Japan Fights On After Nagasaki: Or, What Do You Do With Your Nukes?

McPherson

Kicked
I wish I could believe that.

And no doubt I need a deeper dive into the primary source material. It's just that everything I've seen displays Dugout Doug unwavering in his downplaying of negative intelligence right down to the last day before the surrender; utterly confident in the success of an invasion, and minimizing of casualties. If his role as proconsul that would commence in the fall showed MacArthur at his best, his involvement with OLYMPIC/MAJESTIC consistently shows him at his worst. There remains room, which we can only speculate on, as to how he would have trimmed sail had the war continued; it's just that ALL the evidence we have suggests he would trimmed as little as possible. He wanted that invasion, and he wanted to lead it.

Whereas I can cut Marshall some slack on the tactical deployment of nukes because there were so many reasons to cut him, and pretty much any army officer at that point, slack. Marshall had known of the Manhattan Project for a while, but no one knew the full yield of the bombs, and he really had not had time to think about how they could be used. It was all unfamiliar terrain. How do you use these things? Where do you use them? We are the inheritors of the better part of a century of thinking about those questions.

But the real problem, as I sense you agree, was going to into Kyushu in the first place. It's such a violation of that sage old strategic axiom, "Hit 'em where they ain't." Cuz there were damn well *there*, in vast multitudes, growing by the week. It's understandable when you're rolling onto a postage stamp, or legal pad size, island, and you simply can't do without the postage stamp, but that wasn't the situation with DOWNFALL. Alas, while I can see a real fight brewing over MAJESTIC as it stood, I remain more skeptical that the Chiefs would resolve it by taking such a bold step as switching to Hokkaido. To stage the largest amphibious invasion in history without any land-based fighter (and limited bomber) cover . . . well, that might not violate quite as big an axiom as Hit 'em where they ain't, but it's awfully close. It's a shame, because it may well have been the most effective option on the table to set the stage for CORONET.
Then read this... from the citation above which was part of the estimate MacArthur had.

The Enemy Situation

A cardinal problem confronting General MacArthur before every operation was the question of enemy dispositions and capabilities in the projected invasion area. The following extracts from the intelligence estimate prepared for "Olympic" provide an excellent illustration of the comprehensive preparation and staff work that preceded a major military campaign. By the end of July, General MacArthur had a fairly complete picture of what to expect when his forces invaded Kyushu. To keep this picture up to date, new information was filled in as rapidly as it was received from the various intelligence sources.

1. ESTIMATE OF THE ENEMY SITUATION

a. Development of Ground Strength:
(1) The initial estimates on Kyushu of 24 March and 25 April 1945 considered an initial enemy deployment of six (6) divisions but seriously forecast a potentially larger deployment to ten (10) divisions, viz:
"Although the Japanese obviously regard the Tokyo Plain as the ultimate decisive battle ground, it is apparent that Kyushu is considered a critical sector on their planned Empire Battle Position. It is believed that plans will visualize assignment of about 6 combat divisions (plus 2 depot divisions) to garrison Kyushu initially and that they are prepared to expend up to 10 divisions, all they can tactically employ in the area to insure its retention. Depot facilities to maintain such a force would have been established in Northern Kyushu.
These divisions have since made their appearance, as predicted, and the end is not in sight. This threatening development, inherent in war, will affect our own troops basis and calls for special air missions. If this deployment is not checked it may grow to a point where we attack on a ratio of one (1) to one (I) which is not the receipt for victory....
b. ....
c. Development of Command Structure:
Recent information suggests the grouping of mobile combat units under 2 Corps Headquarters, one in Southern and one in Northern Kyushu. However, it is possible that with the considerable increase in strength in Southern Kyushu, a third
[414]​

Corps may eventually be formed.45
57 Corps: Established Headquarters at Takarabe (Miyakonojo Basin) during period April-June 1945. Believed responsible for defense of Southern Kyushu, i.e., of area south of central mountain mass.
56 Corps: Headquarters established at Iizuka (east of Fukuoka) during June 1945. Probably responsible for defense of area north of central mountain mass.
d. Organization of Volunteer Defense Units:
Information received since publication of the G-2 Estimate of 24 April 1945, indicates that the Japanese have materially accelerated their mobilization program and are now tapping a hitherto unused source of reinforcement, i.e., they are augmenting Army and Navy Units with large numbers of Volunteer Home Defense Units composed largely of partially trained reservists, over and above increments inducted into the actual armed forces. It has been estimated that approximately 125,000 of these are available in Southern Kyushu and approximately 450,000 in Northern Kyushu . Note the recent assignment of Major Generals as Commanders of 26 of the 51 Regimental Recruiting Districts in Japan, all of which were formerly commanded by Colonels, and of Lieutenant Generals of 10 other similar but generally more populous districts, suggests the grouping of these units of odd size and composition into divisions and possibly even into Corps. It is equally significant that these new Commanders have had recent frontline field commands. Credence is lent this theory by the recent sudden appearance in various parts of Japan of new divisions numbered in the 200 and 300 series whereas the highest previously identified divisional number was 161. Two of these new and unusually high numbered divisions, the 206th and 212th have appeared in
Kyushu .... (Plate No. 119)
e. Tactical Significance of Defiles:

(1) The rapidity with which the Japanese are
[415]​
Plate No. 119, Estimated Enemy Ground Dispositions on Kyushu, 28 July 1945

PLATE NO. 119

effecting their concentration in Southern Kyushu is undoubtedly influenced by the continued availability at full capacity of the two overland roads and railroad routes from Northern to Southern Kyushu. Although some of the incoming units may have arrived by sea and one (the 212th Division) was probably recruited locally, it is probable that 3 to 4 Divisions which are believed to have been activated by Depots in Northern Kyushu and Southwest Honshu utilized one or both of the overland routes. Also, in view of the fact that these troops must be maintained principally by the Kurume and Kumamoto Depots, the roads and rail lines have undoubtedly become vital supply lines. Concern of the Japanese as to the continuity of these overland lines of communications and recognition of their vulnerability to air bombardment is emphasized by recent initiation of Special AA Defense measures....
(2) Attention is invited to the following paragraphs of the G-2 Estimates of 25 April 1945 Par. 1e (4)
" These factors (detailed discussion of critical defiles traversed by east and west coast road and railroad routes from Northern to Southern Kyushu and the part-way alternate route Yatsushiro-Kokubu)-lead to the conclusion that the blocking of a limited number of defiles, i.e., destruction of critical bridges, tunnels, cuts, and fills, by concentrated aerial bombing and vigorous maintenance of interdiction by both air and naval bombardment will render it exceedingly difficult for the Japanese either to reinforce Southern Kyushu with elements of the Northern Kyushu Garrison, or to supply and maintain their forces which are in Southern Kyushu prior to the blocking of their only two lines of overland communication."
Par. 2 a (2) (c)
"Effective interdiction of both coastal routes and the alternate route from Yatsushiro through concentrated aerial bombing and/or naval gunfire would reduce overland reinforcement from Northern Kyushu to a mere trickle as long as maintained. Laborious passage of blocked defiles and long overland marches would be required.... It is probable that the Japanese may resort to night barge movement. An ample supply of small coastal craft is available and their tactics have long stressed the use of this means of troops transport.... Effective air and sea control should limit if not prevent the use of this method...."
Par. 2 a (2) (d)
"Reinforcement from Honshu: Troops from this source would probably be moved into Northern Kyushu via the Shimonoseki Tunnel or by night overwater movement; however, their subsequent movement to Southern Kyushu would be subject to the same restrictions that apply to Northern Kyushu garrison. Overwater movement across the Bungo Channel direct to Nobeoka or points south thereof should be easily prevented by air and/or naval action."
2. CONCLUSIONS

a. The rate and probable continuity of Japanese reinforcements into the Kyushu area are changing the tactical and strategical situation sharply.
At least six (6) additional major units have been picked up in June/July; it is obvious that they are coming in from adjacent areas over lines of communication, that have apparently not been seriously affected by air strikes.
There is a strong likelihood that additional major units will enter the area before target date; we are engaged in a race against time by which the ratio of attack-effort vis-a-vis defense capacity is perilously balanced.
b. The Japanese have correctly estimated Southern Kyushu as a probable invasion objective, and have hastened their preparations to defend it.
c. They have fully recognized the precarious nature of the land and sea routes by which they must concentrate and support their forces in Southern Kyushu. They are vigorously exploiting available time to complete the deployment and supply lines of strong forces in the area before they are deprived of the full use
of their limited lines of communication.
d. Since April 1945, enemy strength in Southern Kyushu has grown from approximately 80,000 troops including in mobile combat the equivalent of about 2 Infantry Divisions to an estimated 206,000 including 7 divisions and 2 to 3 brigades, plus Naval, Air-Ground, and Base and Service Troops. This rapid expansion within a few weeks' time, supply of this
[417]​

large concentration of troops, and the movement of defensive material has undoubtedly so strained the capacity of all existing lines of communication that any major interruption thereof would seriously reduce the effectiveness of the enemy's preparations. It is also probable that some of the new units identified in Southern Kyushu are not yet fully assembled and that at least one division (the 212th) which was probably formed of local volunteers has not yet been completely equipped.
e. The assumption that enemy strengths will remain divided in North and South (Kyushu) compartments is no longer tenable.
f. The number of enemy major units rapidly tend to balance our attack units.
g. The trend of reinforcements from North to South (Kyushu) is unmistakable.
h. Massing in present attack sectors is apparent.
i. Unless the use of these routes is restricted by air and/or naval action as suggested in Pars. 1 e (4) and 2 a (2) (c), and (d), G-2 Estimate of 25 April, enemy forces in Southern Kyushu may be still further augmented until our planned local superiority is overcome, and the Japanese will enjoy complete freedom of action in organizing the area and in completing their preparations for defense.
46
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That is what MacArthur knew, because his staff prepared those estimates and told him.. It was the basis for the USN's own reservations and reluctance to push forward. It was why King went to Marshall and why I suspect that Truman would order the other plan, the Hokkaido option, at the September review.

McP.
 
s
Oh, it's entirely a fair point. And I tend to agree. It is hard for me to see the Chiefs (or Nimitz, or MacArthur) taking such a bold (and risky) move. It would be somewhat out of character. Taking Saipan without land-based fighters is one thing. Landing in the Home Islands (and Korea almost counts as the same) is another.

The problem with the Kurils is that they'd already have to be moving on that in August, to allow enough time to secure and build up the air forces for any putative November invasion of Hokkaido. Which, of course, a Kurils operation would kinda tip off.

I have to say that, despite the ominous intel, and despite the Navy's reluctance, MAJESTIC would *probably* have gone ahead (with some modest tweaks), with the necessary delay after Typhoon Louise. I think there are plausible alternative timelines which do something else, it's just that, all things being equal, they are less likely.
So was checking around for any Allied plans (other then the blacklist series of plans) for invading Korea and I saw Google books reference to Richard B. Frank's book "Downfall" where on page 33 he wrote (When I get to access my copy again I must look at that chapter again):


"Korea , China , Hokkaido , and Kyushu became the focus of discussions for intermediate operations . Geography and the potential for “ major , costly and protracted land campaigns against large enemy ground forces ” ruled out Korea and China...."

And that these intermediate operations were envisioned as occurring between Olympic/Majestic and Coronet or securing additional areas from which to tightening the blockade and strengthen the bombardment prior to Olympic.

Hokkaido was favoured by the Army Air Force (either in lieu of Olympic or leading up to it) but the Navy disliked it because it invading Hokkaido would mean skipping Kyushu entirely (due to time and resources) and that this would throw away the advantages of the bases already secured in the Philippines and Okinawa. They also contended that this would throw away the superior strategic position of Kyushu (I guess the reference here is meant to be to Kyushu also offer sheltered harbours and bays from which the Navy could operate from in relation to Coronet).

So all in all it really seems like the options were going to boil down to Hokkaido or Kyushu and that before abandoning Kyushu, MacArthur and others would look at how atomic weapons might be employed to assist in the invasion and bring the advantage back to the United States.

Another factor to consider is that I doubt MacArthur would be ready to countenance any pre-Coronet operation that didn't invade the Japanese Home Islands at all. At this point he was very much fixed on getting onto Japan itself and I think that play out in his arguing (likely convincingly) against alternative operations in Korea or China.

At a guess I suspect Mac's preferences for pre-Coronet operations that were were Majestic or a Majestic alternatives would be:

1. Majestic - southern Kyushu
2. Nagoya (gets him on Honshu, can bisected Japan and enable a combined naval and land version of Coronet with land based forces from Nagoya advancing East on Tokyo)
3. Shikoku
4. Hokkaido
 
At a guess I suspect Mac's preferences for pre-Coronet operations that were were Majestic or a Majestic alternatives would be:

1. Majestic - southern Kyushu
2. Nagoya (gets him on Honshu, can bisected Japan and enable a combined naval and land version of Coronet with land based forces from Nagoya advancing East on Tokyo)
3. Shikoku
4. Hokkaido
Shikoku is another one that does not get adequate discussion.

Another factor to consider is that I doubt MacArthur would be ready to countenance any pre-Coronet operation that didn't invade the Japanese Home Islands at all. At this point he was very much fixed on getting onto Japan itself and I think that play out in his arguing (likely convincingly) against alternative operations in Korea or China.
In which he would likely be backed up by Marshall, for the same reasons Marshall fought British efforts to emphasize secondary operations in Europe over OVERLORD. "Go for the killshot. Don't mess around with lesser items."

In the end, of course, it would be Truman's call.
 

McPherson

Kicked
In which he would likely be backed up by Marshall, for the same reasons Marshall fought British efforts to emphasize secondary operations in Europe over OVERLORD. "Go for the killshot. Don't mess around with lesser items."

In the end, of course, it would be Truman's call.
Marshall was not always right. He passed Fredendall and he backed MacArthur.
 
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