With the surrender of Nazi Germany in May, 1945, the Allies turned their full attention to the Pacific theater. The U.S. began transferring troops from Europe.
The war in the Pacific, for the U.S., had been going on since the Japanese had attacked Pearl Harbor in late 1941, and longer than that for the British and French. Many great sea battles had been fought. Many losses had been endured by the Allied forces. The struggle had been painstakingly slow, fighting from island to island.
In the spring of 1945, the home islands of Japan herself remained to be taken to end the war. The invasion of Japan was planned for the spring of 1946. The planning of "Operation Downfall" (the actual invasion of the home islands of Japan) had been going on for some time. The early casualty estimates for the invasion were set at 130,000 to 220,000, of which the American death total was expected to be 25,000 to 46,000. However, after the battle for Okinawa, the U.S. realized the Japanese intended to fight to the death for the home islands, and the casualty figures were revised drastically.
2.3 million Japanese Soldiers were being set in place to defend the Japanese homeland. There were another 4 million Army and Navy employees which would be militarized. Finally, there were 28 million Japanese civilian militia, both men and women, who were preparing to die for their country. No surrender was contemplated.
The new casualty estimates for the invasion jumped to a more realistic 1.4 million to 4 million for the Allied invaders, up to 800,000 dead. As many as 20,000,000 Japanese casualties were predicted by the Imperial Japanese General staff, due to the entire population intending to fight to the death for their emperor. The allies put Japanese casualties at 5 to 10 million. Nobody really knew, of course. It was scary. Preposterous unfathomable numbers.
July 16, 1945, 0500.
Scientists and military men huddled in bunkers 10 miles distant from a metal tower with an odd-looking device, referred to only as "the gadget," hanging at the top of the tower.
0500:29: The New Mexico desert suddenly becomes as bright as noonday. Every rock and crevice of the nearby mountains is clearly visible. Even inside the distant bunkers, the heat is like an oven.
The military code name for the test of the device was "Trinity."
Dr. Robert Oppenheimer is one of the scientists in the bunker. As the odd mushroom cloud climbs higher and higher, a line from the Bhagavad Gita, a Hindu scripture, runs through his mind.
"Now I am become Death, the destroyer of worlds."
And so it came to pass that millions and millions of Japanese lives were spared; there was to be no invasion of the Japanese homeland by a slow and horrendous ground war. The Allied estimate of their own invasion casualties was revised downward from 4 million to zero.
In the end, out of great horror and still unspeakable death, came, for millions and millions, mercy of a sort.
But the genie is still out of the bottle.