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May 20, 2024

Operation Downfall

By Van Lee

Operation Downfall: The Greatest Invasion to Never Happen

When people speak of World War Two their first thoughts usually stray towards Germany and the invasion of Europe. They think of great battles such as the Battle of Britain that pitted Great Britain's fine young men against German pilots intent on paving the way for a German invasion of the British Isles. Many think of the Battle of the Atlantic, which saw the German Wolf Packs (the term used to denote German U-boat groups) hunting down Allied merchant ships. And many think of the invasion of Normandy, commonly referred to simply as D-Day. But the war with Germany was only one theater of action during the war. There was also the Pacific Theater.

While for our European brethren, the European Theater may hold greater significance, for Americans, the Pacific Theater holds equal significance. For many it holds even greater significance. For one reason, Japan was the only foreign power to ever successfully launch a military attack on the United States. And beyond that, many had family members who went to war against Japan. To many of them, the war against Hitler was just another news story. To them, the real war was with Japan. My father was one such person. He served in the Marine Corps and saw action in Okinawa and in Saipan. Okinawa and Saipan were just small islands in the middle of nowhere, but they were strategic in value. They were stepping-stones to Japan.

From the beginning, U.S. military planners realized that the war with Japan would consist of numerous small actions (in comparison to what would take place in Europe) due to the fact that Japan was an island nation and they occupied dozen upon dozen islands throughout the Asian waters deep into the Pacific Ocean. While all the islands seemed important to Japan, U.S. leaders realized that there wasn't a need to conquer each and every island. The idea was to capture an island and set up a base of operations. This would allow Allied aircraft to be supplied and fueled there and for troops to be stationed for the next island that needed to be conquered. Instead of moving to the next island, which might only be a few miles away, they would jump to the next island that the aircraft could reach and be able to return from. That island would then be invaded. The islands in between the previous one and the new one would simply be cut off from Japan and left to "whither and die" as their supplies dwindled. For a child, the term "leap-frog" is a term for a game to play. For the man of the Marines, Army and Navy, the term meant they could avoid many islands and reduce needless bloodshed.

The capture of these particular islands was necessary to win the war. While U.S. leaders recognized that most of the war would be fought in small invasions of tiny specks of land dotting the ocean, they also realized that ultimately, it would have to be capped off with a large invasion of mainland Japan. This planned invasion was called Downfall, and military planner expected it to be a colossal engagement with casualties estimated into the hundreds of thousands.

There were only two suitable areas on mainland Japan from which an invasion could be launched. The first area was Kyushu, the southernmost island of Japan, and the other was Kanto, a plains region south of Tokyo. Since those were the only suitable areas, it was easy for the Japanese to plan for an invasion. Military planners estimated six divisions to be at Kyushu (three in the north and three in the south) and twenty-one divisions on Honshu (the larger Japanese mainland island) with fourteen of them already along the Kanto plains. This doesn't take into account troops in other locations and civilian forces that could be called upon when needed. And if these divisions followed the same patterns as the Japanese forces engaged on the other islands, they would fight to the death down to very end.

Those numbers were conservative. As the time of the actual invasion drew near, intelligence suggested that there were more Japanese ready for the invasion then they thought. In fact, radio intercepts showed that there were nine divisions in southern Kyushu alone where previous estimated had showed three. In reality, even these figures were much smaller then the actual number of troops there.

Based on the numbers of Japanese troops they believed were available to repulse an invasion and on the brutal fighting spirit they had shown in previous engagement, military planners estimated nearly 500,000 casualties in the invasion of Kyushu with over 100,000 fatalities. For the invasion at the Kanto plains, they estimated 1.2 million casualties with over 260,000 fatalities. To put that in perspective, overall in the war, including both the war in Europe and the Pacific, the U.S. suffered a little over a million casualties with around 300,000 deaths. Operation Downfall, if even close to military estimates, would account for a greater number of American casualties then all the rest of WWII combined.

The invasion at Kyushu was to be called Operation Olympic and was scheduled for November 1, 1945. It was designed as "X-Day" (Operation Downfall itself held the designation of "D-Day"). The invasion landing on the Kanto plains was Operation Coronet was called "Y-Day" and was scheduled for March 1, 1946. Olympic was to kick off with the largest single assembled naval fleet ever assembled, including 42 aircraft carriers, 24 battleships and nearly 400 destroyers. Okinawa, one of the islands my father helped to take, was to be used as the staging area and fourteen divisions were to be used in the initial landing.

You often hear of the Marines in the Pacific, but in reality, the U.S. Army was a strong presence, in many battles such as the invasion of the Philippines having more troops then the Marines. Olympic itself was to be spearheaded by the U.S. Sixth Army. There were 35 landing zones (each named for cars, Buick, Cadillac, etc.) and an entire corps was to land on each one of these zones. Estimates were that this would allow for three American troops to land for every one Japanese defender. While this seems like over-kill, historically, defending a position is much easier then taking one from your enemy. Also, Olympic wasn't supposed to capture the entirety of Kyushu, but rather just the southern portion of it. The idea was similar to the leapfrog idea from the island campaigns, capture only what was required to get to the next stage. The next stage was of course Operation Coronet, the invasion of the Kanto plains and into Tokyo.

The U.S. First Army was to land on the Boso Peninsula and the U.S. Eighth Army at Sagami Bay. Both armies, 25 divisions total, would drive north and link together at Tokyo. While tactically Coronet was much simpler then Olympic, casualty estimates was much greater. On paper it is all very simple. The plan was drawn up and the stage was set for the single greatest invasion in history. And then there was a flash of light.

On July 16, 1945, scientists at Trinity, New Mexico successfully tested an atomic bomb. It was decided immediately that this new weapon would be used on Japanese targets. On August 6, Colonel Paul Tibbets flew the B-29 Superfortress "Enola Gay" over Hiroshima and dropped the first atomic bomb to be used in combat. The bomb exploded with the force of 13 kilotons of TNT and an estimated 80,000 people were killed instantly. On August 9, Major Charles Sweeney flew the B-29 Superfortress "Bock's Car" over Nagasaki and dropped the second atomic bomb. An estimated 75,000 Japanese were killed instantly. With just two bombs 155,000 Japanese died. On August 15, 1945, the Japanese surrendered.

Many speculate that the atomic bomb's sheer power gave the Japanese leadership the ability to surrender and save face. Many believe that with an invasion, the Japanese would have been willing to fight to the bitter end. If those speculations are correct, then the tragic loss of those 155,000 Japanese at Hiroshima and Nagasaki actually saved an estimated 360,000 American lives and over an estimated half-million Japanese lives. Like the planned invasion, on paper it is all very simple. Though the atomic bombs may very well have brought the war to an end earlier with fewer casualties, it also paved the way for the Cold-War nuclear stand-off. Never again would militaries be able to go to war to win for fear of nuclear war breaking out. The next big war after WWII, the Korean War, ultimately led to a stale-mate. The UN could not wage all-out war for fear of a Soviet retaliation with nuclear weapons. The results were a stale-mate that exists to this day. In order to not be outdone, massive amounts of nuclear weapons were built, enough to destroy the world several times over. Some would say that it would have been better to not use the atomic bombs and that the Pandora's Box it opened just wasn't worth it. But then there are over 1.5 million American servicemen who should have been wounded or killed in Operation Downfall who would likely disagree with that and fully support the dropping of the atomic bombs. They are the lucky men of Operation Downfall, planned participants of the greatest invasion ever planned. My father was part of that plan. He was another number in the plan. On paper it is all very simple. In real life he would become a loving husband and father. In Japan, he was just another number, and except for that flash of light, he may have very well been a statistic.

Article © Van Lee. All rights reserved.
Published on 2005-08-08
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