The invasion of Japan never became a reality because on August 6, 1945, an atomic bomb was exploded over Hiroshima. Three days later, a second bomb was dropped on Nagasaki. Within days the war with Japan was at a close.
Had these bombs not been dropped and had the invasion been launched as scheduled, combat casualties in Japan would have been at a minimum of the tens of thousands. Every foot of Japanese soil would have been paid for by Japanese and American lives.
One can only guess at how many civilians would have committed suicide in their homes or in futile mass military attacks.
In retrospect, the 1 million American men who were to be the casualties of the invasion, were instead lucky enough to survive the war.
Intelligence studies and military estimates made 50 years ago, and not latter-day speculation, clearly indicate that the battle for Japan might well have resulted in the biggest blood-bath in the history of modern warfare.
Far worse would be what might have happened to Japan as a nation and as a culture. When the invasion came, it would have come after several months of fire bombing all of the remaining Japanese cities. The cost in human life that resulted from the two atomic blasts would be small in comparison to the total number of Japanese lives that would have been lost by this aerial devastation.
With American forces locked in combat in the south of Japan, little could have prevented the Soviet Union from marching into the northern half of the Japanese home islands. Japan today cold be divided much like Korea and Germany.
The world was spared the cost of Operation Downfall, however, because Japan formally surrendered to the United Nations September 2, 1945, and World War II was over.
The aircraft carriers, cruisers and transport ships scheduled to carry the invasion troops to Japan, ferried home American troops in a gigantic operation called Magic Carpet.
In the fall of 1945, in the aftermath of the war, few people concerned themselves with the invasion plans. Following the surrender, the classified documents, maps, diagrams and appendices for Operation Downfall were packed away in boxes and eventually stored at the National Archives. These plans that called for the invasion of Japan paint a vivid description of what might have been one of the most horrible campaigns in the history of man. The fact that the story of the invasion of Japan is locked up in the National Archives and is not told in our history books is something for which all Americans can be thankful.