Operation Olympic/Coronet - Operation Downfall

All,

Apparantly, Marshall did not believe that Japan would capitulate after the 2 nuclear bombs:

Wiki:

"On Marshall's orders, Major General John E. Hull looked into the tactical use of nuclear weapons for the invasion of the Japanese home islands (even after the dropping of two strategic atomic bombs on Japan, Marshall did not think that the Japanese would capitulate immediately). Colonel Lyle E. Seeman reported that at least seven bombs would be available by X-Day, which could be dropped on defending forces".

Tactical nukes in 1945/6? things moved fast, after all.

What would have happened if another 7-15 bombs (15 being another estimate)had been dropped?

Now, the planned invasion was supposed to be a total US show. King was not even intrested in having RN involved at all, if he could avoid it.

More wiki:

"MacArthur blocked proposals to include an Indian Army division, because of differences in language, organization, composition, equipment, training, and doctrine.[16] He also recommended that the (non-US) corps should be organized along the lines of a US corps, should use only US equipment and logistics, and should train in the US for six months before deployment; these suggestions were accepted"
(Italics are mine).

That is a bit heavy on supposedly allied troops, I should think?

Now, the bigger question is:

Would this massive operation have been along the llines of pacific war invasions of islands or would it have been a more Overlord type operation?

By that I mean: more planning, more involvement of navy/army cooperation, especially if britain got involved?

There is a subtle difference between tarawa and Tokyo Plain?

What now if Churchill/Rosevelt/Truman had agreed that since US had the supreme commander for Overlord, Britain could have the supreme commander for Downfall? Was it even likely (I don't think so, though) and who would it have been?

Brooke? Montgomery? Slim? ??? (maybe they would have hired Manstein on a consultancy contract?)

Another question: How tired of war was the general japanese population at that time? Would it have made a big difference if Downfall was put off until 1948 (as the very early plans had looked at)?

Comments?

ivan
 
The Forces would have been Majority US. I assume to an extent the UK and Commonwealth forces would have continued reclaiming their own territory.

MacArthur had already sidelined the Australian forces as soon as he had sufficient US forces in theatre as it was.

I really don't like that man.......
 
I always considered the Invasion of Japan one of the greatest near-misses in military history. If US predictions had been met, millions dead in months, a nation pretty much wiped off the map to an extent 1945 Germany looks like a nice holiday destination. I think it would have a grave effect on Americans' view of warfare and their place in the world. Losses far beyond anything the United States has ever even come close to. Would it lead to a national trauma? Stronger support for isolation post-war?
 
The invasion of Japan would be the largest military operation the USA ever mounted. Most arguments that Japanese soldiers would not fight to defend Japan rely on the kind of argument that should have seen European WWII end sometime in 1944 when the WAllies and EAllies were in the midst of their big breakouts, instead of the Germans fighting until their country was a mess of rubble and dead bodies fought over by advancing armies. The Japanese knew when and where the US Army was going to come at them, though they were so badly outnumbered and outgunned that the casualties the USA would have sustained would have been primarily from the huge numbers of suicide weapons and the occasional instances of isolated US forces surrounded by stronger Japanese armies.

Most "fighting" would have included instances of untrained Japanese levies forced to charge into the sheer weight of US firepower and being cut down in windrows. The Soviets would be expanding the size of their mainland Empire, fully revenging 1904-5 and the USA would also in all probability finally have a post-ACW event that bypassed the ACW in casualties, as Downfall would bypass the bloodiest Civil War battles in the KIA list on the whole.
 
Jape: Yes, there is another thing there. Post-war trauma? Well, if GI's had to kill millions upon millions of Japanese civilians, I think it would have had a severe impact on the GI's.

Also, the relations between Japan and any other country would have been vastly different if several millions had been killed, and another 7-15 nuclear bombs having been used.

Snake: Would US (at that point in time) have been able to plan and execute it? Overlord showed some very pedestrain US thoughts and doctrines.

Invading Japan proper could not have been compared to anything else but Overlord (yes?).

It is like Sea Lion compared to a river crossing. Not really so.

Ivan
 
Snake: Would US (at that point in time) have been able to plan and execute it? Overlord showed some very pedestrain US thoughts and doctrines.

Invading Japan proper could not have been compared to anything else but Overlord (yes?).

It is like Sea Lion compared to a river crossing. Not really so.

Ivan

Yes, the USA certainly could have done so. It had far too overwhelming an advantage against Japan for them to have a prayer of halting the landing. The problem the USA had is Japan's geography meant the Japanese knew where the USA would land on both islands, meaning the USA has to face a protracted attrition fight ala the Philippines Campaign. Like at Kursk this problem was unavoidable for the USA just as much as it was for the Germans, there are only so many places to attack and invade Japan in this fashion.

Now, as to how the USA reacts to a battle that for the first time since the 1860s would overmatch the ACW in lethality, good question. The ACW was a major trauma for the USA, a WWII that bloody might well make the Cold War much darker and more sordid. Because *both* the USA and USSR had experiences in WWII that brought home the bloody horrific nightmare that is a serious modern war.
 
... or could it have changed the cold war into something else? If both US and USSR had a casualty list into the millions?

What if the early plans for Downfall had come through: delaying the whole thing until 1948? Would US have got tired of the war and settled? what about Britain?

Ivan
 
... or could it have changed the cold war into something else? If both US and USSR had a casualty list into the millions?

What if the early plans for Downfall had come through: delaying the whole thing until 1948? Would US have got tired of the war and settled? what about Britain?

Ivan

No, as the USA and UK and France don't want the USSR to take over all of Europe, and certainly will get paranoid at the likely consequences for Asia here. If the USA waits until 1948 to launch it, Japan surrenders from mass starvation and mass bombing as per OTL.
 
The idea of waiting until 1947/8 was apparantly considered:

I found a reference in this book;

Before The Bomb: How America Approached the End of the Pacific War By John David Chappell

It sort of says that waiting until 1948 would create the impression that "Japan had won", insofar they considered that US would get tired of it all.

If it were "only" bombing, how much would Japan have been able to take? Would additional nucler bombs have been used?

Would the US moral standing have been sunk by turnign Japan into a nuclear wasteland, with (guess) say, 2 million instant deaths (15 bombs * 140,000 killed (+/- Hiroshima)?
 
The US might be more willing to take a nuclear approach than put boots on the ground, if there is a Korean analogue (not necessarily in Korea, that is likely all under the Kims:eek:) the USA might just nuke the offender rather than risk more American deaths
 
There's no question that the U.S. had the ability to mount Olympic and Coronet as planned, even with just U.S. units. The shipping was there, the naval and air support was there, and most of the troops were already in theater, at least for Olympic (renamed Majestic at the end).

The difficulty, as Snake notes, is that geography pretty much dictated where we would have to invade. Southern Kyushu was the only place where land-based U.S. airpower could reach; that was a major reason why we took Okinawa in the first place. The Japanese figured that out quite quickly, and that's why they put most of their troop buildup right there. Moreover, there are only so many suitable landing beaches, given Kyushu's rugged terrain. It would have been hard for Truman to resist authorizing using nuclear weapons in those areas. (And it would, at any rate, have been a more moral use of the bombs than dropping them on cities.)

But as Richard Frank notes in Downfall, it's far from clear that an invasion would have happened, at least as planned. Growing evidence of the Japanese buildup on Kyushu had caused Nimitz, by early August, to withdraw his support for Olympic/Majestic. Had Japan not surrendered, there would have been a hell of a food fight between Army and Navy over the whole invasion question, and I tend to think the whole thing would, at the least, have been reconsidered and reformulated in some major fashion. If not cancelled altogether in favor a bombing/starvation strategy. That's not to say that we couldn't have made the landings successfully, or even attained the campaign objectives - just that it would have been much bloodier than MacArthur's staff (which was low-balling everything) was projecting.

The other item to note is that U.S. success in destroying the rice ferries from Korea and inter-island was on the verge of creating a grave shortfall in food availability to much of the Japanese population. Famine was a very real possibility by year's end. Indeed, the U.S. had to bring in a great deal of food not long after the occupation commenced to avert just that.

Fortunately, we lucked out. Japan surrendered. The alternatives would have resulted in a much bleaker post-war world.
 
Yes, I have also read about the mining of the inland waterways as the most serious threat to Japan.

I was not aware that the starvation option was considered again. For how long could it have gone on? another 1-2 years?

Ivan
 
Yes, I have also read about the mining of the inland waterways as the most serious threat to Japan.

I was not aware that the starvation option was considered again. For how long could it have gone on? another 1-2 years?

Ivan

There was a figure that IIRC CalBear quoted on a previous thread that if the blockade had lasted until December 1946 Japan's population would have fallen to the level of 1700 :eek: The suffering and the collapse of Japanese society would have been totally horrific and today people would have been accusing Truman of being a mass murderer.

As horrible a thing as this sounds in many ways the A Bomb was the best option.
 
Storm: No doubt about that.

However, the bomb could have been delayed for many good reasons. Then what?

Or, no japanese surrender after the first 2? then what? this is what Marshall believed, after all.

Ivan
 
IIRC, Soviets planned landing on Hokkaido by late August. Would that push US into invading sooner than planned 1st November?
 
Fortunately, we lucked out. Japan surrendered. The alternatives would have resulted in a much bleaker post-war world.

Primarily because my father, who was training for the invasion with the on Guam, might never have had a chance to breed me. That would have sucked. ;)

More seriously, East Asia would have been a more volatile place in such a scenario, I think. Possible (even probable) Soviet presences in China and Japan would put the USA toe-to-toe with them on more fronts than OTL, with a greater chance of conflict.
 
This is next to impossible to achieve, as Japan intended to surrender after the Soviets invaded with or without nuclear weapons. Their leadership feared communist occupation more than anything else, and believed that with Manchuria in Soviet hands they would lack the trickle of raw materials necessary to keep the war effort on life support.
 
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