What was "Operation Downfall"?

Operation Downfall was the military code name for the Allied plan for the invasion of Japan, when World War II was coming nearer to its end. The operation was going to become the largest and greatest amphibious assault in military history, but it never took place.

The planned operation was abandoned when Japan surrendered following the atomic bombings of Hiroshima and Nagasaki. Downfall consisted of 2 steps: Operation Olympic and Operation Coronet. The first one, which was set to begin in 1945, was intended to capture the southern third of the southernmost main Japanese island, Kyūshū. Operation Coronet, which was to take place in 1946, would be the invasion of the Kantō Plain. Actually, the plan of invasion was quite obvious for the Japanese, as the geography of the country wouldn't let the anti-German coalition act any other way. As the operation never happened, D-Day (or the operation Neptune, which took place on the 6th of June, 1944) remained (and still remains) the largest operation of a kind of all time.

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16 Comments

Rob Blomquist

D-Day was the largest amphibious landing operation of all time but it was by no means the largest military operation of all time - The Battle of Kursk in the Soviet Union in 1943 was much larger on both the Soviet and German sides and involed months of preparation and involved over a million troops on both sides.

Raashid Khan

Wars for whatever come with devastation and sufferings.Hate wars

John W Shreve

Raashid Khan, Theodore Roosevelt called the Spanish-American War a "Dandy little war."

John W Shreve

James Webb, There is a series of books titled "What if?" that covers those sorts of things.

Fred Keogh

Keith Richard Mears, the actual code name was 'Downfall', and consisted of 2 parts. Operation Olympic, the invasion Kyushu and Operation Coronet, the invasion of Honshu. Kyushu and Honshu being the 2 main islands of Japan.

Fred Keogh

Carroll Price, I would be very pleased if you could tell me what negotiations for Japanese Surrender were taking place. I have studied WW2 for many years and have not found any reference to a set of negotiations for this surrender. Any inference of surrender was quickly suppressed by the Japanese military, who retained their warlike stance to the very end.

Keith Richard Mears

I always thought that the operation which would have seen an invasion of the Japanese homeland, was called operation coronet.

Ken Putnam

Fran Graybowski, Try millions As well.as the complete destruction of the Home Islands

Ken Putnam

Darlene Davidson, Rrally? They saved millions of lives o both sides, as well.as the complete destruction of the Japanese home islands

Richard D. Boyle

“Downfall”, if executed, would have resulted in a replay of the bloodbath of Iwo Jima and Okinawa times 10, times 100, times 1000...? We will never know thankfully.

Ian Swindale

The overall plan for the invasion of Europe on D-Day was Operation Overlord - Neptune was only part of it - see Antony Beevor's book entitled simply "D-Day"