Behind US Secret Invasion Plans for Japan
TWO months before the atomic bomb fell on Hiroshima, President Harry Truman secretly agreed to American war plans that would have launched the largest military invasion in history.Skip to next paragraph
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The objective: a full-scale, million-man attack designed to bring Japan to its knees.
While historians still debate the need to drop A-bombs on Japan, there is no argument about one possibility. If the US and Japan had locked in final combat on the empire's home islands, the fighting would have reached levels of ferocity never before seen.
Japanese wartime messages and military documents make clear that the nation's leaders were ready to sacrifice millions of soldiers and civilians, including women and children, in a desperate effort to stave off total defeat. The Japanese strategy was to inflict so many casualties by attacking vulnerable targets like US troop ships that Truman would drop his demand for Japan's unconditional surrender.
''If the invasion had taken place, it would have prolonged the war for over a year, turned Japan into a wasteland, and cost hundreds of thousands of American and Japanese lives,'' says Thomas Allen, co-author with Norman Polmar of ''Code-Name Downfall'' [Simon & Schuster, 1995], a just-published history of the final days of World War II in the Pacific. ''It would have been the bloodiest and fiercest battle in history.''
''Imagine the German casualties that would have resulted from an invasion of England, and you get an idea of how fierce the defense of the Japanese homeland would have been,'' Mr. Allen elaborates.
In preparation for a final assault on Japan, Truman ordered up 1 million soldiers, sailors, and marines, many redeployed from Europe, where the war against Germany had already been won.
Phase 1 of the ''Downfall'' assault, ''Operation Olympic,'' was to be launched on Nov. 1 against Kyushu, the southernmost of the Japanese home islands. Once taken, Kyushu was to be used as a staging ground for intensive air raids on the main island of Honshu.
Phase 2 of the invasion, ''Operation Coronet,'' was scheduled to be launched on March 1 against Honshu. To soften up the beaches, US military planners - unaware of the danger of nuclear fallout - contemplated using up to nine atomic bombs modified for ''tactical'' or ''battlefield'' use, according to Allen and Mr. Polmar.
In all, thousands of allied ships and aircraft, 5 million men on both sides, and dozens of US divisions - several times the number used to take Okinawa - would have been thrown into the months-long battle that US military planners estimated would have been the costliest in history.
From his headquarters in Manila, Gen. Douglas MacArthur warned his superiors of nearly 100,000 US casualties, including dead and wounded, in the first three months of the assault on Kyushu alone. United States Army medics independently estimated 394,000 casualties during the ''Downfall'' operation, while the Army Quartermaster Corps ordered up at least 370,000 purple hearts to decorate the anticipated dead and wounded.
For every American soldier killed, several more Japanese soldiers and civilians would have been lost, military historians say.
''We knew from our experience in Okinawa and Iwo Jima that there would have been very stiff resistance and heavy casualties, but much heavier casualties on the Japanese side,'' says Patrick Cronin, a senior research professor at the National Defense University in Washington.
With Japanese military codes long since broken, US military planners were able to track Japan's preparations to repel the first phase of the invasion, preparations that anticipated with remarkable accuracy where the main allied assault would occur.