"Invading Japan: How does it end?" Topic

I'm reviewing S&T magazine 45(July-Aug. 1974) that featured the game and article "Operation Olympic", the invasion of Kyushu set for Nov. 1945, and also discussing Operation Coronet, the follow-up invasion of Honshu in spring 1946. There have been more recent games on this subject and probably a certain number of books. As a WWII hypothetical, it is one of the more plausible to speculate about, since plans were well established, troops were being assembled, preliminary moves were being made on both sides, and without the atomic bomb and the Japanese surrender the invasion would very likely have taken place. (Assuming the sporadic Tokyo peace overtures made through intermediaries continued to fail; the Allied blockade was not yet effective enough to have "starved them out" and the Soviets could only wage a mainland campaign.)

There is always a lot of "what if" talk about Allied casualties, Japanese casualties, should the Bomb have been used, etc. and so on but much less any examination as to, Could the Japanese actually succeed in repelling an invasion or bogging one down so badly that the war sputters on and on with both sides exhausted but unable to strike a decisive blow? The fierceness of the resistance on Okinawa gave an idea of what level of fighting to expect on land, and to defend the home islands the Japanese had mobilized millions of soldiers and militia and thousands of kamikaze ships and planes. The Allies may have held a complete superiority in material but Britain and America were beginning to reach the end of their army reserve manpower resources by 1945, from what I read. Could the Japanese have inflicted enough casualties to avoid total conquest, bring the Allied campaign to a stalemate, and extract a negotiated peace on that basis (again, assuming there is no atomic bomb)? Or was it always going to be a futile last stand that would have inevitably lead to the complete occupation of Japan and the deaths of most of its population? What can you better-informed scholars say?

Just a thought, possibility of Chinese troops becoming involved in the invasion post-landings – would add to the available manpower…

I think the Allies could have thrown enough forces into Olympic to take Kyushu. But depending on the scale of the bloodbath, they might have paused to re-think Coronet. No way to tell, really.

I think the Japanese might have put up ferocious resistance on Kyushu, like an even bigger version of Okinawa, and probably sputtered out and surrendered due to a lack of resources. My guess is they would have burned out what will and resources they had fighting out against Op Olympic.

But that campaign would have been bad, even alone. Just my guess, though.

The Soviets would have joined in and Japan learns first hand what scorched earth means.

Just read this morning that as a result of the existing submarine offensive, B29 firebombing, and carrier air raids, the Japanese economy would have ground to a complete halt by the Spring of 1946. Invasion might have been unnecessary.

I'll have to second Korvessa's opinion. The Russians would come in and the Japanese would not have been able to hold on. The casualties estimates of 1 million would tripled.

Japanese were looking to negotiate a surrender from late 44 so blockade the islands, don't waste time and lives with an invasion and get them to a table to talk terms.

> Japanese were looking to negotiate a surrender from late 44

On terms totally unacceptable to the US.

Actually not all that far from what they settled for, so maybe worth thinking about saving a few hundred thousand of your servicemen for

A freaking nightmare is what it would have been. As pointed out the first phase, the invasion of Kyushu would have been like a nastier, more brutal and bloody Okinawa but may have been stopped before it started by Typhoon Louise. That Typhoon roared through the invasion area around the same time the US invasion fleet would have been staging for Operation Olympic. That storm sank or crippled 46 ships and drove 222 ships aground on Okinawa -- and that was when US forces were staging to *leave* and not invade. The damage would have definitely delayed the invasion and caused the Japanese to fight even more fervently, seeing it as another "Divine Wind" that aided them against invaders.

If you read the invasion planning you'll see that the Japanese had the main body of their army in the main Islands, primarily Honshu, plus they had mobilized the general citizenry. They had some 12,000 kamikaze planes hidden in caves and bunkers, 5,000 suicide boats and midget subs hidden along the coast line.

Saeth Wiki: "By the time of surrender, the Japanese had 916,828 military personnel either in position or in various stages of deployment on Kyushu alone.[62] The total strength of the Japanese military in the Home Islands amounted to 4,335,500, of whom 2,372,700 were in the Army and 1,962,800 in the Navy.[63] The buildup of Japanese troops on Kyūshū led American war planners, most importantly General George Marshall, to consider drastic changes to Olympic, or replacing it with a different invasion plan."

US war planners expected the Japanese to use chemical weapons and were prepared to use chemical weapons in large quantities, and also prepared for the use of defoliants against Japanese crop lands and to level pretty much every Japanese city or town they needed to in order to win. The US would probably still ended up using atomic bombs as well. It would have been an unimaginably brutal, awful, hellish campaign lasting as long as a decade after the initial several years of active large scale military actions.

So expect very high US/Allied casualties, many millions of Japanese dead, and for the Japanese islands to have been partitioned between a Soviet controlled North and a US controlled South. Fully engaged by a US invasion I would expect that the Soviets would be able to at least much of Hokkaido, maybe all of Hokkaido and possibly some of northern Honshu, leading to a wall across northern Japan -- a "Bamboo Curtain" to coin a phrase.

What then? Dunno. With the Soviets in Japan perhaps the Korean War wouldn't have happened as it did, sparked by a flippant remark by Atcheson…or perhaps it still would have happened anyways as part of a deliberate strategy by the USSR and China to "flank" the US in the region.

Actually not all that far from what they settled for, so maybe worth thinking about saving a few hundred thousand of your servicemen for

The Japanese wanted essentially a cease fire that left their government intact and let them maintain some of the territory they had conquered during their campaigns in China and in WW2, and that they be able to maintain a self defense force. That's like the Allies accepting that Germany surrenders but Hitler gets to stay in charge, they get to keep a bit of say, Poland Czechoslovakia and Austria and the German military gets to be maintained as a self defense force. Acceptable to you??

Well, that wasn't acceptable. Hell, even after the US had dropped two atomic bombs on Japan there were still many in the government and military who wanted to fight one big, bloody decisive battle (tennōzan) that would convince the Americans that they could never conquer Japan. And some of these factions staged a coup attempt against the Emperor to try and prevent the surrender. That's how chaotic things were.

link

I think it would have been a bloodbath with the unprecedented numbers of suicide attacks possible.

No doubt a brutal mess, but I can't imagine any way in which Japan could have repelled an invasion force in any reasonable manner.

Planning for the invasion involved creating a stock of Purple Heart medals.

Those stocks have yet to be depleted.

> Actually not all that far from what they settled for

Not from anything I've seen.

Well I would have not existed in all probability as the NZ forces would have ended up in Japan at some stage. Assuming Dad was not killed, then my mother and he would in all likelihood not have married. They married in Italy in 1946.

Interesting to think about the Anglo-Allies using their transport capacities to bring over Chinese or Soviet troops. I don't think either of these had sufficient naval forces to have done this on their own to any large extent. Taking on the Japanese mainland would not have been like seizing the Kuriles or southern Sakhalin.

I have been rereading "Tennozan: The Battle of Okinawa and the Atomic Bomb" by George Feifer and it's a nightmare of blood and savagery. Only Stalingrad comes close in my mind to this level of hellishness. Trying to imagine an even worse experience on Kyushu and then maybe a worse one still on Honshu is almost beyond what even Heironymous Bosch could conjure up.

What transport capability did the soviets actually have in their far East?

I assume there was some, but I'd be surprised if it was extensive.

Though naval wargamers might get a kick out of a game of the US Navy running interference to shield Soviet troop ships.

I'll tell ya how it end's:

But the end, when it came,
was to be from the sky-
irresistible, unimaginable,
mushroom-shaped.
Sir Laurence Olivier – World At War

Without the Americans moving the Soviet … or Chinese Corps to the four main Japanese islands they had no capability to land sufficient forces and supply them across the Sea of Japan. Doubt if the British had any excess transport capability to lend a hand which was free to move Soviet or Chinese corps.

Politically, the Soviets and Chinese were screened out of the final invasion of the major Japanese islands. American political policy wouldn't allow them any "credit" for winning the war against mainland Japan. The post war occupation specifically prevented any "token Soviet" forces in mainland Japan.

If the Allied ground forces hit a wall, I think they would have started using the strategic air assets in a more "tactical" role. Carpet bomb an area for days, move troops in to hold it. Repeat. I think they would have become better and better at it.

In terms of capacity, the British Pacific Fleet itself was quite powerful – can't find my reference, but I think that in 1945 it was building up to about 600 ships, including half a dozen very useful aircraft carriers with armoured decks. US carrier gets hit by a Kamikaze attack goes back to port for repairs, Brits mostly sweep the remains off the deck and carry on as usual….

But as far as surplus transport to carry Soviet or Chinese troops, no idea though suspect they could carry quite a few and protect them.

Nice quote here:

PDF link

'TF 37 withdrew to RAS on 30
July, a process which was slowed by further typhoons which caused a great deal of
damage to the wooden flight decks of US carriers but elicited the reply "what storm"
from Admiral Rawlings when asked by Admiral Halsey how his ships were faring,
showing how the BPF's confidence had grown.'

I guess you are forgetting the Soviet invasion of the Kurile Islands which involved over a divisions worth of troops. It also made use of the Soviet Pacific Fleet. Instituted when they had to cancel their invasion plans for Hokkaido.

I do know that USMC troops trained Soviets in the Aleutians (Attu I believe)to fight the Japanese right up to the very end of the war.

I have that old S&T game. And have played many times years ago. Even if other forces would have been involved besides the USA. It would have been a real bloodbath. And if the Japanese fought as they planned. As a nation … they may have been severely attrited.

For better or worse, the A-bombs saved a lot of lives on all sides. Though some still don't see it that way. As Ceterman quoted from the a very good history series from the past … The World at War.
1
That being said, I have heard the USSR was planning on invading from the North. They had enough transport to do such. If the sources I had accessed in the past are correct. If this did occur. Some say there could/would have been a situation like we saw in Korea. With a DMZ between North and South Japan. IIRC the US dropping those A-Bombs may have changed the USSR's plans.

If you want to see how well the IJF vs the USSR. Just read about the Russian invasion of Japanese occupied China/Manchuria. It was not pretty. The IJF were using Type 97s vs. T-34s, etc. …

Not to mention all the 2d rate almost primitive weapons systems that the IJFs were using against the USSR's much more high tech equipment. The IJF was still in the '30s … the USSR was at least a decade ahead if not more.

If they had to invade,
casualties-yes,
ability to repel no.

I know Macarthur wanted it to be a US only show, but given the expected casualty rates I suspect he would have been forced to accept a commonwealth army too.

Given the casualty rates of Okinawa and Iwo Jima combined with western attitudes, there would not have been enough Japanese left to breed.

As much as the Soviets wanted to get involved, it would not happen without western assistance. The only naval forces they had were all the lend lease anti-submarine frigates loaned to them by the US in the last months of the war. In no way near enough to carry or support any force.

The Soviet's had very little amphibious operations experience, training or equipment and not a lot of sea lift capacity. The invasion on the Kuriles was a bloody fiasco. They took 10% casualties on a lightly opposed landing in which most of the Japanese defenders had already surrendered. They no doubt would have brute forced it with typically high casualties resulting in successes.

Ever been to southern Japan? There are incredible plains and crazy mountains. There are chokepoints where the Japanese could have set up stalling tactics and created bloodbaths. It would have been Okinawa all over again only on a significantly larger scale. There would have been ridiculous casualties.

Over one million allied soldiers dead or maimed for life. Over 5 million Japanese dead.

On the lighter side, Godzilla would have never been created.

Upon further reflection -- I am assuming that the US would NOT have agreed to lend transport capacity and protection to any non-Anglo-Allies. For one thing, the US and British navies would have been stretched to their utmost limits by two invasions of the Japanese home islands in six months time (esp. with the expected losses)-- they would both have eclipsed the Normandy landings in terms of size and numbers. Point two, politically the Soviets would not have been welcomed in a partition of japan, which, unlike the situation with Germany, had not been previously decided at a conference. The Soviet fleet was not capable of launching such an ambitious operation on its own, surely? (A division in the Kuriles is not the same thing as invading Hokkaido or Honshu.) And unlike the Americans, the Russians had no idea what to expect from the level of resistance the Japanese had shown in the island war. They had a surprisingly easy time of it in Manchuria and I suspect Stalin would have been happier to take the victories on the mainland, establish puppet states in Korea and China, and let the Americans and British bleed in Japan while he consolidated his gains elsewhere. Point three, the American generals who worked most closely with them did not think much of reliability of Chinese troops in China and so I suspect they would have not been in favor of depending on them to beat the Japanese in Japan, and would not have considered the Chinese worth the trouble of moving, supplying, and overseeing. (Even assuming the Chinese Nationalists were interested in taking on Japan when their own civil war was unsettled.)

That leaves a largely American show, with British support (mainly naval and air, perhaps a corps or army with the initial landing forces or reserves, because the UK was facing severe manpower restrictions by 1945). Perhaps token assets from France and Australia.

Assuming, the invasion went forward (and if the coup against the Emperor's surrender order, the war would have continued), the result would have been as already stated over 1M allied casualties. For the Japanese, the result would have been a self inflicted genocide.

Once they ran out of food (early-mid 1946) and had school children, women and infirm civilians launching suicide charges at Allied troops, the end result would have been the death of most of the Japanese population civilian as well as military.

Only the A-bomb use and the Emperor's wisdom to surrender prevented this horrible likelihood. The Emperor's surrender speech tells it all. Without the bomb's use conventional Allied and Soviet invasions would not have led to the surrender.

Instead of trying to foment a guilt trip on the US, the Japanese should be thanking us for the use of the A-bomb that allowed them to surrender and save the bulk of their population.

US carrier gets hit by a Kamikaze attack goes back to port for repairs.
The US had several floating dry docks in the western pacific for just such repairs. My dad's ship towed one section to the admiralty islands in 1944. These dry docks were big enough to float a battleship. They could be positioned closer to where they were needed to repair damage and return a ship to action in short order.

A good reference source on the planning for the invasion of the Japanese home islands can be found in the book "Code-Name Downfall" by Thomas Allen and Norman Polmar.

Another useful background source is "The History of the Joint Chiefs of Staff in World War II – The War Against Japan", by Grace Person Hayes.

B

The Soviet's had very little amphibious operations experience, training or equipment and not a lot of sea lift capacity. The invasion on the Kuriles was a bloody fiasco. They took 10% casualties on a lightly opposed landing in which most of the Japanese defenders had already surrendered. They no doubt would have brute forced it with typically high casualties resulting in successes.

We know, neither the USSR or IJF were not reluctant to taking heavy losses.
As Major Mike mentioned, The Kurile Islands. The IJFs were defeated by the USSR. They even used PT boats to land some troops. The USSR had 15,000 troops vs. IJF 80,000. In the end, 50,000 IJF troops, were captured or surrendered, etc., … With many being KIA'd, etc., … link

Also note the USSR's invasion of Manchuria, in '45. The IJF were clearly out classed, etc., … link

would have been Okinawa all over again only on a significantly larger scale. There would have been ridiculous casualties.

Yes, that was the overriding reason to drop the A-Bombs …

Instead of trying to foment a guilt trip on the US, the Japanese should be thanking us for the use of the A-bomb that allowed them to surrender and save the bulk of their population.

I totally agree, as do many others. As so often in conflicts, lose thousands to save millions, etc., … That is why IMO, no conflict should be started without considering this.

However, in more current times, some, like jihadis don't care about their losses … Somewhat like the early IJFs in WWII. Eventually even many of the Japanese figured out, resistance was futile … Or lose millions …

That leaves a largely American show, with British support (mainly naval and air, perhaps a corps or army with the initial landing forces or reserves, because the UK was facing severe manpower restrictions by 1945). Perhaps token assets from France and Australia.

That has been my understanding as well …

My 2 cents worth. Japan was planning to use bamboo pikes and the subs had stopped all cargo in or out of Japan. Between combat losses and starvation it would have been genocide for the Japanese.I do not know how many allied men would have died but the US soldiers in Europe believed that when they were shipped to fight Japan that they would all die there.

Worth pointing the IJF in Manchuria in 1945 were a shadow of their former selves having ceased to be an elite force.

'On economic grounds, Manchuria was worth defending since it had the bulk of usable industry and raw materials outside Japan and was still under Japanese control in 1945. However, the Japanese forces (Kwantung Army) were far below authorized strength; most of their heavy military equipment and all of their best military units had been transferred to the Pacific front over the previous three years to contend with the advance of American and Allied forces. By 1945, the Kwantung Army contained a large number of raw recruits and conscripts, with generally obsolete, light, or otherwise limited equipment. As a result, it had essentially been reduced to a light infantry counter-insurgency force with limited mobility or ability to fight a conventional land war against a coordinated enemy.'

link

Biological Weapons and a blockade would have been used punctuated with accelerating atomic attacks as new bombs were constructed. That was the plan at least.

Cheers.
Rod Robertson.

Worth pointing the IJF in Manchuria in 1945 were a shadow of their former selves having ceased to be an elite force.

Even at IJFs at their best … I'd think the USSR would still be more than a match. Even in 1940, the IJFs ground units would still IMO, be defeated by the USSR's tech, etc., … Like at Khahklin Gol, in '39. link The IJF forces had motivation and willingness to die, etc., but their tech for ground troops was very "primitive". Compared to the West, as well as the East.

As a result, it had essentially been reduced to a light infantry counter-insurgency force with limited mobility or ability to fight a conventional land war against a coordinated enemy.'

Even with all their best tech, the IJF would be out matched by the USSR. A very "modern" mobile/mechanized force. At that time one of the best on the planet.

So why did the IJF defeat the US, UK, Dutch, etc., '41-'42 ? I'd think that the USSR after Khalkhin Gol already began to show their dominance over the IJF in '39 link And it just got better by '45. Those others like the US, not only were unprepared, but underestimated a racially different foe, etc., …

Planning for the invasion involved creating a stock of Purple Heart medals.

Those stocks have yet to be depleted.

'Nuff said about expected US casualties.

Tactically/operationally, I would suspect that it would be a long, slow slog to clear the resistance from Kyushu, and Honshu would have been even worse. My guess is that it would have taken so long to secure Honshu that the Soviets could have invaded Hokkaido.

Based on civilian casualties at Okinawa, it's likely that half the Japanese population would have been killed before the government surrendered.

The USSR had 15,000 troops vs. IJF 80,000. In the end, 50,000 IJF troops, were captured or surrendered, etc., … With many being KIA'd, etc.

Yet as the link pointed out that happened *after* the formal surrender of Japan, most of the Japanese defenders did not resist and had *already surrendered* -- yet the Soviets got chewed up pretty hard by those few Japanese units that ignored the surrender command.

Now flash over to ALL of those Japanese units fighting at least as hard as they did in Okinawa and the initial Soviet invasion of the Kuriles fails completely. After a nasty campaign for the Kuriles they'd have to invade the much much larger northern Island of Hokkaido.

Good point … I just thought I'd post those links to add more information … But yes, the USSR did lose a number of troops in the Kurile Invasion. I guess my point being in the end … Japan lost and the Russians were on the winning side.

And again, I'd think in the long run, if the IJF did not surrender, the Russians would have been willing to take heavy loses as the US did on Okinawa, Iwo, etc., …

And it appears, that the two A-bombs dropped on Japan may have saved Russian lives as well …

The US would have starved the Japanese. Defoliating crops, destroying all fuel supplies, bombing all roads. People, no matter how fanatic, don't live without food.

what ships/equipment of there own did the russians have to land troop
did they have lst's( mention made above about t34 tanks)

what ships/equipment of there own did the russians have to land troop
did they have lst's( mention made above about t34 tanks)

Under Project Hula, the US transferred under Lend/Lease 30 LCI(L) (landing craft, infantry, large) to the Soviets. None of which were capable of landing any vehicles of any size (and definitely not T34s). In fact, the Kuril landing's mixed results were due, in part, to the lack of any armor or artillery. So, to answer the question, can the Soviets successfully land on Hokkaido? Not even remotely.

The US would have starved the Japanese. Defoliating crops, destroying all fuel supplies, bombing all roads. People, no matter how fanatic, don't live without food.

And 10-20 million civilians would have died as a consequence. Starvation tactics fall hardest on the lowest level of society since the government will do all possible to keep the military fed (and everyone else be damned).

Gas

Gas

Assuming you're referring to gasoline (or, more correctly, POL stocks), the Japanese government had started putting aside large quantities of fuel for the expected invasion as early as 1944. This was one reason why the air defense effort fell-off during mid 1945; they were conserving their fuel stocks for the final defense. So 'gas' would not have pushed the Japanese cabinet to surrender.

No

I meant Mustard, phosgene, Sarin, the whole hell of chemical warfare. Add to it bio warfare, smallpox, bubonic plague, pneumonic plague, etc.

As I said in the other list about the morality of the end of war, if the Japanese government is going to make every citizen a combatant then every citizen is a legitimate target.

Atomic bombs? Fire bombing? Just part of the mix.

That is, IF you believe the Japanese would not surrender.

However I am not so despairing as most of you.

Japanese suicide deaths ancilliary to battle and the rush to self immolation with bamboo spears against machine guns was on small islands, isolated and besieged in a culture heavily militarized by the presence of massive military formations.

Unlike their military commanders I believe that the Japanese people did not share the hyperventilating propaganda to the extent their leaders did and wanted them to. Certainly there would have been some "radicalized" individuals who would have picked up their bamboo spears, but I think that the majority of the people of Japan would have chosen life rather than death. I think that they would have fled to the mountains and especially the women would have chosen life for their children and babies and would not have rushed to die for Nippon. I also think that after the invasion of Kyushu the benign rule of America over the survivors would have mitigated their ardor, and the Emperor himself would have constantly been leading the pack.

I also think you all underestimate American desire to NOT kill Japanese civilians. Many times on islands Americans went through extravagant lengths to try and get the Japanese to stop fighting and surrender. Especially with civilians, even hardened American military leaders were emotionally effected by these deaths and tried to stop the suicides and to try and get the civilians to not take such extreme measures and even wanted to save the obviously now shattered remnants of the Japanese armed forces.

I think you underestimate the lengths to which the Americans would have set their minds to this problem and I am sure that a means would have been found. During these campaigns extensive use was made of those Japanese prisoners who had been treated well to try and convince their former compatriots that they would not be killed or tortured. I think a massive psychological operation would have been mounted to try and do this.

I can even see the Americans parachuting former Japanese soldiers and civilians captured who had seen that the Americans were not the monsters their leaders had painted them into Japan to try and convince, at peril of their own lives, the Japanese to surrender to mercy.

You will all of course call me naïve and idiotic for this, but I believe in basic humanity and human virtues, and I think that most people would rather live than die for the ontological principle.

I believe in the power of kindness and mercy.

Normally I find myself agreeing with you Otto but with the example of what happened with a large indigenous population on Okinawa I am not so optimistic.

Some bleak but true comments. The Japanese should have thought about this before they bombed Pearl Harbor maybe ?