a journalist named David Snell working for the Atlanta Constitution wrote a sensationalist story which indicated that Japan had in fact successfully developed and tested a nuclear weapon in Konan. Snell was a former reporter, soon to become Life Magazine correspondent assigned to the 24th Criminal Investigation Detachment in Korea. He interviewed a Japanese officer who said he had been in charge of counter intelligence at the Konan project before the fall of Japan.
According to the officer, who used a pseudonym in the article because he was afraid of retalliation by occupation forces, the program was able to assemble a complete nuclear weapon in a cave in Konan and detonate it on August 12, 1945 on an unmanned ship nearby. Reportedly, the weapon produced a mushroom shaped cloud with a diameter of about 100 m (the first American bomb, "Trinity", had a mushroom cloud some three times the size of that), and also destroyed several ships in the test area. To the observers 20 mi (32 km) away, the bomb was brighter than the rising sun. The officer then claimed that the Russian Army, which captured Konan in November 1945 after some of the last fighting in the war, dismantled the Japanese project and shipped it and some of its scientists taken prisoner back to the Soviet Union.
Most mainstream historians dispute that the Japanese program got close to developing an atomic bomb but US intelligence took the possibility very seriously and continued to question repatriated Japanese from the Konan area about the project.
A 1985 book by Robert Wilcox reprinted the Snell interview as a basis for investigating the Japanese WWII nuclear efforts. In addition to detailing the known Japanese army and navy efforts, the book cites numerous intelligence reports and interviews which indicated the Japanese might have had an atomic program at Konan. It also gave evidence that the Japanese navy, taking up the atomic project after Nishina’s Riken had been destroyed, increased the Japanese efforts to make a weapon. The book, prefaced by Derek deSolla Price, Avalon professor of the history of science at Yale University, who endorsed it, was both panned and praised. Price wrote:
No longer can we maintain that a Japanese bomb just couldn’t have happened. Obviously it ‘nearly’ did. The only questions are how near and what does it do to our judgment on the one case we have of atomic warfare.
James L. Stokesbury, author of A Short History of World War II, wrote:
I had no idea the Japanese were working as seriously on an atomic bomb...this has to modify our perception of one of the crucial issues of the war.
A review by a Department of Energy employee in the journal Military Affairs degraded it:
Journalist Wilcox' book describes the Japanese wartime atomic energy projects. This is a laudable, in that it illuminates a little-known episode; nevertheless, the work is marred by Wilcox' seeming eagerness to show that Japan created an atomic bomb. Tales of Japanese atomic explosions, one a fictional attack on Los Angeles, the other an unsubstantiated account of a post-Hiroshima test, begin the book. (Wilcox accepts the test story because the author [Snell], "was a distinguished journalist"). The tales, combined with Wilcox' failure to discuss the difficulty of translating scientific theory into a workable bomb, obscure the actual story of the Japanese effort: uncoordinated laboratory-scale projects which took paths least likely to produce a bomb. In the historical journal Isis, two historians of science said only of Wilcox's work that his thesis stood "on the flimsiest and most unconvincing of grounds," and surmised that the hidden agenda of such conspiracy theories was "to furnish a new exculpation for America's dropping of atomic bombs on Hiroshima and Nagasaki".