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Sunday, May 08, 2005

Atomic Bomb Section 1 Alternatives to dropping the atomic bomb / Casualty estimates for alternatives

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Section 1 Alternatives to dropping the atomic bomb / Casualty estimates for alternatives

Before discussing the alternatives, a short time needs to be spent on the goals. Depending on the desired outcome, there were various alternatives. President Roosevelt articulated his goal in 1943 in Casablanca. He first discussed General Ulysses S. “Unconditional Surrender” Grant. He said he was called this because he demanded nothing less than this from the Confederates at Vicksburg. He then said, “Peace can come to the world only by the total elimination of German and Japanese war power. The elimination of German, Japanese and Italian war power means the unconditional surrender by Germany, Italy and Japan. It does not mean the destruction of the population of Germany, Italy or Japan, but it does mean the destruction of the philosophies in those countries which are based on conquest and the subjugation of other peoples.”

Roosevelt, along with Churchill and Chang Kai Shek met later in 1943 to discuss the war against Japan. At this conference, the goals against Japan were more fully developed. The announced:

The three great Allies are fighting this war to restrain and punish the aggression of Japan. They covet no gain for themselves and have no thought or territorial expansion. It is their purpose that Japan shall be stripped of all the islands in the Pacific which she has seized or occupied since the beginning of the First World War in 1914, and that all the territories Japan has stolen from the Chinese, such as Manchuria, Formosa, and the Pescadores, shall be restored to the Republic of China. Japan will also be expelled from all other territories which she has taken by violence and greed. The aforesaid three great powers, mindful of the enslavement of the people of Korea, are determined that in due course Korea shall become free and independent.

So, seeing and understanding these goals, plans could then be formulated to accomplish them. Whatever the allies did, it needed to end with the unconditional surrender of Japan, something not easily accomplished considering Japan’s attitude towards surrender (see section 4). It placed a large burden on the military and military planners. This burden only increased with the fall of Germany. Now, the US was in a one front war and the people of the US were tired of it. They wanted the war to end, for them; it had gone on long enough. While the planners knew the hardest part of the war lay ahead, the people of the US didn’t want to hear it. They just wanted their sons home. This left the planners with horrific obstacles to overcome. But overcome they did and soon operation “Olympic” was born.

Before discussing Operation Olympic, I want to spend some time on the only other option readily available. That option was to completely blockade the home islands of Japan and continue to send B-29 bombers on conventional bombing runs. Some today feel this might have been the best option of the three, the most humane. It was felt that it would have quickly forced Japan to surrender or face “imminent starvation.”

During the first 6 months of B-29 bombing, 300,000 Japanese people were killed and 8 million rendered homeless. Even with this, planners could not come up with a decent estimate of just how long it would take to starve and bomb Japan into submission. The U.S. Joint Intelligence Committee (JIC) estimated that it would take many years for Japan to actually surrender. Japan would have become a nation without any large cities very quickly and those living in the cities would have suffered horrifically, but even as modern as Japan was, over half of its citizens lived and worked on farms. There were large areas under cultivation growing all kinds of vegetables along with rice. While the average Japanese person’s caloric intact was much reduced, imminent starvation was not to be seen. Planners just could not rely on this method to force Japan to surrender anytime soon. Thoughts of winning the war via blockage were soon scrapped and invasion plans drawn up.

Operation Olympic was to be the beginning of the invasion of Japan. Its goal was to take the island Kyushu. It was an ambitious plan, along the veins of the D-Day invasion. It would involve a massive amount of personnel attacking a rather small area that would be heavily defended. There was no real deception here. A massive attack was planned, and Japan, knowing what was coming, prepared a massive defense. In my opinion, if the atomic bomb had been unavailable and this attack occurred, it would have been one of the worst disasters ever in the history of warfare. I will expound on that in a bit.

Operation Olympic was only the first phase of what was to be the invasion of Japan. The operation in its entirety was known as Operation Downfall. Operation Olympic was the plan to take Kyushu followed by Operation Coronet, an operation to take Tokyo. The success of this plan was based on 4 assumptions.

  • The first was that Japan would fight to the death and that the US forces would no only face soldiers, but a ‘fanatically hostile population.’ From earlier operations, this was a given and not in dispute.
  • The next was that the attackers forming Operation Olympic would face only three Japanese divisions in southern Kyushu and three in northern Kyushu. That was a horrific underestimation of available Japanese forces.
  • The third was that Japan could only reinforce Kyushu with no more than ten divisions, another underestimation.
  • Finally, it was assumed that there would be no more than 2,500 Japanese aircraft to oppose the attacking forces.

Only the first of the 4 assumptions was close to being correct.

The invasion of Kyushu was planned to involve 766,700 US service men. There would be 134,000 vehicles and 1,471,000 tons of supplies. A truly massive undertaking. In comparison 150,000 men invaded the beaches of Normandy on D-Day while the initial invasion of Kyushu would involve about 250,000 men.

While discussing Operation Olympic, the subject of casualties needs to be broached. This is one of the most bitterly argued aspects of the decision to drop the Atomic Bomb. Those opposing it say the ‘true’ casualty figures were less than 100,000 and that this is all that Truman knew when he made the decision to drop the bomb. Unfortunately, most historians just don’t understand casualty figures, how they are produced or how they are to be interpreted.

Luckily for us, some serious investigation has been made into how casualty estimates are made, what numbers Truman had to refer to, how to interpret these numbers and how many historians have misinterpreted the number. For a full understanding of the numbers, I recommend the impeccably researched paper, “A Score of Bloody Okinawas and Iwo Jimas”: President Truman and Casualty Estimates for the Invasion of Japan by D.M. Giangreco as well as his “Casualty Projections for the U.S. Invasions of Japan, 1945-1946: Palnning and Policy Implications.” By reading these two papers, you will gain a better understanding of how the military comes up with the casualty number and how to read them for yourself. You will also find out that the military felt that casualties could have exceeded one million men. Yes, ONE MILLION MEN. I will state that I feel, from my own studies, that this number is still low. The one million men number is based on low estimates of the number of Japanese defenders as well as a low opinion of their fighting ability. I feel we could have lost many more men and just might have failed in our initial invasion. It could have changed history. (Please email me for help in obtaining these articles if necessary)

Much of this came to a head in 1995 during the abortive attempt to have an Enola Gay exhibit that was politically correct and would neither upset the soldiers that served nor the Japanese that lived through Hiroshima and Nagasaki. A truly impossible task. Those that were responsible for the exhibit took the politically correct route of basically denouncing the dropping of the bomb. In doing this, they used the often quoted number of less than 60,000 US casualties for the invasion of Japan. This far from the number of 500,000 above, again, one which I feel, from looking at what is available today, to have been a low estimate.

One of the most important tools in estimating casualties is comparing similar battles or situations and looking at the actual casualty numbers they generated. Below is a chart of battles the US military was using to make their estimates for Operation Olympic.


US casualties: Killed, wounded, missing

Japanese Casualties Killed and Prisoners

(NOT inc. wounded)

Ratio US to Japanese




1 : 4.6




1 : 5

Iwo Jima



1 : 1.25



81,000 (approx)

1 : 2

Normandy (1st 30 days)




New Guinea / Philippines



1 : 22

This chart and numbers were very disturbing for those trying to determine the casualties of the invasion of Kyushu. This chart was provided to General Marshall as he was meeting with Truman to determine how to handle Kyushu. The New Guinea / Philippines was an ongoing operation at the time and wasn’t considered comparable to what would be faced at Kyushu. Because of the uncertainty of the number of Germans killed during the Normandy invasion, there were no comparable numbers to use and it too was considered such a different war that its numbers might as well be meaningless.

There were other predictions made as to the number of casualties. MacArthur’s command determined there would be approximately 124,935 casualties by day 120 of the invasion. This did NOT include any Air casualties and, most importantly, any naval loses due to Kamikaze attacks, something we will discuss more in-depth later. Nimitz gave casualty figures as well, his included all branches of the military but he only tried to predict the first 30 days of battle. He came up with a total of 23,620 casualties in 30 day. General Marshall decided not to present any of these numbers at the meeting.

This meeting took place on June 18, 1945 at 3:30 pm. It is very important to note this because detractors of the bomb normally ONLY use this meeting to show that Truman was only informed of low casualty numbers. They discount ANY intelligence, of which there was a great deal, that was given to Truman after this meeting. Those attending this meeting were the Joint Chiefs of Staff, Secretary of the Army and Navy, Assistant Secretary of War John J. McCloy and Lieutenant General Ira C. Eaker.

At the beginning of the meeting, Marshall read excerpts from the report prepared for him dealing with casualties. He emphasized that the invasion MUST take place by November 1st or weather would force them to wait six more months. Marshall then read the following, “Our casualty experience in the Pacific war is so diverse as to casualties that it is considered wrong to give any estimate in numbers.” Then, disregarding any numbers that had been suggested by MacArthur or Nimitz, the above ratio chart was used. Marshall then used the Luzon ratio for predicting casualties saying there was much room to maneuver on Kyushu. Again, it was emphasized that at the most, we expected there to be 350,000 soldiers defending the island (remember the actual number unknown to them at the time was over 900,000). Using that ratio, between 70,000 and 280,000 casualties could be expected if, as had been the case in the Pacific to this point, nearly all the defenders had to be eliminated.

Like MacArthur in his estimate, Marshall failed to include any naval casualties. Another huge mistake as will be shown later. Even though his numbers were low, he felt that they were still quite difficult to bear. He hoped that Russia entering the war my persuade Japan to capitulate (wrong again) or that combined with the Americans attacking would cause their surrender. The other thing that he stressed was that implementing Operation Olympic did not force them to implement Operation Coronet, which decision could be made at a later time.

Admiral William D. Leahy, a member of the JCS, was the only one to speak up in opposition to what General Marshall said. He felt that General Marshall’s comparison of Kyushu to Luzon was incorrect and that a comparison to Okinawa would be far more accurate where 35% of the forces were casualties. This would put the casualties at 268,345, a number that was never voiced, something unnecessary considering these were all intelligent men who could do simple math. Again, this number was only an estimate and ONLY for Kyushu.

At the end of the meeting, Truman said he had asked for the meeting because he had hoped there was a possibility of preventing an Okinawa from one end of Japan to the other. He was clear on the situation now and was quite sure the Kyushu invasion should go forward and they could decide on final action later. Truman knew what they were in for, at least with the estimates of Japanese strength that they had at the time. He understood the difficulties and had a firm grasp on just how costly the operation would be in terms of casualties.

Secretary of War Stimson summed up his thoughts in a memo to the President after the meeting. He wrote:

There is reason to believe that the operation for the occupation of Japan following the landing may be a very long, costly and arduous struggle on our part. The terrain, much of which I have visited several times, has left the impression on my memory of being one which would be susceptible to a last ditch defense such as has been made on Iwo Jima and Okinawa and which of course is very much larger than either of those two areas. According to my recollection it will be much more unfavorable with regard to tank maneuvering than either the Philippines or Germany [because of the extensive network of dikes, canals, and rice paddies].

If we once land on one of the main islands and begin a forceful occupation of Japan, we shall probably have cast the die of last ditch resistance. The Japanese are highly patriotic and certainly susceptible to calls for fanatical resistance to repel an invasion. Once started in actual invasion, we shall in my opinion have to go through with an even more bitter finish fight than in Germany. We shall incur the losses incident to such a war and we shall have to leave the Japanese islands even more thoroughly destroyed than was the case with Germany. This would be due both to the difference in the Japanese and German personal character and the differences in the size and character of the terrain through which the operations will take place. (emphasis added by me)

I added the emphasis to what I feel is the all important sentence in this memo. It reinforced even more the amount of casualties he felt it likely the US would suffer in such an invasion. It should be remembered that taking Germany cost the US roughly 1,000,000 casualties. Since Stimson did not say he felt it would be comparable to what “Americans” suffered in taking Germany, we could interpret his statement as saying we would suffer casualties similar to those suffered by ALL the Allies in destroying Germany. If this were the case, his statement would be more inline with the feelings of former President Hoover.

During this time, former President Hoover sent a memo to President Truman. President Hoover had been, with the knowledge of the president, receiving full and classified briefings of the ongoing war and upcoming engagements. In his memo, Hoover advised President Truman to disregard the instructions of President Roosevelt and others and to sue for peace with Japan. While he felt surrender was necessary, he felt that an unconditional surrender was asking far too much and would end up hurting America. In his briefing, he estimated 500,000-1,000,000 DEAD, that puts casualties in the 2,000,000-5,000,000 range if the US continued on its present course and invaded Japan.

Outside of what was presented to Truman, there were various estimates as far as casualties went. It was these numbers that give us a better understanding of what the military was preparing for and just how serious they thought the fighting would be. In a document dated August 30, 1944, those planning operations against Japan estimated that about 3,500,000 Japanese troops would be available to defend the homeland. At that time, they had determined to use the recent US attack on Saipan to form a casualty estimate. This became known as the “Saipan Ratio.” The planners concluded, “In our Saipan operation, it cost approximately one American killed and several wounded to exterminate seven Japanese soldiers. On this basis it might cost us half a million American lives and many times that number wounded in the home islands.” These numbers roughly coincided with the memo Secretary Stimson sent to the president.

Using these figures, the military began to prepare for the upcoming operation. The Selective Service was notified of the high numbers of replacements that would be needed and inductions rose from 60,000 men a month to 100,000. The Selective Service planned for the war to run through 1946 and made preparations for it to go into 1947. They also began to increase the training centers, supply depots and medical facilities to handle this increase. The capacity of Army Ground Force replacement training centers reached a wartime peak of 400,000 in June 1945, nearly a month AFTER VE day. The entire nation was gearing back up for the most costly battles of World War II.

While some even then doubted the war would last this long, those that had to plan for extended manpower and medical services were getting ready for a long war. They weren’t pessimists, there is no record showing they doubted a US victory in the end, they were pragmatists. They looked at the numbers, the hard numbers generated from battles fought in the Pacific. What they saw were casualty ratios that were coming dangerously close to 1:1 the closer our troops moved towards the home islands.

As the time came closer for the battles to be fought, those in charge of public relations in the military had a problem on their hands. The backlash from a public hearing that another 500,000 to 1,000,000 might die was unthinkable. Therefore, they began to massage the numbers, they felt that the casualty numbers were far too pessimistic and that, as the battle continued, the US would swiftly learn how to cope with fighting the Japanese. They felt that while the first battles might have high casualty numbers, the survivors would learn from their mistakes and the ratios would fall to more acceptable levels. Without a shot being fired, these REMFs decided to present a best case scenario of 500,000 total casualties. This was a number that was felt to be acceptable to the US public as it was even lower than the already published number of needed replacements, that being 600,000 men. From that point on, despite what might be learned or surmised, the 500,000 total casualty number was used by any all public officials. While this number was used in public, the rest of the military continued to prepare for far worse.

So why do the estimated casualty numbers vary so greatly? One of the major reasons is the lack of information about how Japan would fight these final and decisive battles. It made 30 day projections incredibly hard and anything beyond that nearly impossible. There was just no way to know what would happen. Unfortunately, with the benefit of hindsight, it looks to be even worse than the most virulent nightmares the American leaders might have had at that time.

UPDATE: There was an article that I meant to mention and forgot to put in. As we have discussed the various branches of government and how they geared up for the invasion I forgot to mention one. That was the department in charge of war medals. As the invasion of Japan drew closer and casualty estimates were being produced, the agency in charge of medals had to make sure they were ready as well. 495,000 addition Purple Heart medals were ordered produced for the invasion of Japan.

Over 100,000 of those medals remain and are awarded today to soldiers injured in combat.

Continue to Section 2 Japan's Defense, What we knew then compared to what was reality