Operation Downfall was a planned land invasion of Japan by the allies using the combined strength of the army, navy and air forces. The operation was first developed in early 1945 by chiefs of staff at the Argonaut Conference. This conference ended in the following proposed objectives:
- The seizure of additional positions in order to strengthen the blockade air bombardment of Japan
- An assault on Kyushu which would reduce Japanese abilities by containing and destroying enemy forces as well as strengthening the blockade
- A decisive invasion of the industrial heart of Japan
On March 29, 1945, the US joint Chiefs Of Staff set a tentative schedule for the operation, working off the assumption that the war in Europe would conclude at the beginning of July 1945. Operation Downfall was split into two phases: “Olympic” and “Coronet”.
Operation Olympic consisted of an assault on Kyushu, and its main purpose was to use the land acquired in the invasion for air bases that were necessary for the next part of the operation (operation Coronet). Operation Olympic was originally set for December 1st, 1945 but was later moved to a month earlier, November 1st. Only a small area of the southern part of the island was needed for the airbases (3,000 square miles would have been sufficient) and an estimate of 42 aircraft carriers, 24 battleships, 400 destroyers, and destroyer escorts would have been needed in this operation.
The second phase of the operation, Operation Coronet, involved landing on Honshu and targeting the Tokyo area. The goal was to eventually occupy the Tokyo-Yokohama area. The operation would have needed the support of the army and navy in the Pacific as well as units redeployed from Europe. It was scheduled for March 1st, 1946.
The Japanese also had a plan to combat the suspected land invasion by the allies. This plan was entitled Operation Ketsugō. Japanese leaders did not believe in any way that they could win the war, however, they believed that they could make the cost of invading and occupying to high for allies to accept, resulting in an armistice rather than a total defeat. The operation included the commitment of the entire population of Japan in resisting the invasion. This is evident in the Propaganda campaign “The Glorious Death of One Hundred Million”. This stated that is was “glorious” to die for the holy emperor and that all Japanese citizens (men, women, and children) should be willing to die for the Emperor when the Allies arrived. The propaganda also depicted Americans as white devils, inhuman and demonic enemies.
The main concern for Americans about Operation Downfall was the huge estimated casualties. The Joint Chiefs of Staff estimated that Operation Olympic (the first phase of the operation) would result in the casualties of 456,000 men with 109,000 deaths. Including the second phase of the operation (Operation Coronet) there was an estimate of 1.2 million casualties, with 267,000 deaths.
This was one of the reasons that President Truman chose to authorize the use of the atomic bomb as a means to get Japan to surrender instead Japan surrendered on September 2nd so Operation Downfall never came to Fruition, though many hypothesize what would have happened if it had.
Sources
https://www.historylearningsite.co.uk/world-war-two/the-pacific-war-1941-to-1945/operation-downfall/
https://history.army.mil/books/wwii/MacArthur%20Reports/MacArthur%20V1/ch13.htm
Your post was very informative and well written! I researched Truman's decision a bit further and found that he actually had four options: (1) continue conventional bombing of Japanese cities (2) invade Japan (3) demonstrate the atomic bomb on an unpopulated island or (4) drop the atomic bomb on an inhabited Japanese city. Truman noticed that conventional bombing was not effective because it wasn't enough to get Japan to surrender. As you said in your post, Truman decided not to invade Japan because it would result in too many American casualties. Demonstrating the atomic bomb on an unpopulated island was ruled out based on multiple concerns: Truman wondered if only a small group of people would evaluate the destruction, and they probably didn't have enough power to decide whether or not a whole nation should surrender. Furthermore, the atomic bomb was a new weapon at the time, so it would be embarrassing if it didn't work. In the end, Truman and his committee decided to bomb a Japanese city because it was the only option they believed would leave a big enough impression that would force Japan to surrender.
ReplyDeleteSource: https://www.nps.gov/articles/trumanatomicbomb.htm