When a piece of the sun struck Hiroshima on 6 August 1945, the world changed, never to turn back. The atomic genie entered our lives, and for good or evil it came to stay. In the words of William Laurence of the New York Times, an observer of the Hiroshima blast,
“At exactly 0815 this morning, Hiroshima stood out under a clear, blue sky. One tenth of a millionth of a second later, a time imperceptible by any clock, 45,000 inhabitants had been vaporized – men, women, children, their homes, deeply private possessions; the city had been swallowed by a cloud of swirling fire as though it had never existed. The best watches made by man still registered 0815.” [Edited]
One might ask if less cataclysmic alternatives were not available.
From 1937 to 1945, half the provinces of China and the whole of the American, British, French, and Dutch possessions in the Far East fell to Japanese conquest. The Imperial Army believed that the difficulty of piercing the defensive perimeter would cause the allies to lose heart and make peace. Japan would be in total control of the Southern Resources Area for which she went to war, and would concede a few islands in the defensive perimeter, by then redundant.
Several Japanese admirals favored negotiations for peace after the battle of Midway on 6 June 1942. Other officials joined the peace movement in July 1944 after the key loss of Saipan and penetration into the inner defense zone brought down the hawkish Tojo government. A transition government under Koniaki Koiso, inclined toward peace, struggled until April 1945 when the USSR terminated her 1941 treaty of neutrality with Japan. Baron Suzuki and a dovish coalition came into power, headed covertly by the emperor himself. But throughout, the real control of the government lay with the army.
Stalin played an important role in delaying any peace offer. Japanese leaders deluded themselves that they had a special relationship with the Soviet Union based on the neutrality treaty of April 1941; Stalin preyed on Japanese fears to prevent an approach to the western powers.
In late 1944 Premier Koiso planned to send Prince Konoye on a peace mission to Switzerland and Sweden. It came to nothing. A flurry of peace feelers to Portugal, Sweden, Switzerland, and the Vatican also failed. Because of fanatic opposition by the army and die-hards surrounding Emperor Hirohito, the trial balloons conveyed no government position, only a desire to end the war without sacrificing the dynasty. The only direct proposal to the United States came from Commander Fujimura, the Japanese naval attaché in Bern, Switzerland. On his own initiative in April 1945, he informed Allen Dulles, the U.S. intelligence chief there, that Japan desired negotiations toward surrender. He then reported to Tokyo that Dulles had originated the dialog. His frequent follow-up messages were suppressed by the navy and came to nothing.
National moods in the United States were anything but favorable to peace overtures. Xenophobia and revenge against the Pearl Harbor attack dominated American thinking. Seventy percent favored execution, imprisonment or exile of Hirohito; only seven percent favored retention. But heavy allied losses on Iwo Jima and Okinawa added to the growing desire to stop the killing and bring an end to the most terrible war in history. Nearly half the total American battle casualties in three years of war in the Pacific occurred in the first three months of the Truman presidency. Yet America's allies strongly opposed compromise on unconditional surrender. The Commonwealth nations had suffered extensively in the war, particularly Australia, and urged total surrender, sacrificing the dynasty, trial or execution of Hirohito, and harsh terms for the Japanese.
Preserving the dynasty was non-negotiable to the Japanese, but its importance was little understood in Washington or the allied capitals. In the United States, the failing hand of FDR and his demise in April 1945 created a deadly hiatus in American policy making. A tyro president and two successive secretaries of state with no experience in foreign affairs left American foreign policy at its weakest in the five months from Yalta to Potsdam. Yet Japan's peace feelers did elicit some response in high quarters as the costs of the war mounted. As early as May 1944, State Department officials led by the assistant secretary and former ambassador to Japan, Joseph Grew, sought to compromise unconditional surrender to allow retention of the dynasty. The JCS defined it as pointed essentially at the military, and that national suicide was not demanded.
A further boost to peace sentiments was provided when a naval intelligence unit led by Captain Ellis M. Zacharias, USN, with strong backing by Secretary of the Navy James Forrestal, was given authority to use psychological warfare against Japan by short-wave radio. This masterful campaign succeeded beyond expectations in setting the stage for a new Japanese attempt at peace. It influenced the 18 June peace message by Premier Admiral Suzuki asking Moscow to intercede with the U.S. on peace with assurance only on preservation of the dynasty. His appeal naively assumed that Stalin desired an early conclusion of the war in the Pacific. This demarche served only to force the Soviet dictator, whom a premature truce would have left fuming on the sidelines, to step up his plans for an attack on Manchuria.
The U.S. knew of Suzuki's cable through Magic. Perhaps there might have been a more positive response if sentiment in Washington had not come largely under the influence of the atomic bomb, soon to be completed. Both the U.S. and U.K. saw increasingly less to gain and more to lose in a negotiated peace. If negotiations meant peace without the bomb, the western allies no longer believed it to be in their interests. Thus both Stalin's striving to get into the Pacific war and the U.S. and U.K. striving to use the bomb meant that Japan's message came to naught.
In assessing the probably results of a positive U.S. response had specific Japanese overture been made, much, perhaps all, depended on the factor of time. It seems highly improbably that even modification of unconditional surrender and assurance of preserving the dynasty could have ended the war in late 1944 or early 1945. The Japanese popular delusion on the state of military affairs might have made it impossible for the still weak peace party surrounding the emperor to bring about a surrender. Very probably, as Hirohito later told MacArthur, there would have been a civil war and a wave of assassinations including the emperor himself. Elements of the army, augmented by countless fanatics, would continue to fight in the mountains and outlying islands. Such an eventuality, MacArthur claimed, would require doubling the occupation forces and ten years to master.
More realistic considerations govern the outlook concerning a possible conclusion to the war in June 1945, when Washington learned via the Suzuki cable of Tokyo's readiness to sue for peace. Had the U.S. interpreted unconditional surrender to allow retention of the emperor in June rather than July 1945, it remains likely, but far from certain, that the emperor and his confidants could perhaps have engineered an earlier surrender without an unmanageable army uprising. But it might have been touch-and-go. The Imperial Army had controlled Japan for 700 years and when in August the emperor made his unprecedented decision to order surrender, fanatic officers attempted a bloody coup to prevent his address to the nation.
Stalin was not yet able to enter the war on more than a token basis. Peace talks in June, to Japan's advantage, might have found him without a seat at the negotiating table. He would inevitably have shared, as would France and Britain, in the division of East Asia into spheres of influence. Without the bomb, without the precipitate demobilization of the superb U.S. war machine, the Russians might have achieved a stronger position in the Far East and weakened the American position worldwide. Those eventualities, however, depended largely on U.S. efforts to bribe Stalin to enter the war and avert the bloodshed in the invasion of Japan.
The JCS stated emphatically on 23 November 1944 that a Soviet commitment to enter the Pacific war was not only desirable but necessary for victory without the greatest bloodletting of the war in the invasion of Japan – perhaps a half million allied casualties. Before the Big Three meeting at Yalta in February 1945, the U.S. and British Combined Chiefs estimated the war would last eighteen more months. General MacArthur, slated for command of the invasion, considered it inevitable that the Soviets would take all of Manchuria, Korea, and possibly part of North China. He though the U.S. should press Russia to pay her way by invading Manchuria at the earliest possible moment, thereby tying down the Kwantung Army to prevent its use against the invasion. Soviet participation was seen as necessary as long as invasion appeared unavoidable – and until the bomb became a factor in the decision.
At Yalta Stalin made vitally important concessions toward setting up the machinery of the UN and agreed to enter the Pacific war two or three months after the German surrender. He had already been promised the southern half of Sakhalin island, the Kurile islands off Alaska, and a warm water port at the end of the South Manchurian railway at Dairen. The U.S. terms, unfortunately – based on faulty military intelligence, a grave underestimate of the effect of the atomic bomb and overestimate of the state of Japanese morale – were widely regarded as a sellout by the U.S. president. Roosevelt's decisions at Yalta at least hastened the fall of China into the Soviet orbit, and legitimized Soviet domination of liberated Eastern Europe, Poland, and the Baltic.
Unfortunately, President Roosevelt was negotiating from weakness. The U.S. forces in Europe were recovering from the German Ardennes offensive threatening Antwerp in December 1944. The Polish government in exile was sacrificed because Soviet army control made Lublin a de facto government. Soviet armies already had all the capitals of Eastern Europe in their hands and the three great capitals of Central Europe within their grasp. In the Far East, restoration of some Russian territories lost in the Russo–Japanese war of 1904-05 sought to create a Soviet bulwark against a resurgent postwar Japan – a bulwark much to be desired at that time. But these territories were available at any time to Stalin for the plucking. He needed little encouragement to go to war against Russia's historic enemy. He was driven to avenge Russian defeats by the Japanese; he had his own plans for Asia and entry into the Pacific war guaranteed him a seat at the peace table. With or without a territorial grab, it did not necessarily mean, then or later, that the USSR would have become a Pacific power.
The question again was the timing. The American desire to get a Soviet commitment worked almost in reverse. The long delay by the U.S. before opening a second front in Europe despite Stalin's pleading was believed by many, including Stalin, to allow the Soviet and German armies to bleed each other to death on the Central Front. The shoe was now on the other foot. Inviting Stalin to become a belligerent in Asia conceded him the initiative so that he could delay his entry until the last moment while the Americans bled.
What if FDR had offered no territorial concessions at Yalta? Allied submarine and air power had destroyed 93 percent of the Japanese merchant marine, but sizeable troop movements to Japan were believed to be neither possible nor necessary. Ultra portrayed a Japan in extremity but also showed its military leaders as being blind to defeat, bending all remaining national energy to smash the invasion of their divine home islands. Feverish efforts to withdraw men and material from Manchuria, Korea and North China produced seven new divisions in Kyushu between April and July 1945. Mobile combat strength almost tripled, soon outnumbering the Allied invaders at the critical landing sites, a cause for increasing concern by General MacArthur. Ordinary prudence seemed to dictate a need for a Soviet invasion of Manchuria to prevent Japanese withdrawals to beef up the home defenses. It also indicated a strong need for the USSR to enter the war in her own interest.
Other possibilities effected Soviet entry. Stalin had only 150,000 troops on the Manchurian border on VE day. If the war in Europe had lasted a few weeks longer, the Russian land armies could not have been moved to the Far East in time. Second, every day saved in rushing the A-bomb to completion brought the Japanese surrender a day closer. If the western leaders and their planners had been properly briefed on the bomb, the rudimentary Hiroshima gun-assembly type could have been rushed to completion and dropped well in advance of the Nagasaki plutonium type. Third, an earlier concession on unconditional surrender to allow retention of the dynasty would have brought an earlier surrender, probably without Soviet participation, without invasion, and perhaps without the bomb.
What if the Hiroshima bomb had been completed sooner? Shortly after Truman became president, the atomic bomb promised to become a major factor in making Soviet entry no longer necessary. All important problems of the two bomb types had been solved. But few people realized that the Hiroshima gun-assembly type, proven in the first chain reaction achieved in the Chicago Pile 1 experiment in 1943, needed no field test. Only the Nagasaki plutonium bomb was tested at Alamogordo. Lt. Gen. Leslie R. Groves, head of the Manhattan District which produced the bombs, promised Truman a 1 August ready date for both types. But Truman never knew that the Hiroshima bomb could have been ready possibly weeks earlier, before any likely date for a Soviet entry into the Pacific war.
The bomb caught the planners with their pants down. Vague details given the president, Leahy, Nimitz, and MacArthur were wholly inadequate. A formal role for the JCS was largely circumvented by Groves; secrecy and lack of imagination kept them skeptical or indifferent. If key officials including Combined Staff planners had been briefed adequately to develop operational parameters, plan to end the war and limit Russian gains in Asia would have been more advanced. Over-secrecy seriously limited political exploitation. Further, when a last minute glitch developed in the plutonium (Nagasaki bomb) detonator, the Hiroshima bomb was delayed until both were ready. With minimal knowledge at operational planning levels, invasion plans could have been scrapped, the first bomb readied, and a Japanese surrender demanded by late June or early July.
Laying like a palsied hand over American leadership in these critical weeks before Potsdam was the problem of obtaining political guidance on important issues relating to the war. If the new president were less heavily engaged in domestic problems, if issues in terminating the war had not have fallen to the free-wheeling Secretary of State James F. Byrnes, the path of history may have followed a different course. Byrnes neither welcomed staff assistance nor informed his subordinates that the war might come suddenly to an end. Washington was wholly unprepared for the overwhelming political and military problems on the eve of surrender. There was no approved surrender document, no surrender proclamation nor general order on urgent problems of how the allies, particularly the Russians, were to divide the Japanese empire during the initial occupation – matters of supreme importance to the future of Asia.
The Japanese proposal of 18 June referred to above sought Stalin's mediation of Japanese-American peace talks. Since the message revealed the abject condition of Japan and the Japanese belief that the USSR had no plans to enter the war, Stalin delayed several weeks, until the meeting at Potsdam, before informing the Americans. Since Truman had known of the offer through Magic, he realized that Stalin was foot-dragging to prevent peace negotiations until he could become a belligerent.
When Truman told Stalin on 24 July, also at Potsdam, of the new and unusually destructive bomb soon to be used on Japan, Stalin was non-committal. When the Hiroshima bomb fell on 6 August, however, he fully realized that the precarious condition of Japan, plus the A-bomb, might produce a sudden Japanese surrender with the Russians still on the sidelines. Quickly, and without notifying the allies, Stalin struck across the Manchurian border and declared war on Japan on 8 August.
Stalin claimed that the Politburo was concerned about the ghastly bloodletting in Europe and found little enthusiasm for a new war in Asia. Hence his eleventh-hour declaration of war on Japan sought to capitalize on a belligerent status in the peace negotiations with minimum bloodshed. If the Japanese fought with the same ferocity they had displayed at Iwo Jima and Okinawa, a surprise offensive against the 750,000 troops remaining in Manchuria risked disaster without major reinforcements from Europe. Yet if he stayed out completely, there was no basis in the peace negotiations for Truman to uphold the concessions made by FDR.
If Stalin had not entered the war, the bribe at Yalta would have been unnecessary. Since Soviet entry was important only as long as a U. S. invasion of Japan was un avoidable, the need for a Soviet attack on Manchuria ended either on 18 June 1945, when Japan asked the Soviets to mediate U.S.-Japanese peace talks, or a few weeks later, if the Hiroshima bomb had been used earlier. In either case, Japan would almost certainly have surrendered before Stalin entered the Pacific war, with consequent limitations on his postwar influence in Asia. A new vision would open for Harry Truman, soon to ride the atomic bomb toward a dominant American power position in Asia.
Had Stalin not entered the war, the tense balance in Asia promised new opportunities. Japan was prostrate; the European colonial empires were gone; China was in turmoil. Stalin's vision of the “Russo-Chinese Empire” of czarist days stimulated postwar political initiatives targeting China, Korea, and Indonesia. He wanted Sakhalin and the Kuriles to control the Okhotsk Sea and guard access of the fleet to the Pacific. His pet idea, the creation of a great navy in the shipyards of Japan, Manchuria and Russia, plus Japanese and German fleet remnants, promised expansion into the blue Pacific as a future naval power.
The U.S. Strategic Bombing Survey concluded that Japan would have surrendered probably before 1 November 1945, without the bomb, without Russian entry, and without invasion. There is little reason to question that judgment today. In P. M. S. Blackett's words,
“If the bombs had not been dropped, America would have seen the Soviet armies engaging a major part of the Japanese land forces in battle, overrunning Manchuria and taking a half million prisoners. All this would have occurred while American land forces would have been no nearer Japan than Iwo Jima and Okinawa. One can sympathize with the chagrin which such an outcome would have been regarded.1
If the A-bomb had not existed, the military effects of a possible delay in the surrender of a few weeks would have been minor. Unrestricted air and sea war plus mining of inland waterways, sharply increasing after May, would soon have cut off the home islands from significant movement of troops, food and raw materials and forced a surrender. The need for invasion would have passed and the added cost in allied lives, without the bomb, would have been superficial.
The political effects of the bomb in establishing an American postwar power role were far-reaching, however. Unrestricted use of the bomb against non-combatants raised serious moral questions. A Truman decision against its use, for legal or moral reasons, would have gained stature for American restraint but a major crisis in Washington would have erupted. The vengeful mood of the American people toward Japan, the enormous talent, treasure and resources spent in developing the bomb, the presumption of shortening the war and saving lives by its use, and the public outcry if the bomb were shelved left little room for maneuver. Insiders could not believe that “the world's greatest scientific achievement,” pursued with a maximum national effort, could be put aside while the war still raged.
Lt. Gen. Groves urgently sought operational use of both the Hiroshima and Nagasaki types and was scared the Japanese would surrender before both bombs could be dropped. He schemed to speed up the process before a possible surrender, even to the point of trying to circumvent the Joint Chiefs to do so. Use of both bombs was assumed by almost all – a decision without actually deciding – and never analyzed for the monumental short- or long-term effects. The bombs shocked the enemy into surrender and galvanized the peace faction around the emperor to intervene decisively in the peace process. Dropping the bomb shortened the war, gave Tokyo a face-saving device to surrender, and reversed the urgency to get Stalin into the war. It allowed Japan to face the new era as one nation under an emperor symbolizing unity. It changed the whole structure of postwar Japan. It prevented communism from sweeping through Japan and her conquests. It provided the leverage to obtain a postwar settlement largely on American terms, and it put new muscle behind the American power position worldwide.
What if only one bomb had been dropped? Several authorities noted that Japan's Supreme War Council was still split 3-3 after the Nagasaki bomb drop and claim that both were necessary. But on 8 August, on receiving the horrifying details of Hiroshima and before the Nagasaki bomb, Emperor Hirohito told Prime Minister Suzuki Kantoro that he wanted a prompt surrender “on whatever terms were necessary.” He prevailed over the cabinet dissenters in an unprecedented initiative to break the stalemate. It was his decision – to accept Potsdam but retain the dynasty – ratified unanimously by the full cabinet at 0300 on 10 August. President Truman had the news in Washington 21 hours later, at 0900 local time on the tenth and, while debating acceptance, sent a message to MacArthur and Nimitz to prepare for a sudden surrender.
The second bomb was not necessary. It merely compounded the destruction and loss of life, primarily for a combat test of a new weapon. The single bomb brought a quick surrender but it did not save the countless thousands of American lives often claimed. Before historians gained access to secret files, the myth of huge numbers of American, British, and Japanese lives saved had already achieved the status of accepted history. Recent analyses, however, found that the number of allied lives saved by the two bombs almost certainly would not have exceeded 20,000 and would probably have been much lower. The vaporization of a city was not a primary factor. Nevertheless, the shock effect clarified the issues, and, in Emperor Hirohito's quoted words, “gave us an excuse to surrender earlier without losing face.”2
At the last minute, use of the A-bomb might have been avoided by a Japanese surrender. The emperor deemed the Potsdam ultimatum acceptable from the beginning; on 3 August Prime Minister Suzuki and the cabinet advisors unanimously recommended acceptance. If Japan had been less lethargic in pursuing this last chance for peace, less obtuse in failing to recognize Soviet treachery, less naive in expecting Soviet mediation without a price tag, and less short-sighted in assuming that Stalin would favor keeping the emperor when toppling him was wholly in the Soviet interest, then hope could have stayed alive to avoid the atomic holocaust.
The Japanese response to the Potsdam ultimatum tied surrender to preservation of the dynasty. Had not an allied decision been forced as a condition of peace, would the dynasty have survived? Soviet pressure and American and allied public opinion clamoring for execution or imprisonment of Hirohito as a war criminal might have prevailed. Waves of fanaticism in Japan would spread turmoil through the Far East. Stalin's rampant march into Manchuria and Korea would have strengthened his demands for partitioning Japan with Russian troops sharing occupation duties. If no bomb had existed, the military effects of a few more weeks of war would have been minor. But the political effects on the American postwar role and her power position in Asia would have been far-reaching. It kept the emperor on the throne to preside over a unified Japan and pre vented the cancer of communism from paralyzing the country. A last-minute surrender might have prevented the bomb-but was not the world better served by its use?
Roosevelt and Churchill at Hyde Park in 1944 casually discussed a “non-combat demonstration” of the bomb but agreed that the idea was premature. A demonstration would have greatly reduced the loss of life, eased the surrender process, and achieved the same timely result at far less cost. Significantly, the stigma on the U.S. for a violation of the laws of warfare, or for using the bomb “only against Asians,” would not have arisen. If a demonstration were desired, some suggested avoiding public revulsion by bombing a desert or barren isle before the eyes of the allied nations. Some wanted a drop on an isolated Japanese forest such as Nikko or on the fleet remnants in Kure, to limit the death and destruction of non-combatants. Physicist Edward Teller suggested a high altitude night blast 20,000 feet over Tokyo where the awesome sound and light effects with minimal loss of life and property might have been persuasive. These suggestions were never considered seriously by policy makers.
For a demonstration to succeed, the desired psychological effect required direct visual evidence. The high altitude night blast over Tokyo would have maximized the number of observers whereas few in Hiroshima survived to tell the tale; reports trickling in to Tokyo carried little impact on people already devastated by more extensive loss of life and property in fire bombings. The Hiroshima blast destroyed communications with Tokyo immediately; the army tried to hide the ghastly evidence, refused to accept the bomb as atomic, and claimed to have countermeasures through proper shelters. Earthworms a few inches below the surface survived the atomic blast, they claimed.
The most practical type of demonstration received no consideration. If a prestigious international committee, including Japanese, had been invited to witness a special detonation of the Hiroshima bomb at Alamogordo – not the plutonium type actually tested there – what harm could have resulted? Would it have been better or worse if Japan knew? It was far too late for the Japanese to capitalize on any technical information gained; their own atomic research program long before had ended in disaster. Why should the United States waste time and resources on a demonstration overseas merely to tell Japan we had the bomb? An additional detonation using the Hiroshima type bomb at Alamogordo ran no risk of failure and would certainly have influenced the peace. If it failed, there was no uranium available for another Hiroshima type bomb and manufacture of two plutonium bombs would delay use until about September 1945. But because of excessive secrecy senior policy makers knew little beyond the mere existence of the bomb. The non-combat demonstration was dismissed erroneously as “unduly risky and not compelling.” Official Washington reached a virtually unchallenged consensus on targeting non-combatants in cities.
A deliberately targeted Japanese city, with prior warning, had been tentatively endorsed by Roosevelt and Churchill. Truman, however, feared that a warning might impel the Japanese to move POWs into the target area. He objected to using the bomb against civilians and opted for a drop, without warning, on a military target.
Would a nuclear demonstration be an effective deterrent in future crises? In the short term it might have ended World War II and soon been forgotten. But the ghastly loss of life and property at Hiroshima and the continuing hazard of radiation and genetic damage a half century later, unique in world experience, brought a revolutionary change in the relations of man to the universe etched indelibly on the human conscience. The stricken city became the world peace center where for almost 50 years, 1½ million visitors each year file past the perpetual flame, to burn until the last nuclear weapon disappears from the globe.
In sum, the various non-combat demonstrations discussed were never considered seriously by policy makers. The most practical idea was never thought of-inviting a prestigious international committee, including Japanese, to witness a test of the Hiroshima (gun type) device at Alamogordo. This type was not tested before dropping it on Hiroshima. It might have succeeded in ending the war. But more importantly, the ghastly loss of life and continuing horrors of radiation froze the experience in the world's memory as a vital and continuing deterrent to nuclear war. The horror of Hiroshima was a lesser price to pay for an everlasting deterrent than a far more catastrophic initiation into nuclear war at a later opportunity.
The Japanese people never experienced an invasion. Drops falling from the swords of ancient gods created the sacred Land of the Gods. But the calamitous Imperial Navy losses, plus the fall of the Marianas, Iwo Jima and Okinawa, changed invasion estimates from remote to inevitable. Japanese intelligence predicted an Allied assault before 1 November in the Kagoshima and Ariake Bay areas of southern Kyushu to gain naval and air bases for a knock-out blow to the industrial and political heart of Japan in the Tokyo-Yokohama area. This happened to be a precise who, what, where, when, and how of the allied plan.
Under the Japanese defense plan Ketsu-Go (“Operation Decisive”), 5,000 kamikaze and perhaps 3,000 conventional aircraft of varying airworthiness were dispersed at 70 airfields, 24 seaplane bases, and 200 concealed takeoff strips throughout Japan; 19 destroyer types, hundreds of midget submarines, and 2,000 small, fast suicide craft prepared to attack the invasion fleet at night. Makeshift floating bombs were ready at 98 secret Shinto bases. To save food and release prison guards for duty at the front, all U.S. and U.K. POWs were to be executed. Lastly, Japan had used chemical weapons against China and allied planners anticipated extensive use of biological weapons in the final campaigns. A shipload of plague-infested fleas and rats enroute to the battlefields of Saipan in July 1944 was sunk by the American submarine Swordfish off Chichi Jima with the loss of almost all hands. (None of the rats left the sinking ship.) One can only guess at the dire consequences had delivery been made. The vast Japanese biological warfare plant hidden near Mukden, Manchuria, allegedly had the materials to destroy half the people on earth.3
If invaded, the Japanese envisioned a whirlwind counter-attack engulfing the allies on the beaches; hourly waves of 300-400 kamikaze attacks would overwhelm the naval air defenses; 15 to 30 percent of the invasion fleet of 5,000 ships would be put out of action before the first American soldier hit the beach. (In the Okinawa campaign, 402 Allied ships were sunk or damaged by kamikazes – twenty times the naval losses at Pearl Harbor – and 10,000 killed or wounded, five times the Navy losses at Pearl). The 700,000 defenders were backed by the entire population prepared to die “at the water's edge.” Interlocking fire from high ground, camouflaged from air and sea observation, dominated the beaches. Critical hills were networks with tunnels, deep underground rooms, command posts, food and ammunition storage, even wells for fresh water. The ferocious defenses aimed to make the cost high enough in blood to force an allied withdrawal and a negotiated peace settlement. The entire nation would fight to the last ditch, then in the ditch with bamboo spears.
All Japanese planning emphasized the glory of suicide attacks. Home guards, including children, were trained in anti-tank war to throw themselves underneath advancing tanks with explosives strapped to their backs. (They were called “Sherman carpets.”) The emphasis was on death rather than defeating the invader. Yet despite a homeland army of 2,350,000 men and four million paramilitary fighters, accurate intelligence estimates, a clear terrain advantage, the kamikazes, and the tenacious qualities of the Japanese soldiers fighting for their homeland from fixed cave networks, the defenses were not as formidable as they appeared.
The buildup lagged. Chaotic Japanese logistics and lack of either a highway or rail network forced reinforcements to move by oxcart or human power over one-lane, rutted roads and mountain trails. Communications from division level used commercial telephones, below division level, runners or hand signals. The defense in depth created a tough outer shell but the impossible task of reinforcements and total lack of mobility over the mountainous terrain showed that once the invader cracked the shell, the battle was over. U.S. losses might have been catastrophic but the operation could not have been repulsed.
Could the massed Japanese build up have survived unopposed, pulverizing bombardment? MacArthur assured Marshall that the naval and air blockade would cut off all reinforcements or imports from China, Korea and Manchuria. ULTRA, however, disclosed that several army divisions left Manchuria and Korea for Kyushu from April to July 1945, and new divisions raised in Japan sharply increased the number of troops in Kyushu. But unquestionably allied air would wreak near-total havoc on the defenses in the three months remaining between Potsdam and D-Day, even without resort to nuclear weapons tactically, as General Marshall had suggested, to wipe out the defenses. The Japanese believed the invasion could not be repulsed. The leadership, including the war weary emperor, believed it would never take place.
Since the invaders could not be thrown back into the ocean, much of Kyushu would have become a vast American air and troop complex with major naval facilities at Sasebo for the final assault against Tokyo in March 1946. Beset by suicidal fanatics, guerrillas, and various other diehards, severe losses could be expected to the very last day of hostilities.
If the allies had invaded, the major unknown was the question of casualties. Could the promised bloodbath on the beaches of Kyushu force abandonment of the final phase, the invasion of Honshu to force a negotiated peace? At Yalta, FDR vaguely suggested a million, Churchill “a million American lives and half that number British.” To clarify his decision on the invasion, President Truman requested a study in June 1945 of the cost in money and people. For various reasons, the study was never completed. The Joint Chiefs estimated casualties for Kyushu in the range of 30,000 to 50,000 dead and 100,000 wounded. Admiral Leahy estimated losses at 35 percent of Okinawa's 63,000. The president, carrying the responsibility, was horrified by another planning estimate of 58,000 dead in the first eight days and by General Marshall's estimate at Potsdam of a quarter of a million American casualties before overcoming the last of Japanese resistance. American dead in all of World War II totaled 292,000; atomic bombing to force a surrender seemed far preferable to a Pyrrhic victory on the battlefield.
If the invasion were launched it meant committing major cleanup forces after the surrender to a ten-year war in the mountains. As part of the surrender terms, the Russians would expect to occupy Hokkaido. If the dynasty were not retained, the added consequences were unpredictable. Japan would be destroyed as a unified state with far-reaching effects on future Pacific affairs. Lastly, would the American people have sustained a prolonged and bloody campaign with victory so near at hand?
Would the invasion have been carried out? Hardly. The evidence strongly supports the USSBS (U.S. Strategic Bombing Survey) conclusion that Japan would have surrendered before invasion. On 7 June, Emperor Hirohito and the cabinet gave up on the idea of moving to the redoubt in the Nagano Alps to fight to the end, indicating perhaps that there would be no “final battle”; Japan would surrender first. On 18 June – the same day as the fateful telegram from Japan to Moscow asking Stalin to mediate a U.S.-Japanese peace – a crucial White House conference was called to develop the strategy for invasion. Truman approved the attack on Kyushu for 1 November but held in abeyance the decision on the Honshu phase. As the meeting was breaking up, Assistant Secretary of War John J. McCloy was asked for his views. He suggested that serious attention be given to a political solution to end the war. In the resulting turmoil, the president and Admiral Leahy supported his proposal. It carried the day and led to the Potsdam Declaration within six weeks. After the Potsdam ultimatum, invasion was no longer an alternative. With or without the bomb, a negotiated peace would end the most destructive war in history.
If early peace initiatives had generated an American response, it is quite likely that the war would have been foreshortened. Or perhaps the war could have been terminated sooner by delivering a surrender ultimatum after capture of Okinawa in mid-July and dropping the Hiroshima bomb as quickly as possible thereafter. Completion of the Nagasaki bomb might have been delayed as a result but the early drop would likely have prevented Soviet entry. As a non-belligerent, promises at Yalta conditional on Soviet belligerency would be out the window. Alternatively, had the Hiroshima bomb been used instead as a demonstration at Alamogordo for world leaders including the Japanese, it might have ended the war at a much reduced cost in lives, but it would not have been an effective deterrent to a future nuclear war in any way comparable with the catastrophe of Hiroshima.
1 P.M.S. Blackell, Fear, War, & the Bomb: Military & Political Consequences (NY: Whillesley House, 1949), 130, 137.
2 David Bercam, Japan's Imperial Conspiracy (NY: Morrow, 1971), 1041.
3 After the Saipan incident, the Japanese leaders became fearful of the threat of allied retaliation and, aware of her vulnerability, pledged not to use gas except in retaliation, recalled gas munitions from the field and allegedly stopped production and destroyed the entire CBW arsenal in Manchuria and scattered the people.