Operation Downfall
The main concern for the Americans was the potential for huge casualty rates. Nearly every senior officer involved in the planning did his own research regarding American casualties – this was based on the experience America had fighting the Japanese since
Pearl Harbour.
The Joint Chiefs of Staff estimated that
Olympic alone would cost 456,000 men, including 109,000 killed. Including
Coronet, it was estimated that America would experience 1.2 million casualties, with 267,000 deaths.
Staff working for
Chester Nimitz, calculated that the first 30 days of Olympic alone would cost 49,000 men.
MacArthur’s staff concluded that America would suffer 125,000 casualties after 120 days, a figure that was later reduced to 105,000 casualties after his staff subtracted the men who when wounded could return to battle.
General Marshall, in conference with
President Truman, estimated 31,000 in 30 days after landing in Kyushu. Admiral Leahy estimated that the invasion would cost 268,000 casualties. Personnel at the Navy Department estimated that the total losses to America would be between 1.7 and 4 million with 400,000 to 800,000 deaths. The same department estimated that there would be up to 10 million Japanese casualties. The ‘Los Angeles Times’ estimated that America would suffer up to 1 million casualties.
Regardless of which figures were used, it was an accepted fact that America would lose a very large number of men. This was one of the reasons why
President Truman authorised the use of the
atomic bomb in an effort to get Japan to surrender. On August 6th, ‘Little Boy’ was dropped on
Hiroshima and on August 9th, ‘Fat Man’ was dropped on
Nagasaki. On September 2nd, Japan surrendered and America and her allies were spared the task of invading Japan with the projected massive casualties this would entail.