PC: Operation Olympic in Hokkaido

Hokkaido or Kyushu?

  • Hokkaido

    Votes: 9 31.0%
  • Kyushu

    Votes: 20 69.0%

  • Total voters
    29
The invasion of Kyushu was expected to cause anywhere from 70,000 to 766,000 allied casualties, rising to 1.7-4 million if the Japanese populace fought en mass. It is likely that these figures are too low, cobsidering the allies underestimated Japanese troop strength. It would take an estimated 120 days to break through the 900,000 defenders.

With this in mind, would invading Hokkaido be a better option? The allies would have 2-3 infantry divisions opposing them, compared to 14 divisions, 3 tank brigades, and various other units on Kyushu. The defenders on Hokkaido were also oriented north against a potential Russian invasion, leaving the southern beaches undefended.

If the allies go for Hokkaido, they can attack in spring 1945, giving them time to build up for an invasion of Honshu in the fall of 1945.

So, what do you think? I'm especially curious to see how Hokkaido would compare to Kyushu as a staging point for CORONET.
 
Were it me, I'd go for Hokkaido, and once it was taken, tighten the noose around the islands even more. Then I'd offer Chaing Kai Shek the chance to come along on the invasion. We train and equip his boys, and they get in on it. They could then administer the islands too. This way there is less need for the Russians, and the Japanese have another incentive to surrender, as the possibility of a Chinese occupation will certainly be less than pleasant to them.
 
The Allied logistics chain to Kyushu went through the existing bases at Okinawa and in the Philippines and especially Marianas. An attack against Hokkaido would have to come from the Aleutians, which would require massive investment in infrastructure. The invasion would be a shoestring operation at the end of a tenuous supply line with a higher chance of failure, or at least becoming bogged down, than the Kyushu invasion.
 
Plus the Americans going after Hokkaido might cut off Soviet intervention in Japan since they're more likely to come from the north and Sakhalin. And that would hopefully prevent having a divided Japan in this scenario. It might be interesting if the more spread out destruction of Operation Olympic might lead to an Asian Marshall Plan. Which could lead to the Americans funding the Chinese and lead to a Nationalist victory in China. Just a bunch of speculation on my part.
 
Kyushu wouldn't have been as bad as the allies predicted, on Okinawa the Japanese army lost 75% of its automatic weapons and 50% of its artillery. They were defending a bigger area with a severe heavy weapons shortage. Plus if things got nasty the Americans had 500,000 tons of captured German nerve gas in theatre.
 
The Japanese had decided that Kyushu would be where the invasion would be, and moved lots of troops and resources to the area, had lots of deep/cave emplacements, and lots of suicide weapons (planes, boats, "crouching dragons") in place - for example they had caves with suicide kaiten torpedoes or similar in them with rail segments that could be laid down quickly to launch these and then taken up quickly to avoid detection. The landing beaches were limited and obvious and were heavily defended. Defense in Hokkaido were pretty minimal.

On the other hand going to Hokkaido means no supporting land based air - the closest potential Aleutian bases won't do for fighters for sure. The infrastructure to support an invasion is not there. You need supply dumps to store stuff before it goes on ships as well as supplies for continuing operations. You'll want hospitals to take care of the wounded from the invasion. The weather in that part of the world is crappy at best. Flying is bad quite often, and ocean conditions can both be problematic for amphibious operations and over the beach supply and also aircraft carrier operations.

I don't have data on the capacity of the ALCAN highway in 1945, but realistically speaking a big chunk of the invasion fleet is going to have to be loaded in Seattle/Vancouver or maybe Juneau only a limited percentage can be loaded in the Aleutians. This is a long way to go, true the IJN has limited if any capability to interfere with this but it is a long way to go. While taking Hokkaido will prevent the Soviets from taking the Kuriles (probably) and of course would keep them out of the main Japanese islands, by summer 1945 things have not yet fallen apart between the USA and the USSR where the selection of the invasion site would be decided based on what the Soviets might or might not do.

IMHO Kyushu would have been very bad - casualties for Hokkaido would have been less but it is questionable if the USA could pull it off. Also, as the distance from potential Hokkaido airfields to the potential landing sites for Coronet close enough to provide the air cover desired.
 
Kyushu wouldn't have been as bad as the allies predicted, on Okinawa the Japanese army lost 75% of its automatic weapons and 50% of its artillery. They were defending a bigger area with a severe heavy weapons shortage. Plus if things got nasty the Americans had 500,000 tons of captured German nerve gas in theatre.

"wouldn't have been as bad as predicted"? Are you mental? Even adding 500,000 tons of nerve gas into the mix. It would have been bad, very, very bad. Youk now the Japanese planned to basically give everyone with 2 hands something to fight with? You know the Americans planned to use atomic bombs as tactical weapons? It would have been very, very, very, very, very bad.
 
I made my own thread on this a while back.

https://www.alternatehistory.com/fo...f-the-us-invaded-japan-from-the-north.368830/

TLDR: Although the path from Seattle through Alaska to Hokkaido is a much more direct and shorter route, The seasonal weather, Alaskan winds in particular, make airbases on the Aleutians notoriously difficult. I was told off that it would be a nightmare to maintain good supply lines, that the South Pacific is just much better for operations overall, not counting monsoon season.

Also, it was more strategically sound to cut off Japan from their resource islands by bisecting their zone of control at the Philippines.
 
TLDR: Although the path from Seattle through Alaska to Hokkaido is a much more direct and shorter route, The seasonal weather, Alaskan winds in particular, make airbases on the Aleutians notoriously difficult. I was told off that it would be a nightmare to maintain good supply lines, that the South Pacific is just much better for operations overall, not counting monsoon season.

Could the Americans do a "reverse Aleutians" there instead,though?As in didn't seriously commit their forces there.
 
"wouldn't have been as bad as predicted"? Are you mental? Even adding 500,000 tons of nerve gas into the mix. It would have been bad, very, very bad. Youk now the Japanese planned to basically give everyone with 2 hands something to fight with? You know the Americans planned to use atomic bombs as tactical weapons? It would have been very, very, very, very, very bad.
Not as many causalites on the American side,the Japanese would have been slaughtered, Hannibal's long standing record of 50,000 enemy combatants killed in a single day would have been shattered.Thank God saner heads prevailed in Japan.
 
Not as many causalites on the American side,the Japanese would have been slaughtered, Hannibal's long standing record of 50,000 enemy combatants killed in a single day would have been shattered.Thank God saner heads prevailed in Japan.

did you read the part about the Americans planning to use nuclear bombs as tactical weapons? They were told not to enter a nuked site for 24 hours.... It would have been insane. Next to that the resistance they would have faced was way higher than they had anticipated. The Japanese had more than 10,000 planes ready to perform suicide attacks on transports, midget subs/manned torpedos and suicide boats for the same purpose and the population was led to believe the Americans were coming to kill and rape them all(not untrue) so they were all armed and told to fight, they would face the entire Japanese population of 28 million. Not as many casualties on the American side? Try again, it would have been a miracle if the Americans succeed in the first try. I doubt it.
 
did you read the part about the Americans planning to use nuclear bombs as tactical weapons? They were told not to enter a nuked site for 24 hours.... It would have been insane. Next to that the resistance they would have faced was way higher than they had anticipated. The Japanese had more than 10,000 planes ready to perform suicide attacks on transports, midget subs/manned torpedos and suicide boats for the same purpose and the population was led to believe the Americans were coming to kill and rape them all(not untrue) so they were all armed and told to fight, they would face the entire Japanese population of 28 million. Not as many casualties on the American side? Try again, it would have been a miracle if the Americans succeed in the first try. I doubt it.
The Japanese supply situation was a lot more critical than people realized.The military would have run out of supplies right before the invasion, the civilians before that.Add to that the Japanese were trying to do a beach defense putting all their troops within range of naval gunfire add in the stuff the allies didn't have at Normandy like direct fire 203mm howitzers, the 75mm recoiless rifle and napalm.The Japanese would try but they wouldn't be capable of putting up a fight as fierce as Okinawa Allied casualties would heavy but lighter than predicted, 100,000 about half of what was predicted, the shortage of automatic weapons would be the biggest factor.
 
From The Final Months of the War With Japan: Signals Intelligence, U.S. Invasion Planning, and the A-Bomb Decision by Douglas J. MacEachin, Center for the Study of Intelligence (CIA) - a discussion of Americna war planning in mid-1944:

The debate nonetheless continued through the rest of 1944 and the first few months of 1945. Admiral King, while nominally sticking to the position that the end-game would be an invasion of the Japanese homeland, advocated various operations to be undertaken between the seizure of Okinawa and the invasion of Kyushu--for example, attacks on small islands and coastal areas of Japanese-occupied China between Formosa (Taiwan) and Japan. Some analysts have postulated--plausibly--that these operations were seen by their advocates as a way of creating more time for the bomb-and-blockade campaign to produce the surrender they believed could be obtained without an invasion of the homeland.

Considerable debate also took place on the question of an amphibious assault on the northern Japanese island of Hokkaido. The strategic outline accepted by the Joint Chiefs in July 1944 had specifically named Kyushu as the site for the initial invasion. But some planners--with support from General Arnold--argued for attacking Hokkaido first.

Although these discussions initially focused on Hokkaido as an interim step between Okinawa and Kyushu, the debate evolved into an examination of Hokkaido as an alternative to Kyushu. Nearly all members of the Joint War Plans Committee (see footnote 2), however, strongly supported targeting Kyushu rather than Hokkaido. They also objected strenuously to any diversion of resources toward an interim operation.

Apparently Hokkaido was first considered as an interim step between Okinawa and Kyushu, and then instead as a substitute for Kyushu - ultimately, envisioned as a 10 division operation targeting southeastern Hokkaido, particularly around the Sapporo plain. The advantages were obvious: It was sure to be much more lightly defended than Kyushu, and more likely therefore to achieve strategic and tactical surprise. The disadvantages have already been noted: It's much farther from Allied bases, the weather was likely to be worse in the time period in question (and weather would affect not only naval operations, but also the construction of new airfields, and other infrastructure for supporting CORONET in March 1946), and an assault could not be supported by land-based air. Okinawa was, after all, largely targeted precisely because it was close enough to provide land-based air cover for an assault on southern Kyushu. For the Joint Committee, that was enough to shelve it and focus instead on Kyushu.

C-Span had a symposium discussing this as a kind of alternative history exercise, BTW, which may be of interest: "The Hokkaido Myth: U.S., Soviet, and Japanese Plans for Invasion.” It's about an hour long. Worth watching if you have the time.

If there's a logic behind doing it anyway, it would have to be based on the premise of a true awareness of a) how heavily defended southern Kyushu (and the precise landing zones) would actually be, and b) how very difficult it would be for Japan to shift assets (especially air) back up north to meet a Hokkaido invasion, given the lack of fuel and the collapse of Japanese transportation infrastructure, especially the inter-island ferries, under American mining, submarine and air attack. Only at that point would the advantages and disadvantages of Hokkaido be in a position to be reassessed in a light favorable enough to give the operation a fighting chance for approval.

The logic at that point might be that the light opposition would more than offset the inability to support the invasion with any land-based air (and the need to ferry any such AAF assets to airfields secured in Hokkaido by sea).

Yet there's a risk here: If we can interject in to US war planners (some sudden intelligence coup, for example) the full awareness of Japanese defense capabilities in Kyushu, it's arguably more likely to turn U.S. planners against any invasion at all, in favor of the bomb-and-blockade strategy that was favored by Nimitz and King by the summer of 1945 - favored, it should be noted, precisely because their intelligence was uncovering just how intense the Japanese buildup on southern Kyushu was becoming.
 
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