# Did Japan have an Atomic Bomb? **URL:** \ **Category:** Factual Questions\ **Created:** [February 14, 2014, 6:42pm UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354 "2014-02-14T18:42:45Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [February 14, 2014, 10:24pm UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/21 "2014-02-14T22:24:47Z")
> [@The\_Hamster\_King](#): > > Utter nonsense. Concur (although I got whooshed pretty good above…) Richard Rhodes says postwar analysis of the Japanese bomb project shows it never got past some laboratory experiments. As for whether or not an effort the size of the Manhattan District was needed… as pointed out, yes, a many-many-faceted effort was needed to solve the various problems and then come up with enough refined material for at least a few bombs. Now that any bright high-school physics student knows the gist of how to build a U-235 bomb (and the principles if not the extremely precise engineering needed for a Pu bomb), it’s easy to say this all could have somehow been done on some smaller scale - a scale that could have somehow been hidden in wartime Germany or Japan. Note that there has been no massive improvement on the techniques needed to refine uranium, and that the current Iranian efforts are not much smaller than Hanford’s “Queen Mary” refinement factory. Postulating that the Japanese could have solved all the physics and engineering hurdles and then whopped up some nuke fuel in an old sake plant is just bushwah. Unfortunately, it’s the kind of bushwah the “History” Channel has come to peddle nonstop. Zombie threads? I predict we’ll be having this stupid argument for years, every time HC or its successors run their mockumentary and sway another passel of guppies. ---
**Author:** ![The\_Hamster\_King](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)\ **Post date:** [February 14, 2014, 10:30pm UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/22 "2014-02-14T22:30:49Z")
> [@carnivorousplant](#): > > Was something as massive as the Manhattan project required to build nuclear weapons? Yes. A big part of making a nuclear weapon is producing concentrated amounts of the right isotopes of either uranium or plutonium. Since different isotopes are chemically identical this is a very difficult and labor-intensive process. So the research done at Los Alamos was only part of the American bomb program. There was also a massive manufacturing facility at Oak Ridge, Tennessee. Even if the Japanese had known how to build a bomb, it’s unclear whether they could have built the infrastructure to refine the raw materials. In any case, we know that they didn’t. ---
**Author:** ![EdwardLost](https://avatars.discourse-cdn.com/v4/letter/e/bbe5ce/32.png) [@EdwardLost](https://boards.straightdope.com/u/EdwardLost)\ **Post date:** [February 14, 2014, 11:08pm UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/23 "2014-02-14T23:08:13Z")
> [@Amateur\_Barbarian](#): > > Now that any bright high-school physics student knows the gist of how to build a U-235 bomb (and the principles if not the extremely precise engineering needed for a Pu bomb), it’s easy to say this all could have somehow been done on some smaller scale - a scale that could have somehow been hidden in wartime Germany or Japan. I suspect that most of the top physicists in the world already knew the gist of how to build a U-bomb before the Manhattan Project started. Even if Japan had chronoported back a bright, 21st century high-school student, she wouldn’t have been able to help them much. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [February 14, 2014, 11:11pm UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/24 "2014-02-14T23:11:41Z")
Thanks, Hamsterking. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [February 14, 2014, 11:24pm UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/25 "2014-02-14T23:24:32Z")
General Groves was presented with six different methods to produce the Atom Bomb. He was tasked with selecting the one that would be productive first. Instead, he gave the go ahead to _all six_. That’s why the Manhattan Project was so huge and costly. Hitler needed the war over very soon, so the German program was underfunded. Their scientists wouldn’t have been able to get a working bomb in time. The Imperial Japanese detonating a bomb … c’mon … wherever they did would still be dangerously radioactive. I just can’t imagine a hundred square miles of Korea fenced off without anyone noticing. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [February 14, 2014, 11:33pm UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/26 "2014-02-14T23:33:17Z")
> [@watchwolf49](#): > > The Imperial Japanese detonating a bomb … c’mon … wherever they did would still be dangerously radioactive. I just can’t imagine a hundred square miles of Korea fenced off without anyone noticing. Maybe that is why the North Koreans are bat shit crazy. 🙂 Googling indicates that the Germans were sharing Heisenberg’s efforts with the Japanese. Supposedly they sent them ME-262 blueprints. ---
**Author:** ![The\_Hamster\_King](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)\ **Post date:** [February 14, 2014, 11:42pm UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/27 "2014-02-14T23:42:03Z")
> [@Washoe](#): > > So how close were the Germans? When I first saw _The City on the Edge of Forever_, I asked my eighth-grade history teacher if they really were just a couple of months behind us. He didn’t know, and I’ve since asked lots of other people, including college history professors, and have only gotten vague, noncommittal answers. If they had developed one, is there any way they could have delivered it to any point on the Eastern Seaboard? If not, what if they had instead deployed one over London, and effectively said “we’re not giving up just yet, bitches.” Would we have had the capability to ramp up production and built enough additional units to just blast them straight out of the picture? The Germans were a little further along in basic research than the Japanese, but not much. And, again, they never started building the industrial infrastructure that would have been required to actually make a bomb. The thing to remember is that at the time the United States was the only country with enough excess industrial capacity to gamble resources on something like the atom bomb. All the other major combatants – Germany, Japan, Russian, the UK – were straining just to keep their heads above water. Diverting resources to bomb research and production would have meant fewer bombers, fewer fighters, and fewer tanks at a time when every single bomber, fighter and tank counted. Who cares if you’ll have a superweapon in three years if the war is lost six months from now? ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [February 15, 2014, 12:08am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/28 "2014-02-15T00:08:20Z")
Although the Germans were getting heavy water from Norway, Heisenberg was using wax as a moderator in his experiments, and it all fit into a truck. As I said, he was quite surprised when told in custody that the Americans had built several. I would say the Germans were very far away from building a weapon. ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [February 15, 2014, 12:11am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/29 "2014-02-15T00:11:28Z")
> [@EdwardLost](#): > > I suspect that most of the top physicists in the world already knew the gist of how to build a U-bomb before the Manhattan Project started. I highly doubt it. There were several hurdles between the notion of useful/explosive power from an atomic source and actually getting there. Not all of them were understood correctly until other experiments had pointed things in the right direction. While the understanding of how atomic weapons work is now widespread, it was NOT prior to the work of the 1940s. In fact, it has been postulated that the atom bomb was invented/developed only once, and all other iterations are copies of that design. Where the critical specifics weren’t passed along directly (by spies, to the Soviets, or by us, to England) it took only modest effort to fill in the details. After all, once you know that something can be done, and is accomplished by some very narrow set of conditions, things like the exact size of critical mass, shielding etc. can be worked out. Reverse engineering is always a lot easier than getting there in a wilderness. ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [February 15, 2014, 12:14am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/30 "2014-02-15T00:14:27Z")
Good place to add my favorite comment from Luis Alvarez, which pops into my mind every time there’s a news story about the possibility of \*\*_DUN-DUN-DUNNNNNN!_ Plutonium! \*\*in the hands of terrorists or the like: “Detonating U-235 is a matter of dropping one chunk of it onto another. Detonating plutonium is one of the most difficult technical processes I know.” ---
**Author:** ![Mr.Kobayashi](https://avatars.discourse-cdn.com/v4/letter/m/4af34b/32.png) [@Mr.Kobayashi](https://boards.straightdope.com/u/Mr.Kobayashi)\ **Post date:** [February 15, 2014, 12:26am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/31 "2014-02-15T00:26:29Z")
One wonders what the Japanese would even do with an a-bomb if they developed it. They lacked any equivalent of the B-29 or any airfields from which to attack the US directly. Given how much they liked bombing Chungking they might just have driven a suicide truck in there and detonated. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [February 15, 2014, 12:45am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/32 "2014-02-15T00:45:48Z")
> [@EdwardLost](#): > > I suspect that most of the top physicists in the world already knew the gist of how to build a U-bomb before the Manhattan Project started. Even if Japan had chronoported back a bright, 21st century high-school student, she wouldn’t have been able to help them much. The atomic bomb was as much an engineering project as a physics project. More, really. Nobody in the world had any idea of how to build a working bomb before the war. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [February 15, 2014, 12:51am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/33 "2014-02-15T00:51:50Z")
> [@Mr.Kobayashi](#): > > One wonders what the Japanese would even do with an a-bomb if they developed it. They lacked any equivalent of the B-29 or any airfields from which to attack the US directly. Given how much they liked bombing Chungking they might just have driven a suicide truck in there and detonated. Put one in a kamikaze and fly over the American fleet. ---
**Author:** ![Chimera](https://avatars.discourse-cdn.com/v4/letter/c/8e8cbc/32.png) [@Chimera](https://boards.straightdope.com/u/Chimera)\ **Post date:** [February 15, 2014, 12:53am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/34 "2014-02-15T00:53:52Z")
Odds are they would have saved it to try to stop a US invasion, considering any losses amongst their own people to be kamikaze heroes. ---
**Author:** ![EdwardLost](https://avatars.discourse-cdn.com/v4/letter/e/bbe5ce/32.png) [@EdwardLost](https://boards.straightdope.com/u/EdwardLost)\ **Post date:** [February 15, 2014, 12:57am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/35 "2014-02-15T00:57:50Z")
> [@Amateur\_Barbarian](#): > > I highly doubt it. There were several hurdles between the notion of useful/explosive power from an atomic source and actually getting there. Not all of them were understood correctly until other experiments had pointed things in the right direction. > > While the understanding of how atomic weapons work is now widespread, it was NOT prior to the work of the 1940s. This point is probably not worth belaboring, but all I was trying to say is that the information gained during the Manhattan Project, all the details that led to an actual, working bomb, are STILL not common knowledge. I myself know that you have to extract U-235 (a few kilograms), form it into sub-critical masses, and force them together using explosive charges. If I were to phone up a physicist in 1939 and told him that he would say, “Yes, yes, we’ve all guessed that much – but how pure does the U-235 needs to be? How do we do build the extractors? What are the critical masses? How should we shape them? How do we place the charges? How should we detonate them?” I can’t answer any of these and I would be no help at all. Of course there are many people today who could answer those questions, but I doubt many of them are still in high school. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [February 15, 2014, 12:59am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/36 "2014-02-15T00:59:51Z")
> [@Melchior](#): > > Yes, but there are such things as ‘dirty bombs’. Dirty bombs are not nuclear weapons. They are terror weapons only, and nearly useless in a total war campaign like WW2. They would have as much an effect as Japan’s efforts to bomb the US via balloon or submarine. ---
**Author:** ![Mr.Kobayashi](https://avatars.discourse-cdn.com/v4/letter/m/4af34b/32.png) [@Mr.Kobayashi](https://boards.straightdope.com/u/Mr.Kobayashi)\ **Post date:** [February 15, 2014, 1:12am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/37 "2014-02-15T01:12:39Z")
> [@carnivorousplant](#): > > Put one in a kamikaze and fly over the American fleet. Even the four-engined _Enola Gay_ B-29 had to be specially modified to hold _Little Boy_. The Japanese only had twin-engine bombers available. Not to mention, any heavy bomber approaching a US carrier group would be unceremoniously ripped to pieces in short order - Kamikazes were far faster fighters or dive bombers. Maybe they would bury one on some beach in southern Kyushu waiting for the invasion that never came. ---
**Author:** ![cckerberos](https://avatars.discourse-cdn.com/v4/letter/c/f0a364/32.png) [@cckerberos](https://boards.straightdope.com/u/cckerberos)\ **Post date:** [February 15, 2014, 1:14am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/38 "2014-02-15T01:14:13Z")
Japan had two atomic bomb research projects during WWII: The Army’s NI Project which was launched in October 1942. It never had more than 15 personnel, most of whom were young, recent graduates, and was destroyed by US bombing in April 1945. At its height, it may have produced some uranium hexaflouride (used in uranium enrichment). Meanwhile, the Navy had the F Project, which began in May 1943. It had 19 people in theory. The key activity of this project was designing an ultracentrifuge for separating U-235. They completed the plans in July 1945. To quote John Dower: “it seems indisputable that the scale of Japan’s wartime work on the uranium bomb was so small as to be virtually meaningless.” ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [February 15, 2014, 1:18am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/39 "2014-02-15T01:18:56Z")
> [@EdwardLost](#): > > “Yes, yes, we’ve all guessed that much – but how pure does the U-235 needs to be? How do we do build the extractors? What are the critical masses? How should we shape them? How do we place the charges? How should we detonate them?” I can’t answer any of these and I would be no help at all. Of course there are many people today who could answer those questions, but I doubt many of them are still in high school. A guy nearly did it with a screwdriver. Tickling the dragon’s tail. Slammed his hand between the two pieces of U-235 to keep them apart, and died of radiation poisoning. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [February 15, 2014, 1:32am UTC](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354/40 "2014-02-15T01:32:17Z")
> [@Chronos](#): > > They had two, for certain values of “had”. Though they didn’t keep either very long, though. i don’t think they ever had possession of them at least while they were operable. [Previous page](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354.md?page=1) [Next page](https://boards.straightdope.com/t/did-japan-have-an-atomic-bomb/681354.md?page=3)