Book Review: ‘Code-Name Downfall: The Secret Plan to Invade Japan-And Why Truman Dropped the Bomb’

Code-Name Downfall: The Secret Plan to Invade Japan-And Why Truman Dropped the Bomb (1995)

By: Thomas B. Allen and Norman Polmar

Publisher: Simon & Schuster

The Invasion That Never Was

In 1995, the Golden Anniversary of the Allied victories in Europe and the Asia-Pacific theaters of World War II, Simon & Schuster published Code-Name Downfall: The Secret Plan to Invade Japan-And Why Truman Dropped the Bomb, by Thomas B. Allen and Norman Polmar, the duo of military history writers behind the one-volume encyclopedia World War II: America at War, 1941-1945 and the novel Ship of Gold.

Based on extensive research about Operation Downfall, the massive two-phase invasion of the Japanese home islands of Kyushu and Honshu, Code-Name Downfall explores the various aspects of the American strategic plan to end the war with Japan as envisioned by the Joint Chiefs of Staff and the man who was to command this last great campaign: General of the Army Douglas MacArthur.

Additionally, the authors also examine the Japanese Imperial Army and Navy’s plans to defend the Home Islands from an American invasion, including the planned mobilization of almost every man, woman and child to build fortifications, serve as porters to carry vital supplies to the invasion areas, and – when the Americans landed on Japanese shores – fight alongside the military forces against the hated gaijin invaders in an all-out Decisive Battle intended to force the U.S. into a negotiated peace that would fall short of the Allies’ demand for unconditional surrender.   

From the Dust Jacket

What would have happened if atomic bombs had not been dropped on Japan in August 1945? Distinguished military writer historians Thomas B. Allen and Norman Polmar answer that provocative question in Code-Name Downfall, a vivid and dramatic narrative of America’s war in the Pacific, which would lead inevitably to massive amphibious assaults against the Japanese home islands. Based on newly declassified documents, personal interviews, and a decade of meticulous research, their book traces the progress of the Pacific War and reveals the top-secret details of the plans and preparations, on both the American and Japanese sides, for an invasion that would be far more complex – and costly in human lives – than the D-Day landings in France.

The Long Road to Tokyo

Although Code-Name Downfall is, at 351 pages, a slim volume for a subject that is both complex and thorny, it covers (albeit in broad terms) the entirety of the Pacific War from Pearl Harbor to Japan’s eventual surrender on September 2, 1945. The “narrative part” of the book takes 294 of those pages, while the remainder contains various appendices, notes and bibliography, and the index.

The Men from Shangri-La

The book begins with a prologue that describes the famous Doolittle Raid on April 18, 1942, just four months and 11 days after the Japanese surprise attack on Pearl Harbor and other U.S. bases on Oahu, Territory of Hawaii. In this daring mission, 16 Army Air Force B-25 Mitchell medium bombers, stripped of their defensive machine guns and fitted with extra fuel tanks for the flight to Japan, took off from the carrier USS Hornet and headed toward various targets on the home island of Honshu.

Because the American task force was spotted by Japanese picket ships 700 miles offshore – 100 miles farther out than Lt. Col. James “Jimmy” Doolittle and the raid planners had anticipated – the B-25s were launched earlier than plans called for. This had mixed effects on the raid: in Tokyo, the military establishment was aware that at least one American carrier was near Empire waters but too far out to launch its complement of planes, so when the twin-engine land-based Mitchells appeared over Tokyo and other cities in Japan, the defenders were caught by surprise.

However, because the B-25s had had to take off earlier than expected, they ran out of gas before they could reach bases in unoccupied China; most of the planes crashed in eastern China after their crews bailed out, and one Mitchell landed at Vladivostok in the Soviet Union, where its crew was interned since the Russians were not at war with Japan.

The Doolittle Raid did not inflict much physical damage on the Japanese war effort. However, it caused great consternation in the circles of the Japanese military rulers of the Empire, who had boasted that America would never bomb Japan. It also accelerated the Naval General Staff’s decision to approve Admiral Isoroku Yamamoto’s plan to invade Midway Island, an operation that many naval officers were initially skeptical about but now saw as a strategic necessity to prevent more U.S. attacks on the Home Islands.

As for the Americans, the daring raid raised morale at home after an endless string of Allied defeats at the hands of the Japanese. Though many details of the mission were classified until 1943 – President Franklin D. Roosevelt, when asked from whence the American strike had been launched, replied that the planes had taken off from “Shangri-La,” the fictional setting in the novel Lost Horizon – the news that Tokyo had been bombed electrified the nation. Pearl Harbor was now partially avenged; most Americans then living would not settle for anything less than total victory over Japan.

From Midway to Okinawa – and on to Downfall

Code-Name Downfall’s first five chapters summarize the three-and-a-half year-long war fought mainly by the United States and Japan in the Asia-Pacific theater, starting with a discussion on War Plan Orange, the strategic plan devised mostly by the U.S. Navy in the interwar period which Japan, America’s World War I ally, was seen as a potential enemy in a future war in the Pacific.

Due to the geographical reality of the region, the basic Orange plan – so named because American strategists assigned colors to nations that might go to war with the United States; Japan was assigned the color code Orange, Germany was Black, and Great Britain was code-named Red – was a primarily naval-centric strategy. Its “main theme” was a drive by the U.S. Navy and Marine Corps (with some support from the Army and Army Air Corps) across the Central Pacific. This westward movement would seize Japanese-held island bases in the Mandates (former Imperial German colonies in the Pacific ceded to Japanese “supervision” at the end of World War I). From these new bases, U.S. forces would then either reinforce American-Filipino forces who were holding off Japanese invaders or, in a worst-case scenario, liberate the islands from Japanese occupation. From there, the American armada would seek battle with the Japanese fleet and inflict such heavy losses that Japan either must surrender or be subjected to a long, debilitating naval blockade punctuated by air raids from U.S. bombers.

Before World War II, American planners rarely thought about invading the Japanese Home Islands; geography and local weather conditions favored the defenders, and in its long history, Japan had not been successfully invaded.

However, in 1942, even as Japan was on a seemingly endless streak of victories against American, British, Dutch, and Australian forces and occupying vast stretches of East Asia and the Pacific, U.S. war planners started work on a strategy that included a ground campaign on one or more of the four Home Islands (in addition to Kyushu and Honshu, Hokkaido and Shikoku were also considered as landing sites, even though they were less-than-ideal for military purposes).

Eventually, in parallel with the ultra-secret program to develop and build the first atomic bombs (code-named the “Manhattan Engineering Project” or simply the “Manhattan Project”), the war plans division, looking at the progress and tactics of the two competing U.S. drives across the Pacific commanded by Admiral Chester W. Nimitz (the Central Pacific campaign) and General MacArthur (the Southwest Pacific drive), came up with a basic “one-two” plan to invade Kyushu and Honshu if aerial bombardment or a naval blockade did not bring Japan to her knees once the Philippines were liberated and the Mariana Islands were turned into bases for American B-29 bombers tasked to bomb Japan with conventional bombs.

Most naval officers blanched at the prospect of an invasion of Japan and preferred a tight blockade of the island nation, while the air power visionaries of the Army Air Force, eager to form an independent Air Force along the lines of Britain’s Royal Air Force, were convinced that air power alone would assure a U.S. victory over the militarists in Tokyo without a single soldier or Marine having to fight on the beaches of Kyushu or Honshu.

However, General George C. Marshall, the Army Chief of Staff, and General MacArthur saw things differently, especially during the 1944 campaigns in the Central Pacific and the Philippines. If the loss of most of the Japanese fleet in the battles of the Philippine Sea and at Leyte Gulf had not convinced Japan that further resistance was futile, only one means would guarantee an American victory – Operation Downfall, the two-phased grand campaign planned and commanded by now five-star General of the Army MacArthur.

Between the Covers

Prologue: The Men from Shangri-La

Chapter 1: War Plan Orange

Chapter 2: The Bloody Road to Japan

Chapter 3: Winning with Air Power

Chapter 4: 350 Miles to Downfall

Chapter 5: Truman’s War

Chapter 6: Climbing Olympus

Chapter 7: The Enemy

Chapter 8: The Horror Weapons

Chapter 9: “I Have to Decide”

Chapter 10: “Land the Landing Force!”

Chapter 11: Objective: Tokyo

Chapter 12: Groping Toward Surrender

Epilogue: “Whose Son Will Die…”

Appendix A: Japanese Defensive Forces

Appendix B: U.S. Forces for the Kyushu Assault

Appendix C: U.S. Forces for the Honshu Assault

Appendix D: Redeployment of U.S Forces from Europe

Countering the False Narrative

In Code-Name Downfall, Thomas B. Allen and Norman Polmar follow both the progress of the Pacific War and the various steps that both the United States and Japan took to prepare for the final stages of their bitter and bloody war. With clear, concise, crisp prose, a fast narrative pace, and lots of research on the various aspects of Operation Olympic (the landings on Kyushu, tentatively scheduled for November 1, 1945, and the part of Downfall that was closer to fruition by August of 1945), Operation Coronet (the assault on the Greater Tokyo area on Honshu, scheduled to begin on March 1, 1946), as well as the various Japanese defense plans under the overall code-name: Ketsu-Go, especially Ketsu-Go 6, which was the defense plan for the Kanto Plain/Tokyo area.

Contrary to claims by critics of President Harry S. Truman’s decision to drop atomic weapons on Japan to persuade the Japanese government to surrender and thus avoid an invasion, the evidence from Magic and Ultra intercepts of enemy diplomatic and military communications in the late stages of the war shows that Japan would not surrender unconditionally per the Allied requirements to cease hostilities.

In Code-Name Downfall, Allen and Polmar explain that even though Japan’s senior military knew the Empire had lost its navy (the super battleship Yamato, one of the few capital ships still able to fight in early 1945, was sunk by American aircraft on April 7, 1945, during a last desperate sortie to attack U.S. ships in the early stages of Operation Iceberg, the invasion of Okinawa) and that American forces were getting closer to the Home Islands, they wanted to fight to the bitter end.

The authors also point out that Japanese war planners, including one officer who studied MacArthur’s tactics so closely that he had predicted where the Americans would land when the campaign in the Philippines began in the fall of 1944, correctly estimated where the invasion beaches would be. Thus, Imperial General Headquarters in Tokyo increased troop numbers in southern Kyushu – mostly by transferring units from the China-based Kwantung Army to Japan proper – and intensifying efforts to build defensive positions there.

As a result, even though MacArthur proclaimed Operation Olympic would succeed and often minimized the amount of projected U.S. casualties, the U.S. Sixth Army’s G-2 section (which was tasked with gathering intelligence and creating estimates of enemy strength and capabilities) realized that by November 1, designated by MacArthur as “X-Day,” instead of having a 3:1 numerical advantage over the Japanese defenders, the Olympic force of 14 Army and Marine divisions would meet a force on more or less an equal 1:1 ratio – which was not seen as a recipe for victory.

Allen and Polmar also explain – in great detail – how MacArthur’s ambitions for both military glory and a Presidential run in 1948 influenced his thinking about Operation Downfall. A conservative who despised Franklin D. Roosevelt, the Democratic Party, and the New Deal, MacArthur was Downfall’s most ardent proponent, insisting that it must be carried out regardless of the estimates of Japanese reinforcements to the Olympic invasion area.

A brave but vain man who was jealous of other generals – including his former subordinate, General of the Army Dwight D. Eisenhower – who had won laurels and popular acclaim on the battlefields of Europe against Hitler’s armies, MacArthur thought that the one sure route to the White House in the 1948 election was through a last grand campaign that would end the war with the seizure of Tokyo and the capture of Emperor Hirohito and the Supreme Council for the Direction of the War.

Among many revelations about MacArthur’s resentment toward Army generals who had served under Eisenhower in Europe: When Army Chief of Staff George C. Marshall, who was nominally MacArthur’s superior officer, suggested several officers, including Gen. Omar Bradley, George S. Patton, Jr., and Major General James M. Gavin, be given combat commands for Operation Coronet, which would be carried out by the U.S. First Army (which would be redeployed to the Pacific from Central Europe) and the Eighth Army, MacArthur refused. Bradley, who had commanded the 12^th U.S. Army Group from August 1944 to VE Day, would have to be content with command of a division, since there were no Army Groups in the Far East theater, and MacArthur did not wish to create them.

As for refusing to give Major General Gavin – who was the Army’s youngest general at the time – MacArthur reasoned that Gavin, who commanded the 82^nd “All-American” Airborne Division throughout much of the campaign in Northwest Europe, was a paratrooper. Since MacArthur had nixed any role for airborne operations in either Olympic or Coronet, there was no need for Gavin to be assigned a major command in the invasion of Japan.

Code-Name Downfall also delves into how difficult an invasion of Japan would have been, regardless of American air and naval supremacy on and around the landing zones. The Japanese code of “no surrender,” the mobilization and arming of millions of civilians, the vast arsenal of suicide weapons (including midget submarines, suicide boats called Shinyos, and 8,000 kamikaze aircraft) and the possible use by the Japanese of poison gas and bacteriological weapons would all combine to make Olympic and Coronet the bloodiest battles not just of the Pacific War, but of the entire Second World War.  

Estimates of the casualties on the American and Japanese sides – including civilians for the latter – varied, depending on which headquarters, including MacArthur’s, were doing the tabulation. But the most cited estimates foresaw one million American casualties (killed, wounded, or missing) and a ghastly 37 million Japanese casualties, most of them civilian.

Because Code-Name Downfall is a non-fiction book and not a fictitious alternative history novel, Allen and Polmar devote the last chapter of the book’s main narrative – Groping Toward Surrender – to how World War II in the Pacific really ended. Here, the authors describe not just how the success of the Trinity test of the atomic bomb spurred President Truman to use it as a means to avoid Downfall and end the war quickly, but also the Supreme Council for the Direction of the War’s reluctance to surrender after the first nuclear attack on Hiroshima.

The Japanese, contrary to the “Truman was wrong to drop the bomb” crowd, realized early on that the Americans had used an atomic bomb on Hiroshima because they, too, had been working on their own nuclear weapons program since the late 1930s. Luckily for the world, like Nazi Germany’s atomic weapons program, Japan’s efforts were “too little, too late,” and lack of resources and the destruction of the Japanese Army nuclear research lab by B-29 bombers in May of 1945 meant that no nuclear weapons would be available for use against an American invasion force by September of 1945. (When the Japanese physicists assigned to the naval A-bomb program reported this to the Navy, the response was, “then we’ll have one ready for the next war.”)

As shocking as the Hiroshima A-bomb was to the Supreme Council, the die-hard faction who wanted to hold out and force the Americans to invade believed it was a “one-off” and that the U.S. did not have any more atomic bombs in its arsenal. Thus, it was the twin blows of the Soviet Union’s entry into the war – on America’s side – and a second atomic bomb, this one on Nagasaki, that gave the “peace faction” of the Council an opportunity to convince the rest to accept the terms of the July Potsdam Declaration – with the proviso that Emperor Hirohito could stay on the Imperial throne.

There are, of course, some people who still claim that Japan would have surrendered in mid-1945 without either the use of nuclear weapons or a conventional invasion of the Home Islands. Some will claim that American officials, both military and civilian, created the “one million casualties” figure to justify the unjustifiable use of nuclear weapons. Some will even argue, as the authors of Code-Name Downfall point out, that the true objective of the Hiroshima and Nagasaki bombs wasn’t to get the recalcitrant Japanese military who ran Japan in Hirohito’s name to surrender, but to warn Joseph Stalin and the Soviet Union that America would use atomic bombs against Moscow if it tried to expand Communism outside the USSR’s sphere of influence.

This “Hiroshima and Nagasaki weren’t the last victims of World War II but rather the first of the Cold War” hypothesis is cute, but it does not reflect the situation in Japan and the Pacific at the time. It ignores that Japan was prepared to fight to the bitter end as long as it felt that Russia could be a neutral mediator in a negotiated peace that would allow the Empire to retain not just the Emperor as head of state, but some of its conquests in China and Southeast Asia. Additionally, the United States was eager for Soviet involvement in the Pacific War, although by July of 1945, seeing how Stalin had installed Communist regimes in Eastern Europe in the wake of its drive toward Germany in 1944 and 1945, Washington did not want Russian troops to land on Hokkaido or even get a sector of Tokyo like they had in both Berlin and Vienna.

Of the three non-fiction books about Downfall that I own, Code-Name Downfall is the first published. It’s also the briefest, although it covers many of the most important factors behind the decisions made in Washington and Tokyo in the last year of World War II. It does not have “inserts” with black-and-white photographs, but it does have a few photos, maps, and some drawings scattered throughout the book as Illustrations.

Code-Name Downfall was meant for the general reader and not specifically for the military history grognard, so the style of the book is to present information in a way that’s informative but not so technical or overstuffed with military jargon that the average person will be turned off and not want to read it. It’s well-written and factual, and it makes its points without resorting to hyperbole or falsehoods.

I don’t know if Code-Name Downfall is out of print; as of this writing the book is 28 years old and probably wasn’t a huge best-seller in 1995, but I found it on Amazon for $21.66 from a third-party seller, so there’s a good chance you can buy a copy in good to decent condition online.

If you are interested in World War II, American-Japanese relations in the 20^th Century, the Pacific War, or why Truman decided to drop the bomb rather than order a more conventional amphibious assault on Japan, Code-Name Downfall is a good introduction to these topics. The other books I own are a bit more detailed and cover some aspects of Downfall better than Allen and Polmar do here, but overall, I recommend this book.