The Planned Invasion of Japan, Ww2

The American military commanders that were given the task of planning the invasion were: Douglas MacArthur, Chester Nimitz, Ernest King, William Leahy, Hap Arnold, and George Marshall. Eventually, because of army-navy rivalry, the navy agreed that U.S. Army Senior Military Officer Douglas MacArthur should have total control of the planning. The planning was assisted by Commander-in-Chief of the Pacific fleet, Chester Nimitz. Operation Downfall had to be complete within one year of the surrender of Germany to keep the moral of the soldiers from dropping to far. So, Operation Downfall was itself divided into two parts: Operation Olympic and Operation Coronet.

 The first section of Operation Downfall was Operation Olympic. Operation Olympic was set to start on X-day, or November 1, 1945. The objective of this operation was to capture the southern third of the island of Kyushu. The naval armada participating in the invasion would have been the largest ever assembled in history, until Operation Coronet would take place a few months later. The invasion force consisted of forty-two aircraft carriers, twenty-four battleships, 400 destroyers and destroyer escorts, and the Sixth Army, which consisted of an initial 14 divisions of troops. All of the thirty-five landing beaches were named after automobiles. The casualty ratings would have been close to 450,000 deaths and 100,000 injured or missing.

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Before the main landings took place the offshore islands of Tanegashima, Yakushima, and Koshikijima had to be taken. The landings would have taken place at three different points   Ariake, Miyazaki, and Kushicino. At 4 o’clock on X-day the first landing of the day would have been at Miyazaki. Miyazaki is first to be landed on because the Japanese would have left it virtually undefended. Next an hour later, at 5 o’clock, the invasion of Ariake would have commenced. Ariake was to most heavily defended spot. It had a strategic harbor and had a dense population of enemy troops. Lastly at 7 o’clock the Allied troop would have been landing on the shores of Kushicino. Kushicino was not very heavily defended but the type of terrain surrounding the landing points would have made it the hardest of the three to capture. The campaign would have last over the next 90 days until December 1946. Then, airfields would have been build to support efforts of Operation Coronet.

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Like most major landings in history Operation Olympic had a deception plan. It was known as Operation Pastel. It was designed to convince the Japanese that the Allies were going to surround Japan and bombard it from all sides. To deceive the Japanese into thinking this, bases in Formosa, the Yellow Sea, and along the coast of China were captured. Operation Coronet was the following phase of Operation Downfall. It was set to start on December 1, 1945, but was pushed back to March 1, 1946 to wait until Operation Olympic was over. This happened because in order for Operation Coronet to work, Operation Olympic had to be a success.  All of these details are finely intertwined, so If one stage failed, it all would fail. This, other that the atomic bombs, was a key reason why this Operation was scrapped.