Talk:Operation Downfall

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Unit 731

Did the U.S. know of the existence of this unit during planning for the attack or only after the war was over? Rmhermen 22:51, Aug 16, 2004 (UTC)

Further to this point, the quote is wrong on the name of the intelligence gained by SIGINT. Ultra was strictly from breaking the German enigma codes. Magic was a codename used for SIGINT from Japanese sources, although I'm not sure whether that referred to all Japanese-sourced SIGINT, or one of the military or diplomatic codes broken during the war. David Newton 00:21, 17 Aug 2004 (UTC)

Japanese forces

The info on Japanese defenses needs work.

From Downfall, p. 201-203

... At the beginning of 1945, the island was defended by only one field division, the 86th. ... Thus, when Truman reviewed the invasion plans [on June 18], Kyushu was known to be garrisoned by four divisions and two army headquarters.[A Japanese army being ~equivalent to a US Army corps.]

In July came the deluge. ... By July 9, estimates of total Japanese strength on Kyushu had already reached the 350,000 total Marshall had predicted would be the maximum the invasion would face. ...

... By August 10, the [JCS] estimated that by October 15, the Home Islands would house fifty-six field divisions, ... In the final revision of this estimate on August 20, the total on Kyushu [would have] reached 625,000 man and fouteen field divisions. (This total was exactly correct as to field divisions, but the actual number of Japanese servicemen on Kyushu [would have been] much greater: 900,000.)

p. 211

The intelligence revelations about Japanese preparations on Kyushu emerging in mid-July transmitted powerful shock waves both in the Pacific and in Washington. On July 29, [MacArthur's intelligence chief] Willoughby ... noted first that the April estimate allowed for the Japanese capability to deploy six divisions on Kyushu, with the potential to deploy ten. "These [six] divisions have since made their appearance, as predicted," he observed, "and the end is not in sight." If not checked, this threatened "to grow to [the] point where we attack on a ratio of one(1) to one(1) which is not the recipe for victory."

—wwoods 22:50, 14 Sep 2004 (UTC)

"Americans"

It seems to be typical of articles related to the Pacific War that authors often incorrectly refer to "Americans", rather than Allied forces. Apart from the issue of what an American is, I think this article overuses "Americans" as well. I mean if Operation Coronet had gone ahead, the Honshu campaign would have involved substantial non-US army (probably equivalent to at least two corps), as well as naval and air forces. What do others think? Grant65 (Talk) 23:28, Sep 14, 2004 (UTC)

Would you care to name a single major non-American unit scheduled to take place in either invasion? I have the order of Battle in front of me - Olympic was to be mounted by the American I, II, V, and IX corps, under Krueger. Coronet was to be mounted with the American I and 8 Corps. Meanwhile, in "The Invasion of Japan", the chapter named "Allied participation" says Unlike the war in the European and Medaterrain, the war in the Pacific was an American affair... Scenting victory in 1944-45, American planners and commanders were not altogether enthusiastic about letting Allied forces in on the kill. Churchill himself had only come to offer British forces only after long prodding from his own chiefs of staff. The prime minister preferred instead to use British naval power in the Indian Ocean and Southeast Asia to help recover Britian's lost colonies... American planners took no note that Allied ground troops might participate in the invasion of the Kanto plain. The published plans indicated that assault, followup, and reservce units would all come from US forces." It goes on to say that the Allies offered to send help, but the American planners were quite unethusiastic about it. In short, you are flat out, dead wrong. "Americans" is the proper word to use in this article. →Raul654 23:48, Sep 14, 2004 (UTC)

1. You are referring to one books'/historians' version of the "truth", and this is not good enough for Wikipedia. I think you need to look at more non-US sources. 2. The article even says non-US forces would be used (e.g. the bombers in Tiger Force). Amphibious operations are not just about soldiers, they are also about air and naval forces. 3. It's odd to speak of an "order of battle" for something which never took place. It's a proposed order of battle, concerning US forces only. Faced with casualties in the millions, how could the US high command have refused the offers of experienced Australian, Canadian, British and Indian army divisions? How is it that I have read in several sources that Macarthur agreed to the use of a token combined Commonwealth division, but the Australian government was contesting this, in favour of a whole Australian division? 4. It's simply wrong to say that the "the war in the Pacific was an American affair", even if one is speaking about the Pacific Islands campaign. A US-planned/commanded operation is not the same thing as an operation with exclusively US personnel. By the way, the focus on "British" forces — represented by "Churchill" — in that quote is revealing in itself. 5. Why is "American", which could mean Paraguayan, a better word to use than "US"? Allied is the right word in terms of the operation as a whole; US is the right word in terms of specific units and commanders.Grant65 (Talk) 00:54, Sep 15, 2004 (UTC)

Easy, easy. Grant's got a point. Code-name Downfall (Allen & Polmar) mentions "four British fleet carriers available in mid-1945 (and more coming out), ... The Royal Air Force (RAF) planned to shift heavy bombers to the Pacific, and a mostly Australian tactical air force was getting ready to support the Commonwealth Corps for the planned invasion of Honshu. ... The RAF was assembling the so-called Tiger Force of Lancaster Mark VII bombers, which would be based on Okinawa with Doolittle's Eighth Air Force. ... arriving ... about September 1945. Between 30 and 36 squadrons, each with 16 aircraft..." The Commonwealth Corps, aka the British X Corps, would have included the British 3rd Infantry Division, 6th Canadian Division, and 10th Australian Division. "The Commonwealth Corps was to have formed an afloat reserve for the Honshu assault. The British intended to provide two follow-up divisions on about Day Y+40." So only the Royal Navy was actually operating in the area before the Japanese surrendered, but if the war had continued through 1946, the non-American Allied forces would have made a noteworthy, if relatively small, contribution.

The British carriers had already taken part in the Battle of Okinawa. A combination of Google and Wikipedia tells me the carriers were Victorious, Illustrious, Indefatigable and Indomitable, as part of the US 5th Fleet.

—wwoods 01:10, 15 Sep 2004 (UTC)

I can vouch for the part about the carriers. Those British carriers helped in the invasion of Okinawa, and proved invaluable because of their steel flight decks (the American carriers used teakwood, which proved susceptible to kamikazes). →Raul654 01:13, Sep 15, 2004 (UTC)

Thanks, W. I have incorporated some of that information into a couple of other pages.Grant65 (Talk) 10:56, Sep 17, 2004 (UTC)

Prospects for Downfall

This section is rather speculative--necessarily, since the invasion didn't happen--but what's the "original research" that Raul objects to? [1]

—wwoods 20

52, 6 Jan 2005 (UTC)

Can you (or anyone else) cite a single reputable source that agrees with those speculations? Because the source I used to write this article does not agree with those conclusions at all. Quite frankly, it it sounds to me like whoever wrote it was making it up as they went along. It makes some pretty haughty conclusions with no evidentiary citation (that the japanese were going to surrender; that the invasion was going to be retargetted, when there is *NO EVIDENCE AT ALL* that that was going to happen, 'etc). →Raul654 21:18, Jan 6, 2005 (UTC)

Well, I wrote it, and I thought I threw in enough "likely"s and "unlikely"s to avoid sounding conclusive, much less haughty. :-)

Which source have you been using? I've mostly drawn from Richard Frank's Downfall; have you read it?

For the difficulties the Japanese were facing, from p. 350-352:

  Of this quartet [of events which were about to happen], without the atomic bombs, the new strategic-bombing directive of August 11 would have had the most significant effect. ...

  The redistribution of the fall 1945 harvest staved off the food-supply crisis to mid-1946. If bombing had disrupted this process, mass starvation would have been unleashed far earlier. As the new air-targeting directive promised to shatter Japan's rail system--the only means of gathering and distributing the harvest--this outcome appears likely.

I've already quoted stuff about the prospective Soviet invasion of Hokkaido in late August over on the Atomic bombings Talkpage.

For the difficulties the Americans were facing, I've previously quoted chunks about the Japanese buildup; see above. In the spring, the planners had assumed the invasion would be facing three Japanese divisions in southern Kyushu, reinforced by three from northern Kyushu and perhaps four from Honshu. By summer, there were facing nine in southern Kyushu, supported by four more in northern Kyushu. As you know, the rule of thumb is that the attacker needs a three-to-one advantage; that was gone. From p. 273-6:

... [On August 6], the Joint War Plans Committee of the Joint Chiefs of Staff forwarded a report, "Alternatives to 'OLYMPIC,'" ... An attached draft message to MacArthur and Nimitz observed that while the dramatic increase in Japanese strength did not yet require a change of the directive, ... It advised that "operations against northern Honshu, against the Sendai area, and directly against the Kanto Plain are now under intensive study [in Washington]."

  Nimitz had advised King "Eyes Only" on May 25 that he no longer supported an invasion of Japan, ... King now forced Nimitz either to avow support of Olympic (an action that can safely be ruled out, given the intelligence developments since May 25) or to break the apparent interservice consensus. [Nimitz waited to see what effect Nagasaki would have before responding.]

From p. 357:

  At this juncture, the key interaction would likely have been between Marshall and Truman. There is strong evidence that Marshall remained committed to an invasion as late as August 15. In his August 7 message to MacArthur, Marshall suggested the substitution of other locations for Kyushu, not cancellation. On August 13, General Hull, on Marshall's behalf, explored the use of atomic weapons to support a landing. [And, as the article already says, Marshall also considered the use of chemical weapons.] But tempering Marshall's personal commitment to invasion would have been his comprehension that civilian sanction in general, and Truman's in particular, was unlikely for a costly invasion that no longer enjoyed consensus support from the armed services.

So, all in all, it seems safe to say that before X-Day came in November, both the Japanese and American leaders would have been under extreme pressure to change policies, though God only knows how things would have worked out.

—wwoods 00:51, 7 Jan 2005 (UTC)

I personally think it's quite a stretch to beleive that two weeks prior to what-would-have-been the largest invasion in history, Truman would have called it off. Your own citation says as of August 6 (X-day - 3 weeks), the Joint Chiefs memo was advising no change of directive. On othe other hand, I have the same feeling that Japan would not have surrendered, because of the hard liners. Remember, these are the same folks who didn't want to surrender *after* the US dropped the atomic bomb on them and after their emperor told them to surrender (and, in fact, attempted a coup to prevent 'said surrender). Had the atomic bomb not been dropped, I don't think there's any way Japan would have surrendered prior to the Nov 1 invasion. →Raul654 03:49, Jan 7, 2005 (UTC)

Did you mean 3 months? X-Day was 1 November. That's enough time for things to change. With the Japanese people facing millions of deaths in the coming winter and the Red Army already invading the Home Islands, something would have to be done. The Japanese Army couldn't only keep on preparing to throw the Americans back into the sea. Meanwhile the Joint Chiefs weren't advising a change yet, but they were actively reconsidering their options, and with the Navy opposed to Kyushu, the plan would have changed somehow: more troops, chemical/atomic weapons, different target--something. And they didn't know it of course, but there was that typhoon coming in October.

—wwoods 04:49, 7 Jan 2005 (UTC)