Invasion Most Costly

Recent defeats and the steady bombing of Tokyo were wearing heavily on Japan. Then, atomic bombs dropped on Hiroshima and Nagasaki hastened the end of World War II. Had that not happened 50 years ago this month, an elaborate U.S. invasion plan was in place. Based on casualty estimates, the Army ordered 370,000 Purple Hearts.

In 1945 the United States began planning a massive as­sault on the Japanese home is­lands. Beginning on 1 November, an assault force of 14 U.S. Army and Marine divisions was desig­nated to storm ashore on Kyushu, the southernmost of the home is­lands, in Operation Olympic.

And if Japan did not surrender, an even larger invasion of the main is­land of Honshu would begin in March 1946—Operation Coronet. Those would have been the largest amphibious landings of the war—much more massive than the Nor­mandy D-Day landings. The Kyushu invasion and, if necessary, the assault on Honshu in spring 1946, would have been the bloodiest battles of World War II.

The U.S. assault on Okinawa from April to June 1945 was to be the penultimate campaign of World War II, prelude to the final battle of the Japanese home islands. Many U.S. commanders believed that it would be a model for the in­vasion of Japan. The main island of the Ryukyu chain, Okinawa was only 350 miles southwest of Kyushu, within range of fighter aircraft based there. The island was Japanese territory, and the Okinawans were Japanese citizens, unlike the conquered peoples en­countered in most previous Pacific assaults.

Thus, the natives fought with tenacity. At Oki­nawa the equivalent of fewer than three Japanese divisions, with no possibility of relief or victory, heavily pounded by U.S. aircraft and naval bombardment, had held out for more than 100 days against a larger U.S. ground force with massive close air support. Both sides suffered horrendous ca­sualties. Even as the Battle for Okinawa was raging, evidence began to surface that the bat­tle for the home islands would be even more savage.

The U.S. decoding of Japanese communications—the Top Secret Ultra-Magic effort—indicated Japan’s preparations for the U.S. invasion: As Germany was about to fall, for example, the Japanese Army General Staff sent a message to the Japanese military attaché in Lisbon, Portugal, asking that the “battle of resistance” in Germany “be reported as fully as possible in order to furnish ref­erence material for the decisive bat­tle in our homeland and particu­larly for the training of special guard units and citizens’ volunteer units. ... In this way, we shall make firm our determination to defend the capital to the bitter end.” Magic was also intercepting diplo­matic traffic originating in Japan from representatives of neutral na­tions, information that was coming from relatively objective eyewitnesses in Tokyo. An intercepted message from the Portuguese Minister in Japan, for instance, said that “the fortification of coasts and moun­tains continues, giving the impression that this country, like Germany, is disposed to prosecute the war to its very end without the least probability of victory. ... A national guard is being organized to fight as guerrillas against the invaders.”

An intercepted dispatch from the Swiss Minister in Tokyo said that Japan “is still hoping to escape [defeat] by prolonging the war long enough to exhaust [its] ene­mies. Many eagerly desire the landing of the Americans in Japan proper, since they think it would be the last chance to inflict upon the Americans a defeat serious enough to make them come to terms.”¹

On 14 June, Fleet Admiral William D. Leahy, Chief of Staff to President Harry S. Truman, sent a memo to the Joint Chiefs of Staff saying that the President wanted to meet with them on 18 June “to discuss details of our cam­paign against Japan.” Truman, Leahy said, “expects at this meeting to be thoroughly informed of our intentions and prospects in preparation for his discussions with Churchill and Stalin.”

Truman’s intention, Leahy wrote, was “to make his de­cisions on the campaign with the purpose of economizing to the maximum extent possible in the loss of American lives. Economy in the use of time and in money cost is comparatively unimportant.”

For the 18 June meeting of the Joint Chiefs of Staff, General of the Army Douglas A. MacArthur, who would command the landings in Japan, sent his casualty esti­mates: a total of 95,000—dead and wounded—for the ex­pected 90-day campaign to seize the southern half of Kyushu.

“The foregoing,” MacArthur said, “are estimated total battle casualties from which estimated return to duty num­bers are deducted. Not included in the foregoing are non battle casualties which are estimated at 4200 for each 30 day period.”²

General of the Army George C. Marshall, the Army Chief of Staff, was not satisfied. A few hours before the scheduled meeting, he sent another message to MacArthur:

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 answer.³

MacArthur apparently only then appreciated the extreme importance that the casualty rates would play in Truman’s decision about the invasion. In his long reply, he back- pedaled from his original estimate, saying it had been “a routine report. . . for medical and replacement planning purposes.”

. . . The estimate is purely academic and routine and was made for planning alone. 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 [by the Soviets] 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.⁴

Two other documents pertaining to the casualty esti­mates were prepared for Truman. One put the casualties as high as 220,000; the other said casualties would be closer to those suffered in the invasion of Luzon—31,000. It was a remarkable discrepancy, and exactly what Tru­man would believe depended upon which of two prepared briefing papers he actually adopted.

Both top secret documents were entitled “Memorandum for the President Subject: Campaign against Japan.” The first one, dated 15 June 1945, and subtitled “Details of the Campaign against Japan,” was prepared by the Joint War Plans Committee, which, in a covering memo, “recom­mends that the enclosed memorandum be presented to the President at his conference with the Joint Chiefs of Staff, scheduled for 18 June. The covering memo went on to say that the committee “has assumed that the questions brought up by the President will be answered and discussed orally at the conference, and that the purpose of the memoran­dum is for the President to have available an aide memoire which he could examine at his convenience and possibly use at the forthcoming tripartite conferences [a reference to the Potsdam Conference].” The second doc­ument, also subtitled “Details of the Campaign against Japan” but originating with the Joint Chiefs of Staff, was dated 11 July—five days before the Potsdam Conference, which most of the Joint Chiefs attended.

A paraphrase of General MacArthur’s comments on the Kyushu operation (taken almost verbatim from his mes­sage to Marshall) repeated his recommendation that “no change in the operation” be made for the invasion of southern Kyushu. It also advocated the plan to invade Hon­shu and the Tokyo Plain.

The difference between the two casualty tables was as­tonishing. The first used broad experience and objective criteria as its guide. The second blatantly reflected MacArthur’s view of casualties as merely a U.S.-to-Japanese kill ratio. The table also gratuitously included a reference to D-Day casualties at Normandy—a reflection of one of MacArthur’s perennial criticisms: Allied con­duct of the European War. The second memo also showed that MacArthur—or at least MacArthuresque thinking— had already taken over the paper-pushing aspect of the in­vasion.

Of the many sets of numbers and arguments that would be presented to the President, the most honest were those that MacArthur gave in response to Marshall’s original message of 16 June. In it, MacArthur estimated that in the landing and three months of fighting on Kyushu, 94,250 men would be killed or wounded in battle, and another 12,600 would be felled by disease and accidents—a ca­sualty total of 106,850.

The 15 June Joint War Plans Committee (JWPC) memo offered three scenarios and three sets of casualty estimates. If the Olympic-Coronet plan went according to schedule, two landings would take place; together, they were ex­pected to yield 193,500 battle casualties. If, as some plan­ners believed, the Kyushu invasion ended the war, then the battle casualty count would be 132,500. The worst- ease scenario envisioned three major amphibious as­saults and the estimated consequence to be 220,000 bat­tle casualties. To all of these figures must be added the nonbattle casualties of accidents and disease. In that case, total casualties, in the triple-invasion scenario, would exceed 250,000 and might approach 500,000.

The casualty question haunted Truman as he considered his next moves in the war against Japan. In his view, he had only two choices: He could authorize the invasion or order the use of the atomic bomb, which, he knew, was nearing reality. And if the bomb failed or was delayed, then invasion was still an option. The casualty estimates from his military advisers would influence his decision Profoundly. Simply put, low estimates would give Mac Arthur and Marshall the invasion they and other Army leaders wanted. High estimates would make the invasion ^a far less attractive alternative to the bomb.

Navy leaders, mindful of the heavy toll kamikazes took °n their ships at Leyte and Okinawa, tended toward pes­simistic forecasts about the invasion. Leahy foresaw Okinawa-size casualty lists. Fleet Admiral Chester Nimitz, in a memo to Fleet Admiral Ernest J. King, Commander-in-Chief, U.S. Fleet, had said, “We must be prepared to accept heavy casualties whenever we invade Japan. Our Previous successes against ill-fed and poorly supplied units, cut down by our overpowering naval and air action, should not be used as sole basis of estimating the type of resis­tance we will meet in the Japanese homeland where the enemy lines of communication will be short and the enemy supplies more adequate.”⁵

Truman had stated his bomb-or-invade view in his diary on 17 June: “I have to decide Japanese strategy—shall we invade Japan proper or shall we bomb and blockade?” He seemed to have been referring to conventional aerial bom­bardment, but he also had to make a decision about S-1 (the code name for the atomic bomb, which, of course, he did not mention in his diary).

At 1530 on 18 June, Truman presided over the Japan­ese strategy meeting that he had requested through Ad­miral Leahy. Attending were Admiral Leahy, General Mar­shall, Admiral King, Secretary of War Henry Stimson, Navy Secretary James Forrestal, Assistant Secretary of War John J. McCloy, Lieutenant General Ira C. Eaker (representing the ailing General of the Army H. H. Arnold, head of the Army Air Forces), and Brigadier General A. J. McFarland, secretary to the JCS.⁶

Marshall opened the meeting by saying, according to the edited minutes, that “the present situation . . . was practically identical with the situation which had existed in connection with the operations against Normandy.”⁷ He then read, “as an expression of his views,” a memoran­dum prepared by the Joint Chiefs of Staff for the Presi­dent strongly urging that the invasion of Kyushu proceed as planned. “General MacArthur and Admiral Nimitz are in agreement” with the plan, the memo said.

As the group discussed casualties, Marshall told the President, “It is a grim fact that there is not an easy, blood­less way to victory in war, and it is the thankless task of the leaders to maintain their firm outward front which holds the resolution of their subordinates.” The invasion of Japan, he continued, “would be difficult but not more so than the assault in Normandy.” The original minutes quoted Marshall as saying that everyone going to the Pa­cific should be filled with the determination to see the plan through. This was later edited to read “should be indoctrinated with a firm determination to see it through.” (Several penciled-in changes were in the original minutes. A second, smooth copy was prepared, and it became the official minutes.)

Admiral Leahy spoke up to say that the President was “interested in knowing what the price in casualties for Kyushu would be and whether or not that price could be paid. Leahy also wanted to know how many troops would be used on Kyushu. (Stricken from the minutes was what had been the rest of Leahy’s sentence: “with a view to determining therefrom the number of casualties which might be expected.”) Leahy “pointed out that the troops on Okinawa had lost 35 percent in casualties.” He appar­ently based his figure on the casualties as then known. The final U.S. toll at Okinawa was 7,613 killed and 31,807 wounded, a total Army-Marine-Navy casualty toll ashore of 39,420. The assault force numbered about 100,000. So the actual casualty rate was more than 39%.

Admiral King assured Admiral Leahy that Kyushu would be different from Okinawa, because the only way to attack Okinawa was by “a straight frontal attack against a highly fortified position,” while on Kyushu, “landings would be made on three fronts simultaneously and there would be much more room for maneuver. It was his opinion that a realistic casualty figure for Kyushu would lie somewhere between the number experienced by Gen­eral MacArthur in the operations on Luzon and the Okinawa casualties,” or approximately 40,000 casualties.

General Marshall had just heard from General MacArthur himself that the “total force involved” was estimated as 681,000 with “one half engaged the first 15 days” for the landings, almost exactly the 340,600 figure. Using Leahy’s 35% es­timate on MacArthur’s 681,000 would mean that 238,350 Americans would be killed or wounded in battle. Using Mar­shall’s 766,700 figure, the theoretical ca­sualty estimate would be that much higher. No one pursued this arithmetic at the meeting, although the impression may have been left that U.S. casualties might reach as high as a quarter of a million.

President Truman continued the dis­cussion of casualties at Potsdam in July 1945. After learning details of the success of the atomic bomb test at Alamogordo, New Mexico, he met with his principal advisers—Stimson, Byrnes, Leahy, King, Marshall, and Arnold—on 22 July.⁸ Ap­parently at this meeting, Truman wrote, "I asked General Marshall what it would cost in lives to land on the Tokyo plain and other places in Japan. It was his opin­ion that such an invasion would cost at a minimum one quarter of a million casu­alties, and might cost as much as a million, on the Amer­ican side alone, with an equal number of the enemy. The other military and naval men present agreed. . . .”⁹

Arnold opposed the bomb, pointing out to Truman and others that Japan could be bombed into submission by B-29 attacks using incendiaries. “But none of the other military men—especially General Marshall—concurred with General Arnold. Anyway, my father saw that con­ventional bombing, even if it worked—and no one doubted that it might take months, even a year—would cause more Japanese deaths than the use of one or two atomic bombs, wrote Truman’s daughter, in an insightful biography of her father.¹⁰ This latest estimate of casualties added to Tru­man’s growing conviction about the need to use the bomb.

Thus, no simple answer exists to the question: How many would have died” if the war continued with U.S. landings on Kyushu, possibly followed by an assault on the main island of Honshu.

Truman’s memoirs say that General Marshall had told him an invasion of Japan “would cost at a minimum one quarter of a million casualties, and might cost as much as a million, on the American side alone, with an equal number of the enemy.” Secretary of War Stimson made a similar estimate in a postwar memoir. The numbers that General MacArthur submitted to General Marshall for the crucial 18 June White House meeting were well below Truman’s recollection of Marshall’s estimates.

For whatever reason, MacArthur’s figures were unre­alistic. But far more important is what MacArthur s own intelligence officers discovered after the war. From in­terrogations of high ranking Japanese staff officers, MacArthur’s O-2 staff reported:

The strategists at Imperial General Headquarters be­lieved that, if they could succeed in inflicting unac­ceptable losses on the United States in the Kyushu operation, convince the American people of the huge sacrifices involved in an amphibious invasion of Japan, and make them aware of the determined fighting spirit of the Japanese army and civilian population, they might be able to postpone, if not escape altogether, a crucial battle in the Kanto [Tokyo] area. In this way, they hoped to gain time and grasp an opportunity which would lead to the termination of hostility on more fa­vorable terms than those which unconditional surren­der offered.¹¹

The summons to the decisive battle was not just a pa­triotic shout. It was a strategy.

As the date for Operation Olympic approached, two U.S. Army agencies made independent estimates of in­vasion casualties. The Philadelphia Quartermaster Depot— which procured everything from combat boots to medals for the Army—ordered more than 370,000 Purple Hearts, expected to be awarded after the final battles for Japan.¹²

At the same time, on Luzon, the Sixth Army’s med­ical staff estimated that casualties from the Kyushu as­sault and subsequent fighting to secure the southern half of the island would cost 394,000 Americans dead, wounded, and missing.¹³ At Okinawa—in a battle that prof­fered many similarities to the fighting on Kyushu—the Tenth Army suffered 7,613 soldiers and Marines killed and missing and 31,807 wounded. Using that same 1-to-4 ratio for the Kyushu battles, the Sixth Army could ex­pect some 98,500 dead and 295,500 wounded.

Also using Okinawa as a model, where 4,907 U.S. Navy men were killed on board ships and 4,824 wounded, the Kyushu assault in the face of heavy air and undersea kamikaze attacks could have similarly inflicted ten times the number of naval casualties—on the order of 49,000 Navy men and troops on board ships killed and 48,000 wounded.

Thus, a reasonable casualty estimate of the Kyushu assault—based on medical staff estimates and not influ­enced by the politics of Mac Arthur’s headquarters or Washington—could have been on the order of 147,500 dead and 343,000 wounded. While these numbers are of a higher magnitude than those developed by Mac Arthur’s headquarters for President Truman’s meeting with the Joint Chiefs of Staff, the estimates were developed by medical specialists experienced in battle, men who had to be ready with blood and plasma, medical personnel, and evacua­tion spaces on ships. Even allowing a contingency mar­gin, the Sixth Army’s estimates must be taken seriously. Kyushu would have been the bloodiest invasion in his­tory. And it could have been surpassed by the assault of Honshu, which was planned to follow if the Japanese did not surrender by spring 1946.

Had the invasions occurred, they would have been the most savage battles of the war. Thousands of young U.S. military men and perhaps millions of Japanese soldiers and civilians would have died. Terror weapons could have scarred the land and made the end of the war an Ar­mageddon even worse than the devastation caused by two atomic bombs.

A third atomic bomb would have been ready to drop on Japan before the end of August, and another Japanese city would probably have been the target. More atomic bombs were in production. And from what is now known about Marshall’s thinking on the tactical use of atomic bombs, the plans for Operation Downfall would have been modified to include the use of atomic bombs in direct sup­port of the landings. Strong proposals also came from U.S. commanders to employ poison gas, crop-killing chemi­cals, and even biological weapons against the Japanese in an effort to hold down casualties. The devastation of Japan could have been total.¹⁴

And U.S. casualties in the invasion—or invasions— of Japan would have certainly been in the hundreds of thousands.

1 Magic Summary No. 1188, 26 June 1945, SRS 1710.

2 Gen. MacArthur message to Gen. Marshall from CinCAFPac to WarCOS, 17 June 1945, WD 1052 (MacArthur Archives).

3 Gen. Marshall message to Gen. MacArthur are from Gen. Marshall to Gen. MacArthur (Personal) 19 June 1945, WD 1056 (MacArthur Archives). The 19 June date appears twice on the message, even though the meeting Marshall refers to is 18 June.

4 Gen. MacArthur to Gen. Marshall (Personal) C-19848, 19 June 1945, WD 1057 (MacArthur Archives).

5 Ronald H. Spector, Eagle Against the Sun (New York: The Free Press, 1985), p­544. The memorandum is dated 28 April 1945.

6 Attendance at meeting from Truman Library, President Secretary’s Files.

7 Minutes of meeting held at the White House on Monday, 18 June 1945, at 1530 (National Archives).

8 There is confusion among the Potsdam accounts as to precisely when this meet­ing was held and who attended. See Margaret Truman, Harry S. Truman (New York: Morrow, 1973), pp. 273-274; and Foreign Relations of the United States: The Conference of Berlin (The Potsdam Conference), 1945, Vol. II, 243. Churchill joined Truman and his advisers at the end of this meeting (Winston Churchill, Tri­umph and Tragedy [New York: Houghton Mifflin, 1986], p. 638).

9 Truman letter to James Lea Cate, 12 January 1953, reproduced in Craven and Cate, The Pacific: Matterhorn to Nagasaki (Washington, D.C.: Office of the Air Force, 1953), between pages 712 and 713.

10 Arnold’s views are in Margaret Truman, 273.

11 Reports of General MacArthur, Vol. I, 418. The interrogated officers were LGen. Seizo Arisue and LGen. Torashiro Kawabe, deputy chief, Army General Staff.

12 Lt. David L. Riley, USN, in Uncommon Valor. . . Decorations, Badges and Ser­vice Medals of the U.S. Navy and Marine Corps (Hopkinsville, KY: [Privately printed], 1980), p. 3. Riley noted that “several hundred thousand” Purple Hearts were manufactured near the end of the war in anticipation of the invasion. It was from this World War II stock that medals were awarded in the Korean, Vietnam, and Persian Gulf wars and in all combat incidents since August 1945. The Air Force Association used this information as a gauge for estimating invasion casu­alties (The Washington Post, 26 September 1994). The public affairs office at the Defense Personnel Support Center (successor to the Philadelphia Quartermaster Depot) has stated that records showing the exact size and date of the order could not be found but that the size is such that all Purple Hearts awarded since the end of World War II came from that final order; an unknown number are still in stor­age. More than 370,000 Purple Hearts have been awarded since 1945.

13 U.S. Sixth Army, “Medical Service in the Asiatic and Pacific Theaters,” unpub­lished manuscript, Chapter XV (U.S. Army Center of Military History).

14 Marshall’s view of tactical atomic bombs is in Barton J. Bernstein, “Eclipsed by Hiroshima and Nagasaki: Early Thinking About Tactical Nuclear Weapons,” In­ternational Security, (Spring 1991), p. 168.

Mr. Polmar and Mr. Allen have collaborated on six books, the most recent of which is the new Code-Name Downfall: The Secret Plan to Invade Japan and Why Tru­man Dropped the Bomb (New York: Simon and Schuster, 1995).