WI: US Invades Hokkiado Northern Japan in 1944?

WI: US Invades Hokkiado Northern Japan in Fall 1944?

JapanPrefHokkaidoMap.png


Reacting to the fall of the Marianas, Imperial Headquarters quickly formulated new plans for a decisive showdown with the enemy. These plans were given the code name "Operation Victory." The plans were numbered one through four, according to the four probable directions in which the enemy might advance: 1) the Philippines, 2) Taiwan and the Ryukyus, 3) the Japanese mainland and 4) Hokkaido.
Hiromichi Yahara

So the United States decides to invade Hokkaido in the fall of 1944. What would kind of force would be needed to secure the Island? Could other operations still occur elsewhere? Impact on the war and Japanese moves? Soviet reaction to the invasion?

In mid-July 1945 shipping, cities and military facilities in Hokkaido were attacked by the United States Navy's Task Force 38. On 14 and 15 July aircraft operating from the task force's aircraft carriers sank and damaged a large number of ships in ports along Hokkaido's southern coastline as well as in northern Honshu. In addition, on 15 July a force of three battleships and two light cruisers bombarded the city of Muroran.
https://en.wikipedia.org/wiki/Hokkaido
 
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Not a chance in hell. The US military would never throw its men into the massive meat grinder that was the Japanese Home Islands.
 
Not a chance in hell. The US military would never throw its men into the massive meat grinder that was the Japanese Home Islands.

Perhaps the US wants to preempt the Soviets or something. I agree its very very unlikely but the Japanese at least thought it was possible.

What do you think the defences would be like? I imagine US air and naval power would limit the amount of reserves that could flow north. Should the US take the Island quickly what would it mean for the war? Japan's core areas within bombing range much earlier then OTL?

It seems like the defences would be weak if Kyushu wasn't even well guarded at this point:
In March 1945, there was only one combat division in Kyūshū. Over the next four months, the Imperial Japanese Army transferred forces from Manchuria, Korea and northern Japan, while raising other forces in place. By August, they had 14 divisions and various smaller formations, including three tank brigades, for a total of 900,000 men.[50] Although the Japanese were able to raise large numbers of new soldiers, equipping them was more difficult. By August, the Japanese Army had the equivalent of 65 divisions in the homeland but only enough equipment for 40 and only enough ammunition for 30.
https://en.wikipedia.org/wiki/Operation_Downfall
 
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I vaguely remember this scenario, or something similar, being proposed in France Fights On, back when it was still one team. The European members promptly ignored it.
 
I think MacArthur would probably have a cow, because he would want any troops that would be in that invasion for the Philippines campaign. Considering by this time he pretty much had total control over how the Pacific theater was handled, he probably would have nixed that invasion and put everything into the Philippines.
 
By what route? The only viable way is through the Aleutians by means of the Kurils, which is additional fighting, is liable to piss off Stalin, and also involves maintaining supply lines in a very difficult sea environment (think Deadliest Catch). Not doable unless the Soviets are in on this much more than they ever were. Also not a good idea in general in 1944--the strategy the US was using was producing enough results, wasn't it?

For a non-Downfall/non-Soviet invasion of Hokkaido, you'd need for some reason to have the US decide to take the northern route instead. After all, its less than 750 miles between Attu and Paramushir. But again, there's the problem with the very difficult weather in those seas, the need for Soviet approval, and the fact the US would need to go south anyway at some point to deal with the problem of the Japanese Navy.
 
The problem with Hokkaido is the logistics. The weather and sea conditions in that part of the world are crappy at best and go down from there. While the distances on a map from the west coast of the USA to Hokkaido (via Alaska/Aleutians) may "look" shorter than trans-Pacific, the environmental realities are worse. Furthermore Hokkaido is out of the range for land based air from any base the USA had (meaning they would need to seize one of the Kuriles first), and in any case as noted weather is so crappy that counting on flying support missions was a no-go. This means, even if you are willing to go with just carrier based air based air, air support for any landing is touchy until you set up bases on Hokkaido.

Lastly, once you get Hokkaido, what have you gained. even assuming the "cost" was no more than Okinawa, you aren't much better off for a subsequent invasion of Honshu, and your build up will be more difficult.
 
a few things....

Hokkaido is very weakly defended in 1944 compared to Leyte or Luzon or Formosa

In 1945, using B29s to lay mines and American carrier strikes to destroy or knock out of action the rail ferries, the island was essentially isolated from the rest of Japan (which had dire effects for food and coal supplies in the rest of Japan)

The invasion of Leyte was outside the range of land based fighter cover for all but brief periods

where ever the Americans land in 1944, they are attacking the Inner Defense Perimeter and landing somewhere vital... the IJN will come to where ever that is. As most of the Japanese battle fleet is in Indonesia (where the oil is), this is a pretty long distance with the requisite curtailment of operational flexibility. Plus of course the route north is pretty obvious, which makes multi prong attacks unlikely.

Taking Hokkaido gives American tactical aircraft the run of all of Honshu several months earlier than in OTL, with the requisite devastating effects on Japan

Disadvantages
the weather.... Hokkaido is northern temperate, which means winter is a real factor. Heavy seas, storms and cloud cover mean that the window is late spring - early fall. Guam didn't fall until August (last major battle of the campaign), which means unless the US Navy can immediately launch a major operation (Peleliu is September, but is only a single division, while Leyte is October) weather issues close down this option until the Spring of 1945

Hokkaido is well within range of Japanese air power, and there is a lot of it in the Home Islands. The decision has already been made by October to use Kamikazes, at least in a small scale. Thus this operation is very high risk for Fall 1944.

While isolating Hokkaido significantly is relatively simple (submarines can lay mines, B29s can help), nevertheless small craft can reinforce Hokkaido with what divisions are available in Japan itself (not many, but there some and Manchuria isn't that far away)

So Hokkaido has to been taken quickly (and its a big place) or it becomes a costly war of attrition.

But really the weather window is the biggest problem and that one can't really be overcome
 
If something like this should happen, I see the Japanese utilizing kamikazes right away. The sheer logistics to get supplies to the landing sites will be a pain.
 
Logistically unfeasible and militarily precarious. The Americans only would have tried something like this when they had the proper air cover and supply bases to support it.
 
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