AHC: Operation Downfall + Soviet invasion of Japan

If Gadget fails could it delay the Manhattan project long enough for Downfall to go forward?

Sorry, just noticed this.

I actually looked at this myself a while back. Sadly, it doesn't look plausible.

The Trinity test was on July 16th, just inside the OP's allowed POD. If it fails, the bomb known as Fat Man in OTL will almost certainly be used for a second test. Having both tests fail when both devices functioned in OTL is pretty ASB to me. At least one more implosion type weapon (I believe more, but can't find reliable sources on the web) was available before the end of July.

USS Indianapolis (CA35) departed San Francisco with Little Boy's core on July 16th. She dropped it off on Tinian on the 26th and was sunk on the 30th. In OTL she stopped at Pearl on the 19th; if the Trinity Gadget had failed she might be held while scientists explain to politicians that Little Boy is just about fool proof and doesn't need to be tested.

I've yet to find an IJN submarine for her to run across while enroute to Tinian after her delay at Pearl, but that's my favored way of disposing of Little Boy. On the plus side, her distress message can get through and most of her crew is saved. :)

The problem is even with the Trinity Gadget destroyed in a failed test, Fat Man used in its place, and Little Boy lost at sea, there's still another implosion device available to be dropped in August. I can't find a non-ASB way to get rid of that one except political fiat; Truman decides he's fed up with all the bad luck and decides that the 3rd implosion device will be used to support the invasion, along with whatever other weapons are available at that time. That isn't at all likely IMO, but if anyone has a better idea I'd really like to hear it!

Edit to change: changed "Trinity" to "Tinian". Oops. :-(
 
Sadly, it doesn't look plausible.


You're correct about that, but you've got the rest all jumbled up.

This is yet another Done To Death(tm) here and one that I and others seemingly have to provide explanations for on at least quarterly basis.

Let's clear up all your confusion, okay?

  • There are two kinds of bombs: uranium gun-slug type and plutonium implosion type.
  • The Trinity Gadget, Fat Man, and the unused Third Device are all plutonium implosion types. Unlike the uranium gun slug type, this type had to be tested due to the bleeding edge explosive geometry and firing circuit needed for the implosion of the plutonium "shell".
  • Little Boy was a uranium gun-slug type. That design was considered such a no-brainer that the Hiroshima drop was it's first "test".
  • USS Indianapolis carried the cores for Little Boy.
  • After Nagasaki, there was another plutonium implosion weapon available for use on Tinian. At the same time, there was enough fissionable material available for other bombs, at least one more uranium gun-slug type and a varying number of plutonium implosions types, in the continental US.
  • As part of of the Olympic portion of Operation Downfall, at least nine atomic weapons were supposed to be available for use by November 1, 1945.
 
You're correct about that, but you've got the rest all jumbled up.

This is yet another Done To Death(tm) here and one that I and others seemingly have to provide explanations for on at least quarterly basis.

Let's clear up all your confusion, okay?

  • There are two kinds of bombs: uranium gun-slug type and plutonium implosion type.
  • The Trinity Gadget, Fat Man, and the unused Third Device are all plutonium implosion types. Unlike the uranium gun slug type, this type had to be tested due to the bleeding edge explosive geometry and firing circuit needed for the implosion of the plutonium "shell".
  • Little Boy was a uranium gun-slug type. That design was considered such a no-brainer that the Hiroshima drop was it's first "test".
  • USS Indianapolis carried the cores for Little Boy.
  • After Nagasaki, there was another plutonium implosion weapon available for use on Tinian. At the same time, there was enough fissionable material available for other bombs, at least one more uranium gun-slug type and a varying number of plutonium implosions types, in the continental US.
  • As part of of the Olympic portion of Operation Downfall, at least nine atomic weapons were supposed to be available for use by November 1, 1945.

Err... what in my post contradicted anything you said here except my uncertainty about the number of additional weapons available?
 

Sir Chaos

Banned
Sure... if the Japanese had fuel. Which they didn't.

For example, Nagato would have to sail to Hokkaido, AFTER remounting her rangefinders, AA guns, and secondary battery and repairing the bomb damage from the July air raid. She was only really ready to be a shore battery by the end of July.

Most of the kamikaze force assembled to resist the anticipated US landings only had fuel for their attack runs; at least a few of the pilots had never flown before and hadn't even had theoretical training in how to land. Even if we magically shift them to northern Honshu, they'd be trying to target small landing craft. Anything they hit will die, but in OTL kamikaze's often missed full-sized surface combatants. Also don't forget the Red Air Force will be providing cover. LOTS and LOTS of quite good aircraft. Yak-3's with veteran pilots will probably do at least as well as Hellcats.

Remember, the Soviets did invade and capture the Kuriles in OTL, and they could stage out of Sakhalin Island (which they'd just finished capturing the south half of). US assistance in those ops was minimal to non-existent.

We´re not necessarily talking about a mid-to-late ´45 invasion. If we assume the plotters in Germany kill Hitler and negotiate a surrender to the Allies, the Soviets could invade Japan a lot earlier - perhaps concurrently with the US invasion of Okinawa, perhaps even concurrently with Iwo Jima - or perhaps in between these two operations.

The IJN is stronger at this point - Yamato still exists, there is one more light cruiser and another couple of destroyers, and probably more fuel as well.

I think it would have been possible, but the Soviets would have needed US naval support.
 
Nothing actually.

I said you were basically correct but you had some of the details jumbled up.

I'm re-reading it again, and I don't see any details jumbled up either.

Since this is TL I'm trying to develop, I would greatly appreciate it if you could point out any errors.

Thank you.
 
I'll chip in my $0.02 and leave to others to point out other threads. :)

Japan in mid-1945 had two hopes:
1. That the USSR would serve as a mediator for a negotiated peace with the US.
2. That the US would invade and incur such high casualties that they would decide the war wasn't worth it and negotiate a peace.

Neither of these hopes was actually realistic, but the Japanese needed to be convinced.

The Soviet invasion convinced them #1 was a non-starter.

The atom bombings hammered home the point that the US didn't need to invade or incur high casualties to annihilate the Japanese as a culture.
Blockade and aerial bombardment would do the trick at minimal cost in lives and an acceptable cost in material.

Augmenting the above was that the allies got across that they were willing to leave the emperor in place. This was quite important IMO because it both
saved 'face' (VERY important to the powers-that-were) and it held out a new hope: Japan wouldn't be partitioned and its leaders sent to war crimes trials - i.e. a better fate than that of Germany. As it turned out this hope was justified: the Japanese got MacArthur, not Nuremberg. Good for them, not so good for justice

None of the three - the invasion, the bombings, or leaving the emperor would have been enough of an by themselves. I think it required all three to secure a surrender.

Some people on this board believe only the Soviet invasion was necessary, and I'm happy to concede that this is a reasonable position backed by serious
evidence. I don't happen to agree with it, but hey... :)
umm... Dude the Japs did not get of Scott free.... Have you heard of the east Asia trials nearly all the major Japanese leadership was executed and only the Imperial family was spared, that part you spewed is BS.... Otherwise I agree with your post.
 
We´re not necessarily talking about a mid-to-late ´45 invasion.

Good point, I had forgotten that. Yes, faced with an active IJN, the Soviets would need US help.

To get an earlier invasion... hmm. What if the IJN actually did lose two carriers in the Pearl Harbor op? IIRC they had wargamed it and considered that possible and acceptable. With fewer fleet carriers available they might not reach for objectives like the eastern Solomons, and the US counter-attack might begin a little further west. Plausible?
 
umm... Dude the Japs did not get of Scott free.... Have you heard of the east Asia trials nearly all the major Japanese leadership was executed and only the Imperial family was spared, that part you spewed is BS.... Otherwise I agree with your post.

Ah... certainly I'm not familiar with that title. I googled "east Asia trials" and got a lot of links about soccer. Do you mean the Tokyo War Crimes Tribunal? They specifically excluded the royal family, and MacArthur granted immunity for all charges of bio-warfare experimentation, including human subject testing. Can you imagine if the Nazis at Nuremberg had been granted immunity for all crimes against Jews?
 
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