Operation Downfall, Part I

Last updated on June 29, 2022

As 1944 turned into 1945 an Allied victory in the Pacific was creeping closer to reality. Little by little American forces were rolling up the Japanese defenses one island at a time as they pushed the invaders back further and further towards the Japanese mainland. Guam had been taken, the Philippines were being contained and bombing on Iwo Jima was underway. In this atmosphere of cautious optimism the ideas for Operation Downfall, as it would be called, were being hashed out by the Combined Chiefs of Staff at the Argonaut Conference ¹The codename for The Yalta Conference, the 1945 wartime meeting between Franklin D. Roosevelt, Winston Churchill, and Joseph Stalin held on the tiny island of Malta in the Mediterranean. The conference called for the defeat of Japan within eighteen months of the surrender of Germany, and this would entail a possible amphibious landing on the Japanese mainland itself. At the time the Manhattan Project was a closely guarded secret so the members at the conference didn’t even take its existence into account.

The conference had many other factors to think about also. How could they force an unconditional Japanese surrender with the least amount of Allied casualties in the shortest period of time? Originally a joint British-American team had written a document entitled “Appreciation and Plan for the Defeat of Japan” where they didn’t foresee an invasion until after 1947 but the conference felt that dragging the war out that far would have dangerous consequences to American morale at home. And not only would the Allies face Japanese military units but also a “fanatically hostile population”. Fighting the Japanese military was one thing, facing an entire population armed with various weapons carrying out banzai attacks was another. The death toll on both sides could have been tremendous.

In light of this the US Navy urged a sea blockade and airpower to bring about surrender. The US Army Air Force, using captured airbases in China and Korea would be able to bombard Japan into submission.²A sea blockade had helped the US defeat another enemy roughly 80 years previous to this – The Confederate States of America. The US Army, though, believed that the strategy could prolong the war for an indeterminate amount of time and needlessly waste lives. In light of this the Army’s opinion won out.

And so planning on the two-part invasion began. It was to be broken into two operations, Olympic and Coronet with Olympic scheduled to begin on X-Day – November 1, 1945.³Info for this post came from both Military History Encyclopedia on the Web and Wikipedia.

We’ll talk about the first phase, Olympic, next time.