Operation Downfall

Operation Downfall was the proposed invasion of mainland Japan by

Allied Forces near the end of WWII.  It was canceled because the atomic

bombs were dropped and Japan surrendered, thereby removing the need for

a military conquest.  It would have been the largest amphibious

invasion in history, and it would have been the first time that a

foreign power had set foot on mainland Japanese soil (in the country's

2500 year history). 

Operation Downfall had two parts: Operation Olympic (Nov 1945) and

Operation Coronet (March 1946).  Both were commanded by MacArthur and

supported by Nimitz.  Operation Olympic involved the I, V, IX, and XI

Corps storming the beaches of Kyushu (the southern main island) and

taking airbases to support Operation Coronet.  Operation Coronet

involved the First Army and the Eighth Army, as well as numerous

British Commonwealth units, storming the beaches of Honshu near the

capital city of Tokyo. 

On the opposing side was Operation Ketsu Go, the Japanese defense of

its main islands.  Most of Japan's forces (air and ground) were focused

on the island of Kyushu.  Also, tens of millions of Japanese civilians

(all able-bodied civilians, men and women) were trained in basic

martial arts in order to repel the invasion.  In addition, the Japanese

government created numerous suicide units to repel the invasion. 

All in all, it would have been one of the bloodiest battles in

history.  An estimated 1 million Americans and 10 million Japanese

would have lost their lives. 

For more information, read:

The Japanese Army Handbook by George Forty

The Pacific War Companion by Daniel Marston

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