Could Operation Downfall have succeeded?

Operation Downfall was the name for the planned invasion of the Japanese home islands during WW2. In OTL it was never implemented as Japan was forced into surrender by the atomic bombs dropped on Hiroshima and Nagasaki.

A large amount of information on Operation Downfall can be found here: http://en.wikipedia.org/wiki/Operation_Downfall

My questions are simple. Do you think that this plan could have succeeded? And if successful to what degree? How might the Cold War be altered as a consequence?

This scenario possibly requires the POD of an unsuccessful or delayed Manhattan Project to eliminate the nuclear option used in OTL.
 
Short answer is yes, Olympic/Coronet landings would have succeeded, but very high price in primarily US casualties (basically very few Commonwealth land forces involved, just sea/air). Way way way more Japanese deaths both from military action & starvation, and however much infrastructure and industry existed in Japan on 8/15/1945 after Downfall most of that would have been gone, Japan back to the 16th century economically.

Soviets would have invaded Hokkaido, and you have a Japan with division like Germany - Red Japan consisting of Hokkaido & Kuriles, White Japan everything else, and Tokyo divided like Berlin, although here the USSR is the isolated one. With the Russians in Hokkaido, and the war being longer, probably more support by the US for Chiang, perhaps even significant US forces there and "Red" China either small chunk or non-existent. All of Korea communist.

With more infratructure trashed by the invasions, and Hokkaido stripped by the Sovs, no Korean War to help stimulate Japanese economy, Japanese recovery takes longer & the "super" Japan of the late 20th Century never occurs. With the USSR having Hokkaido as a spot for a naval base with unrestricted access to blue water, something no other Sov naval base has, you will see more of a naval cold war in the Pacific. The non-communist China comprising the bulk of the mainland and Taiwan becomes the economic giant Japan became OTL. Without the Maoist foolishness of the great leap forward, red guards etc you have less starvation, more innovation. Although China TTL does not have same GDP/person that Taiwan does OTL, it is way better than China OTL.

While the details will change due to the huge flock of butterflies released, the internal contradictions and failingds of the Communist system are still there and the USSR implodes in same way or another, somewhere between 1985-2005.
 

CalBear

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Of course.

The only real question was always the losses that would be incurred on both sides.

BTW: It is quite possible that the U.S. would have abandoned Olympic and gone straight for Honshu based on the increasing volume of intel on the IJA/N preparations on Southen Kyushu.
 
I understand the US was thinking about bombarding Japan with poison gas as a prelude to invasion, before the atomic bombs became available.
 
I understand the US was thinking about bombarding Japan with poison gas as a prelude to invasion, before the atomic bombs became available.


Jacobus,

Not exactly. There had been very tentative plans to use gas at Iwo Jima until FDR, aming others, vetoed the idea.

The US, like every other combatant, produced, stockpiled, and staged war gasses near the fighting fronts throughout WW2. All the powers involved had a rough and ready "No First Use" policy in place. No one was going to be the first to use gas, but if someone else used it everyone wanted to be able to respond in kind quickly. IIRC, a German air raid on a southern Italian port inadvertently detonated WAllie chemical munitions aboard a ship resulting in civilian casualties ashore.

As far as the invasion of the Home Islands, the US wasn't planning on using gas but would have gas on hand. Japan, however, was planning on using gas immediately and that would have triggered US gas use in return.

Back to the OP's original question now; this topic is one of the board's perennial discussions. If you use the "Search" function you'll turn up any number of threads that discuss Downfall in all its permutations. One such thread was active less than a month ago.


Bill
 

CalBear

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I understand the US was thinking about bombarding Japan with poison gas as a prelude to invasion, before the atomic bombs became available.


It had been considered, as far back as Pelelui, but against beach defenses, not in any urban or suburban setting.

Use of gas was rejected for the same reason it generally has been for years when there were two major powers involved. Retaliation is too damned easy, and the chemicals cause you almost as much trouble as the enemy.

Gas isn't really all that useful, especially in an urban setting. The B-sans were burning down a Japaese city three-four days a week. They were killing more enemy than any gas attack AND they were burning down infrastructure. That last bit is the REALLY important part; the bombings destroyed Japan's war making capacities, they were against military targets.

Whether the primary goal was to destroy or kill, isn't really critical, that it DID both was. Doing both is war, simply killing civilians with the sole goal of killing civilians, treads way too close to war crimes. There can be, and has been on the board, a great debate on where the line lies, there is a line. The U.S. tried really hard to stay on the right side of that line, and, mostly, succeeded..
 
What the US and Japan had in WW2 were basically the WWI gases, they did not have nerve gas (the Germans thought the Allies did which was one of the reasons they did not use it). Massive use of mustard/lewisite/phosgene etc by the US would not have been effective, and would cause more problems for our forces than it would be and the use by the Japanese would not really do them much good. (insert lots of technical data on concentrations needed, available protection against these agents, expected terrain & climate etc). In mobile warfare (as opposed to trench warfare) persistent gas against supply depot, transportation nodes etc is the best use. In an invasion of Japan, any troop concentrations, depots etc that were found could be more effectively "serviced" by Allied airpower & conventional munitions.

That being said, if gas was used by the Japanese the US would have found some way to retaliate without gassing a city, and in such a way as to not interfere with our ops.
 

Bearcat

Banned
Of course.

The only real question was always the losses that would be incurred on both sides.

BTW: It is quite possible that the U.S. would have abandoned Olympic and gone straight for Honshu based on the increasing volume of intel on the IJA/N preparations on Southen Kyushu.

I suspect its even more likely that the invasion would have been postponed and rescheduled because of intel and the typhoon in September and general reconsideration of strategy. Once it gets pushed back, it might just continue to slip as the US decides to let the blockade starve out the Japanese. The eventual outcome is fewer US casualties but a hell of a lot more Japanese ones.
 
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