Operation OLYMPIC vs Japan's Ketsu-Go
There have been several excellent studies done regarding the likely outcome of the planned American and Allied amphibious assault against the southernmost Japanese home island of Kyushu. This was Operation OLYMPIC, the first phase of the two-pronged final assault, Operation DOWNFALL (CORONET was the second phase). I recommend Edward Drea's article "Previews of Hell", Allen and Polmar's definitive book,
Code Name Downfall, George Feifer's excellent
Tennozan: the Battle of Okinawa and the Atomic Bomb, and my own book,
Endgame: America, Japan, the Bomb, and the Close of the Pacific War.
Japanese troop strength on Kyushu had actually grown to almost 600,000 by July 1945. While it is true that Japan as a whole was starving and sick and that most Japanese industry had long been smashed by B-29s, what resources remained were going almost entirely into the planned suicide defense against OLYMPIC. This was
Ketsu-Go, or Operation Decision. Without question, had the Allies and Japan come to blows as originally planned in these two operations, the result would have been the most horrific slaughter of the entire war, even worse than the Eastern Front conflict between Germany and the USSR. Because my time is limited tonight, rather than do additional original writing, I will quote from
Endgame, copyright 2001-2002, US Library of Congress, all rights reserved:
The Army and Marine combat troops making the initial landing numbered 340,600. Service and support troops which were to land following the initial waves numbered an additional 218,360, and there would also be 15,770 Navy personnel going ashore to provide support for the Kyushu armada. Navy and Army Air Force personnel pushed the total number involved to 766,700. But even this number does not give a comprehensive picture of just how great an effort OLYMPIC really was. In the Pacific, supply lines were orders of magnitude longer than those in Europe. One author says that for every American soldier in the field in the Pacific theater, there were 19 additional personnel required to put him there and maintain his presence there. If this is an accurate figure, the monstrous logistical nightmare facing the DOWNFALL planners becomes readily apparent. ﾂ"It is worth notingﾂ", George Feifer tells us, ﾂ"that ﾂ'serving' in 1945 was in most cases quite different from actually fighting. In many historical periods, authentic combat, the real thing, had been a relatively small part of military life, involving far fewer soldiers for far fewer days than the planning of itﾂ….only the men on (the) outer edges fell to bludgeons, swords, scimitars, and arrows. Technological development further reduced the proportion on the front lines, more sophisticated weapons requiring more personnel to service them. The greater the distance from the fighters' homes at which the battle was fought, the greater the numbers needed for transport, supply, and bookkeepingﾂ….Thusﾂ….each man at the front was supported by nineteen others, usually from a considerable distance.ﾂ" Given this ratio, the strength of the American war economy was truly mind boggling, and the expense of fielding large, technologically sophisticated, mechanized forces all but inconceivable. Despite this, incredibly, according to Leahy's memo, ﾂ"Economy in the use of time and in money cost is comparatively unimportantﾂ". What mattered to Truman was that he ﾂ"make his decisions on the campaign with the purpose of economizing to the maximum extent possible in the loss of American lives.ﾂ" (This is exactly what one would expect from this combat veteran President. The old artillery captain had seen war first hand less than thirty years before; he had even tried to volunteer for service in World War II and was turned down by General Marshall. Truman was a senator at the time he asked to serve and was quickly put in charge of the US Senate War Investigating Committee, which would go on to save millions of taxpayer dollars by policing against profiteering by weapons contractors.)
Exactly what casualty figures Truman was given at his meeting with the Joint Chiefs of Staff on June 18 has become a matter of confused debate. The first source of confusion was the previously mentioned communication involving Marshall and MacArthur between June 14 and June 18. Marshall first sent a message to MacArthur on June 16 asking for ﾂ"the estimate you are using for planning purposes of battle casualties in OLYMPIC up to D + 90.ﾂ" MacArthur replied that in the first 30 days, he expected that his forces would suffer 50,800 men killed and wounded, another 27,150 in days 30 through 60, and a further 17,100 in days 60 through 90. He added that ﾂ"the foregoing are estimated total battle casualties from which estimated return to duty numbers are deducted. Not includedﾂ…are non battle casualties which are estimated at 4200 for each 30 day period.ﾂ" MacArthur, then, expected that over 100,000 Americans would be killed or wounded in the battle for Kyushu alone. It appears that he did not realize at first just how significant the June 18 meeting would prove to be, because this comparatively blithe reply was immediately questioned by Marshall. On the 18th, just a few hours prior to the meeting, Marshall sent the following to MacArthur: ﾂ"The President is very much concerned as to the number of casualties we will receive in the OLYMPIC operation. This will be discussed with the President about 3:30 PM today Washington time. Is the estimate given in your (message) of 50,800 for the period of D to D + 30 based on plans for medical installations to be established or is it your best estimate of the casualties you anticipate from the operational viewpoint. Please rush your answer.ﾂ" MacArthur now tried to spin his earlier estimate by saying it had been ﾂ"for medical and replacement planning purposesﾂ" and ﾂ"a routine reportﾂ". He added, ﾂ"The estimate is purely academic and routineﾂ…It had not come to my prior attention. I do not anticipate such a high rate of loss. I believe the operation presents less hazards of excessive loss than any other that has been suggested and that its decisive effect will eventually save lives by eliminating wasteful operations of a nondecisive character. I regard the operation as the most economical one in effort and lives that is possible. In this respect it must be remembered that the several preceding months will involve practically no losses in ground troops and that sooner or later a decisive ground attack must be made. The hazard and loss will be greatly lessened if an attack is launched from Siberia sufficiently ahead of our target date to commit the enemy to major combat. I most earnestly recommend no change in OLYMPIC. Additional subsidiary attacks will simply build up our final total casualties.ﾂ"
In addition to MacArthur's estimate, there was at least one other formal report prepared for Truman by the same Joint War Plans Committee that was responsible for the plans for DOWNFALL itself. This was a Top Secret ﾂ"Memorandum for the President, Subject: Campaign Against Japanﾂ", dated June 15....It was estimated that in the two invasions, 40,000 Americans would die on the beaches, aboard ships, and further inland. Another 150,000 would be wounded, and 3,500 would go missing in action. The total figure was a staggering 193,500. The report also gave alternate figures for a campaign against Kyushu alone; in this case, 25,000 would die, 105,000 would be wounded, and 2,500 missing. In the worst case scenario, where there would be two Kyushu landings (the initial landing on the southern tip of the island and a second in the north) followed by the final assault on Tokyo, it would be 46,000 dead, 170,000 wounded, and 4,000 missing. It should be added that deaths due to accident and disease were
not included in these estimates. Disease was a real possibility with Japan's public health breaking down as its cities burned; there were as many as 13,000,000 survivors of LeMay's ﾂ"slaughter bombingﾂ" campaign (as the Japanese termed it) who were now homeless, and in their squatters' lean-tos and general filth, malaria and tuberculosis raged.
Another factor that was sure to drive up the total of dead and maimed Americans was the certainty that a disproportionate number of the OLYMPIC troops would be green rookies. It was common knowledge that many European veterans considered their job finished. Talk among some of them was near mutinous, and besides, under a point system that awarded credit for time served, most of these troops and pilots were long since past the cutoff number for getting out, which was 85. That some of them would be refused their promised exit from the armed services was a foregone conclusion, but many were already heading back to civilian life with the close of the war in Europe, and the Army in particular was loathe to but the brakes on too many of these men. Army planners stated bluntly that the loss of these veterans ﾂ"would mean loss of lives and battle efficiency.ﾂ"
Another casualty estimate came from Admiral Leahy. Leahy used the loss rates from the
Okinawa invasion to extrapolate figures for the OLYMPIC force. Of the total force, Army, Navy, Marines, and Army Air Forces involved at Okinawa, 12,520 soldiers, sailors, and Marines were killed. 36,631 were wounded, which meant according to American reckoning that they were hurt badly enough to be out of combat for more than a week. These 49,151 casualties were about 35 percent of the total force involved. Assuming the same rate on Kyushu, Leahy's estimate came to more than 250,000, with 65,000 KIA (Killed In Action). This put him somewhat at odds with MacArthur and his claim that Kyushu's much larger setting would allow greater maneuver and thus avoid some of the head on attacks of the Okinawa campaign, though of course MacArthur's figures still predicted horrific casualties. On the other hand, it would be hard to imagine that Japanese defenders would fight less hard or skillfully or fanatically on their home soil than they had at Okinawa, even if the preinvasion bombardment would be orders of magnitude greater. It must be remembered, too, that the Japanese 32nd Army on Okinawa was actually missing about half of its stockpiled ammunition---destroyed in an accidental explosion at a supply dump ---as well as its best unit, the 9th Infantry Division. This force was to have been positioned at the very heart of Japanese defenses on Okinawa, while other units charged the beaches as the Americans were trying to offload their men and equipment. Imperial General Headquarters miscalculated American intentions and in December 1944 sent the 9th Division to Formosa, from where it was to go to the Philippines. As it turned out, this crack 25,000 man unit would spend the rest of the war rotting away on Formosa because the high command feared submarine attack on the 9th's transport ships if they tried to complete their journey. As hard as it is to fathom, Japanese resistance on Okinawa would have been even more formidable if the 32nd Army had not been deprived of these experienced soldiers. Applying the absence of the 9th Division on Okinawa to Leahy's estimates of the casualties on Kyushu, then, means that the awful figures presented to Truman on June 18 were, if anything, probably much too low.
Americans would not be the only ones to die in the orgy of destruction. Japanese losses would be enormous. To continue with the Okinawa comparison, the force defending the 875 square miles of that island, the 32nd Army, was completely destroyed. Over 72,000 soldiers were killed, along with more than 30,000 Okinawans who had either been drafted into the Army or were serving as auxiliaries in one role or another. Only a few hundred were captured alive, many of them months or even years later as they wandered in from the countryside more dead than anything else. The kill ratio, then, was about ten to one. This would mean a minimum of 250,000 dead Japanese on Kyushu, and probably many more than that, given the Japanese buildup, the incredible firepower that America, Britain, and Australia were assembling for OLYMPIC, and the certainty that many Japanese civilians and paramilitaries would have charged into the fray to die ﾂ"honorablyﾂ". In fact, Japan was planning to expend all of its remaining military assets against OLYMPIC, except for the defenses of Tokyo itself. Preparations for Ketsu Go (Operation Decision) were well underway. According to American intelligence, American attackers would be faced by 350,000 Japanese troops, not counting huge numbers of paramilitary volksturm-style units whose effectiveness would have varied but who would certainly have caused additional losses. This was the accepted figure on June 18. It was much too low. More and more men and equipment were pouring into Kyushu all the time, even in the face of American air supremacy (which of course destroyed some of these forces and their transportation). Japanese forces on Kyushu actually built up to almost 600,000 troops by late July. On July 29, MacArthur's own intelligence organization, known as G-2, said, ﾂ"The rate and probable continuity of Japanese reinforcements into the Kyushu area are changing that 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 the target date; we are engaged in a race against time by which the ratio of attack effort vis-à-vis defense capacity is perilously balanced. Unless the use of these routes is restricted by air and/or naval actionﾂ…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.ﾂ" Marshall was so worried by this buildup that he suggested MacArthur consider other landing sites; alternatives proposed in this ﾂ"eyes onlyﾂ" message included the city of Sendai, 180 miles north of Tokyo, the town of Ominato, located on Mutsu Bay on the northern tip of Honshu, and Tokyo itself. MacArthur rejected this notion because he felt that American air power would prove decisive against even a large Japanese buildup and in any case felt that taking the southernmost home island was critical because only then could local, land based air power be used in the final assault on Tokyo to the north. It is doubtful MacArthur really had a good grasp of just how many enemy personnel his forces would face. Japan was ﾂ"systematically mobilizing a vast manpower pool---in addition to its military force---of 13.3 million males aged 15 to 59ﾂ….Special Guard Forces, made up mostly of men who had some previous military trainingﾂ…were attached to major units primarily for such non-combat duties as fortification building, transport, and ﾂ"casualty clearingﾂ" on the battlefield.ﾂ" But of course all of these would be expected to fight; every man, woman, and child would be infantry in the end. In fact, Japanese plans were even more explicit than this. On April 20, Imperial Army General Headquarters issued its ﾂ"Decree of the Homeland Decisive Battleﾂ", which said in its opening statement, ﾂ"We shall throw everything conceivable, material and spiritual, into the battle and annihilate the enemy landing force by fierce and bold offensive attacks.ﾂ" ﾂ"Everything conceivableﾂ" would include the last remnants of the Imperial Navy, that is, about 20 destroyers and 40 to 60 fleet submarines, none of them with any more fuel than for a one way ride to glory; 540 five man midget submarines and at least 360 two man midgets; and hundreds of suiciders that were nothing more than warheads mounted on speedboats. (Though of course, all of the seagoing units were really suiciders.) There were even hundreds of suicide divers, whose task was to swim out from their underwater warrens and fling their explosives-laden bodies directly underneath oncoming landing craft. From the skies would come as many as 10,500 kamikazes who would expend
all of their strength over the first ten days of battle. That Japan was husbanding its last ergs of strength for the OLYMPIC assault is evidenced by the fact that during the combined air and battleship bombardments of July and August, 1945, the Japanese rarely even tried to mount any effective naval or air opposition, not even kamikazes.
The entire strategy from top to bottom was, in fact, suicide by Western standards, but according to Major General Masakazu Amano, chief of the Army operations section at Imperial General Headquarters, ﾂ"ﾂ…we were absolutely sure of victory. It was the first and only battle in which the main strength of the air, land, and sea forces were to be joined. The geographical advantages of the homeland were to be utilized to the highest degree, the enemy was to be crushed, and we were confident that the battle would prove to be the turning point in political maneuvering.ﾂ" A July 1945 IGHQ memo reflected this thinking, stating hopefully that Japan's last throw of the dice would produce at least a million US casualties---even if it cost an equal or greater number of Japanese. The hoped for result would be ﾂ"public opinion in America (becoming) inclined towards peaceﾂ…with comparatively advantageous conditions.ﾂ"
In other words, the Japanese plan was to force a favorable negotiated peace on Japanese terms, and any amount of bloodshed was simply the necessary price.
In a footnote, I added the following, which in my view is much the more likely outcome:
The figure of 250,000 Japanese dead is based on the low end Joint Chiefs estimate of 25,000 American combat deaths, times ten, again using the approximate Okinawa kill ratio of ten to one extrapolated onto the Kyushu landing. However, the following factors must be kept in mind when calculating likely OLYMPIC-Ketsu Go casualties. First, the JCS figure was based on the assumption that opposing Japanese forces would number 350,000, when in reality they would have been nearly twice that size,
not counting air and sea kamikaze, quasi-military, and nominally civilian assets. Second, very few Japanese, especially regular Army and especially on their home ground, would ever have surrendered or been captured alive. Third, American and Allied supporting firepower (especially naval and air) would have been the very greatest possible within the framework of existing technology and logistics. There were also contingency plans to employ poison gas, especially if IGHQ had resorted to such weapons. (See Allen and Polmar, 172-191.) All in all, the real figures would certainly have amounted to better than 500,000 Japanese killed in action, and American casualties would also have been much worse than the JCS predicted.
With all of this taken into account, I don't know how anyone can argue that the atomic bombings were not the fastest and most humane (in terms of lives lost) means of ending the War. --- WJP