American military archives reveal that if the Japanese had not surrendered on August 15, 1945, they would have been hit by a third and potentially more powerful atomic bomb just a few days later and then, eventually, an additional barrage of up to 12 further nuclear attacks.
Documents highlighted during commemorations to mark the 70th anniversary of the bombings of Hiroshima on August 6, and Nagasaki on August 9, which forced the end of World War II, show the determination of the United States to make Japan surrender unconditionally.
In the spring of 1945, the U.S. Army set up a special target committee to debate key Japanese cities to attack as officials believed their regime had already made it perfectly clear they were not willing to surrender at any price.
Confidential reports added that “even after two atom bombs, they preferred to fight on till they are all dead. Death or glory.”
If memory serves, it would have taken another 3-4 months to produce the 14 atomic bombs the White House and Army planned to drop on Japan following Hiroshima and Nagasaki. Kyoto was famously off limits because Secretary of War Henry Stimson was personally fond of the city. And there was no point to bombing Tokyo or other cities which had already been heavily firebombed — there just wasn’t much left to destroy in those places.
Meanwhile, planning was underway for MacArthur’s Operation Downfall invasion of the Home Islands — but that was doomed to be a bloodbath at best and a bloody stalemate at worst. Intelligence had vastly underestimated the number of kamikaze planes and suicide submarines Japan had prepared, in some cases by an order of magnitude. We had also no clue that Japan had correctly read MacArthur’s intention to initially invade at Kyūshū. That island had been turned into a giant Iwo Jima — a series of death traps manned by far more soldiers (and even civilians) than MacArthur had anticipated. Had Japan not surrendered, it could only be hoped that saner heads had prevailed and that Downfall had been postponed or cancelled.
The best targets then might have been infrastructure choke points to limit the distribution of rice and other foodstuffs from the countryside. Combined with the US Navy’s blockade of the Home Islands, that ought to have done the trick of starving Japan into submission over the course of a year or two. It’s impossible to say with any confidence exactly how many Japanese would have died, but the low end would have been in the millions and the high end in the tens of millions.
What a horrible way to end a horrible war. We can be thankful that Emperor Hirohito needed only two atomic bombings to see the light.