I was looking at some old newspapers on newspapers.com - mostly US (my country), but some British and commonwealth. Right around VE Day, seems like reporters talked to everyone who could conceivably have an opinion and found out how long they thought it would take for Japan to be defeated. I saw numbers anywhere from 3 months to 3 years. Obviously, the former was the more accurate.
But do we have internal documents saying how long the military expected it to take? The higher-ranking government officials? Did it vary by country?
The military hoped that it could be done within a year of Germany’s surrender.
3 months was definitely over-optimistic. That number probably came from how quickly Germany folded towards the end of the war. But many allied soldiers often commented that the Germans no longer had their heart in it and were quick to surrender when they realized that defeat was inevitable.
Not so for the Japanese. One thing that they had proven in the Pacific was that they would fight to the bitter end for every tiny scrap of land. The invasion of their homeland was expected to be long and bloody. The U.S. military expected anywhere between 500 thousand and a million U.S. soldiers killed.
In fact, even after the bombing of Hiroshima and Nagasaki, the military was looking into the possible use of tactical nukes since even after the bomb’s destructive capabilities were known, they still didn’t expect the Japanese to surrender.
Personally I think the one-year plan was also overly optimistic. The geography of Japan is such that the Japanese were easily able to predict how we would attack, and were already making preparations for it.
Wikipedia’s article on Operation Downfall is a good place to start:
Yes. Absent nuclear weapons, the complete occupation of the home islands was expected to be completed by around April 1946, after two phases of invasion (one around November 1945, the other around February or March 1946).
The wild card was the effect of the Soviet Union’s invasion of Japanese-held Manchuria, which was due to start in early August 1945 (as it indeed did, the same week as the atomic bombs IRL). It’s quite likely the Soviets would have reached to home islands around the same time as, or a little before, the US did — exactly what actually had happened in Germany — and would have resulted in similar Cold War partitioning.
Another wild card was how the Japanese might react to the Soviet invasion of Manchuria. Would they fight to the bitter end or would they pull their troops out of Manchuria back to defend the home islands? As it turned out, the Soviets attacked with a massive 1.5 million troops across multiple fronts, overwhelming the Japanese before they could enact any strategic response.
The Japanese had removed many troops for the battles in the Philippines and Okinawa, so the Soviets were able to crush them easily.
I had a friend (recently passed) who served in the US Army in WWII. He deployed to a quiet sector of the front in the fall of '44 (you can probably fill in the gaps), so he didn’t have the points to go home. He got a 30 day leave then reported to a camp on the west coast.
He was slated for Operation Olympic until the bomb was dropped. He ended serving in the occupation of Japan for a year or so. At the time, he thought the bomb was the greatest thing–it meant he would live.
My dad as well [well actually he was in from Normandy through being shipped off to the west coast in preparation to heading to Japan. ] He and my grandparents I am very certain were thrilled he wouldn’t end up in the meat grinder that Japan would have been [he got shifted from Armored to Engineers so he would have been involved in making things go boom on a smaller and more sneaky level, or keeping things from going boom depending. ]
While the anecdotes are nice, I’m looking for actual documentation reviewing or communicating expectations from high-level persons. Particularly from around May 1945, not several months earlier, as things can change quickly.
The Soviets and the threat the presented have been mentioned, and indeed were discussed in articles of the time. But I don’t really if we have any sources on how Allied military or civilian governments expected Japan to respond to them - what odds did they give on it ending without invasion of the home islands? I know what the US was willing to do, and the Soviets. But I also know Japan was trying to use the USSR as a middle man to get peace (at terms completely unacceptable to the Allies) and that the US had intercepted those communiques. But did any parties take that to mean Japan might surrender before an invasion of the home islands if enough pressure was kept up?
I know that some US forces expected a much more mindless, slavishly devoted to the Emperor populous than they actually got after the war. Obviously, misviewing that would lead them to think it would take longer. I believe, but am not certain, they also overestimated Japan’s available resources (food and other), so that might have made them project that Japan could hold out longer than it could (even if the bombs hadn’t existed).
I think this is very accurate. Hell, Iwo Jima wasn’t much more than a pile of rocks, and they fought to the death. Some even committed suicide in the caves with grenades rather than surrender.
Getting onto the home islands would have been extremely problematic for the Soviets; they had very little amphibious lift capacity, and what they had they had gotten from US lend-lease in Project Hula to support their operation on Sakhalin and the Kuril Islands. Naval gunfire support for any landing operation would have been near non-existent, as would adequate protection from kamikaze attacks. The invasion of Shumshu in the Kuril Islands was quite brutal despite taking place after Hirohito announced Japan’s intention to surrender on August 15th.
Historians have generally considered it unlikely that an invasion of Hokkaido would have succeeded. Factors include the small number of Soviet transport ships, the small number of Soviet ground forces planned for the invasion, and the availability of Japanese air power including kamikaze planes to contest a Soviet landing. Soviet forces suffered heavy losses in the Battle of Shumshu during the invasion of the Kuril Islands, and historians foresaw similar problems plaguing an invasion of Hokkaido.[1][12]
Historian Dennis Giangreco believes that the Japanese forces would have fiercely fought back against an attack after their country had surrendered, and the small, hastily-assembled Soviet forces would have been unable to hold out against them. Because the Soviets thought the Japanese would not contest a landing after they had already surrendered, they assembled a relatively small force of two divisions, much smaller than the four field armies, totaling about 12 divisions, which Marshal Georgy Zhukov estimated would be necessary for a full-scale conquest.[1]: 155–156 However, after the Japanese fiercely defended Shumshu three days after the surrender, the Soviets were forced to reconsider this assumption.
The division of Germany that was agreed upon at Yalta also made it clear that there was to be no partition of Japan, so an attempt by Stalin to brute force his way into the occupation of any of Japan proper wasn’t going to be looked upon too kindly or result in the US trying to help pull his chestnuts out of the fire in a botched invasion of Hokkaido.
I believe the 1st invasion of the main lands was planed for May 1946.
In one of my books I read where the mayor of Hiroshima was encouraging the citizens to hold on Japan would be victorious.
3 days after the 2nd bomb was dropped Japan had not surrendered yet. But on that 3dr day LaMay was able to obtain one of his goals. He set the goal to have 1000 planes over Tokyo. Before the last plane landed after the bombings Japan has surrendered.
Operation Olympic was to take the southernmost main island Kyushu and was scheduled for November 1945. As it turned out a Typhoon in November 1945 went right through what would have been the staging and landing area that same month.
Operation Coronet was scheduled for March 1946 and was to take the largest Island Honshu.
It took nearly 3 months to take Okinawa, so in the best case scenario, Olympic might be concluding just as Coronet is scheduled to go. So March 1946 seems optimistic.
Also, there was no confusion among the Japanese (unlike D-Day) regarding where both landings would take place. So if you use tiny Okinawa as a model, I don’t see any way that it doesn’t drag into 1947.
Thanks. This is just the invasion plan and timeline with the “assumption” of continued aggression to the last, though. I want the political perspectives of whether or not it was universally agree that that assumption was valid and that was the only way unconditional surrender could be achieved. Military ones, too. I can absolutely believe everyone assumed that, but this document doesn’t say that, because it just takes it as a given for the sake of the plan because this document is only applicable if invasion happens.
There didn’t seem to be much of a consensus among high level people. According to the Wiki article posted earlier, MacArthur’s staff were estimating 23,000 casualties in the first 30 days. General Marshall and Admiral King were estimating 30-40,000 in the same timeframe. Admiral Leahy, basing it on the experience of Okinawa was estimating 250,000+. So there’s three 5 stars who are all over the map regarding casualty estimates.
I know your question was regarding timeframe, not casualties. But timeframe is gonna depend on whether it goes as smooth as MacArthur was envisioning or as bad as Leahy thought. I don’t think you’re gonna find any document from the time with a broadly agreed upon estimate.
The pre-invasion map projection of Allied advances up to D+90 for the landings at Normandy compared to what the actual advances were is an interesting illustration of military planning vs. realities. In the end, Allied projections on where the front line would be at D+90 match up reasonably well with where the front lines actually were on D+90, but up until D+50 the Allied lodgment was still only about halfway to where they were projecting it to be by D+17. The advance was far behind schedule up until the German lines finally broke on D+50, with the remaining distance up to where things were projected to be after 90 days then rapidly being made up.
True. But there were broadly agreed upon projections prior to Normandy even if the specifics regarding the first 90 days ended up being wrong.
There were no agreed upon projections for Downfall, at least not as of August 1945. It could be that in the 3 months between August and November a consensus would have been reached. Or maybe they would have just held their breath and hoped the optimists were right.
America was the main country involved and I haven’t looked at any planning by the British but it’s likely that they would have different conclusions than the US military.
However, it varied wildly by service branch and not only by service branch, but also by the various groups and leaders within the branches.
For example, Hap Arnold was adamant that his air forces could bring Japan to her knees by themselves and didn’t require an invasion. His staff produced high estimates for casualties in case of an actual invasion.
OTOH, the planned invasion of Japan would place MacArthur in the driver’s seat and he was asking for a an unprecedented sixth star so we could outrank everyone else. His staff lowballed casualties to make the invasion more likely to receive the go ahead from Washington.
The Navy was becoming increasingly nervous about the whole thing as well. King and Nimitz were having discussions about their concerns up until the end of the war.
Other Army leaders back in Washington were also starting to worry about the potential number of casualties as well. There were various debates among all of these groups. The number of estimated US casualties was growing as the potential dates of the invasion were starting to come closer.
They didn’t have perfect information about the various units in Japan, and intelligence disagreed with itself. Note that as the potential fight came back to Japan, more communication was done over wires and less over radio signals, so they lost ability to intercept more of the messages.
Not only did people, units and branches have honest disagreements about Japan, they were positioning themselves for postwar funding and importance. Any estimates by various people needed to be looked at for this possible bias.
There are documents online. Most of what I know has come from reading various books and looking online for specific questions over the years. Looking back, I should have better documented what I found so make it easier to find. I presume most of us who are interested may have a similar approach, but YMMV.
After read the Post article posted by @Kent_Clark after I wrote the above, and it matches what I’ve read other places.
MacAurthur really wanted the invasion. There have always been questions about how much military leaders place personal glory above other considerations, and Mac was Mac.
Note that this concerns the June 18th meeting, and the bombs were dropped a month and a half after that. During that time, Army (except Mac’s staff) and Navy estimates continued to grow.
Also note that the estimated number of casualties has become part of the postwar debate over the use of the bomb and the two sides of that debate have honed their skills at cherrypicking numbers.
What do you mean by “universally agreed”? As is bured in my long post above, Arnold believed his airforces could force the surrender by themselves, a view not shared by other branches.
Also note that the reports from factfinding teams in defeated Germany were making their way back to the forces battling Japan, and the tactics and even strategies were being changed based on that information.
As far as any report from MacArthur, King in particular didn’t trust him, and all the individuals disagreed among themselves.
ETA, now I’ve skimmed the report, it was dated 28 May, 1945 and the number of estimated Japanese forces contined to grow over time as more and more units were transferred to Kyushu.
There were even questions if Operation Olympic, the invasion of Kyūshū, should be cancelled because of the higher number of estimated casualties.