What if Japan hadn't surrendered?

If Japan had refused to surrender and forced the invasion of the home islands what would have happened? I have a feeling that as fanatical as they were about fighting to the last man and the fact that civilians were committing suicide rather than be captured there would be almost no Japanese left at the end of the war.

There would have been an invasion of the home islands.

We were out of nukes after Hiroshima and Nagasaki, and AIUI it would have taken quite a while to produce enough fissile material for more bombs. In the absence of that - and even before that - firebombing was comparably effective. One firebombing attack required more aircraft than a nuke attack, but you could manufacture incendiary bombs much more easily and quickly than nukes. And if the incendiary payload ends up burning down more buildings than the same quantity of explosive bombs would have, then ISTM that firebombing delivers more bang for your buck, so to speak, than precision bombing with high explosives.

The firebombing attacks on Japanese cities continued up until the end of the war, and surely would have continued after Hiroshima and Nagasaki if Japan had refused to surrender. With American production capacity perfectly intact, we could have continued manufacturing and delivering massive quantities of incendiary bombs for another couple of years, shredding Japan’s industrial capacity until they would not have been able to even make bullets for rifles, let alone bombs/planes/ships. A home-island invasion need not have happened until after that point, minimizing US casualties (but sending the Japanese body count sky-high).

It’s possible that other alternatives would be:

  1. Nuking and/or conventional bombing of Japan, for years or even decades to come (the USA could just do it leisurely)

  2. Blockade, again for years or decades to come
    Both of those options would be more attractive to the US than outright invasion. But if Operation Downfall had gone forward as you postulate, yes, it’s possible the Japanese would fight until the majority or even vast majority would be dead. They had a mantra:* Ichioku gyokusai*, (“one hundred million shattered jades,” figurative meaning “the hundred million Japanese die together rather than surrender.”)

It is even possible that Operation Downfall would have failed. Pulling off the largest amphibious invasion in history is no gimme, and the Japanese were more fanatical (although perhaps not as well armed) as the Germans at Normandy. But if Downfall had failed, the USA would have probably just gone back to blockade and/or bombing as the secondary options.

Estimates of casualties resulting from an invasion of Japan were, IIRC, a half-million Allied and a million Japanese.

The point of the atomic bombings was to make it clear that the kamikaze tactic was no longer operative. The Japanese were going to die, but they weren’t going to be able to take any of the enemy with them.

It may have taken a few months to create and deliver another bomb. But the message was “so far you lost Hiroshima and Nagasaki without a single shot being fired in return. Next up is Tokyo, and you are not going to die heroically - you are just going to die, period. So will your emperor, so will your ancient cities. And there ain’t a damn thing you can do about it.”


(my bolding) No, we weren’t. Cite, conversation between General Hull & Colonel Seaman explaining exactly how many more atomic bombs were available. One ready to go immediately (though it would take about 2 weeks to deliver it to a location it could be dropped from), 3 or 4 in September, probably 3 in October, then 3 a month after that. Every single one of them would have been used if the invasion had occurred. Japan would probably still be a USA protectorate at this point.

Thanks, muldoonthief. I was about to hunt for citations.

How much more damage would bombing have caused? Large chunks of Japan were already in ruins. I’ve read that the reason that Hiroshima and Nagasaki were chosen for the nukes was because they were about the last major cities that were relatively undamaged.

I would imagine that the Soviet Union would have been far more involved in the pacific theatre than they ended up being in real life. That would have had political and economic repercussions, perhaps included a divided-up Japan akin to the divided Germany.

It appears that Stalin was eager to participate in the invasion of Japan and to fight in Manchria.

Supposedly, the land on which the Pentagon sits was acquired to build hospitals to treat Allied wounded in the invasion. Also, supposedly, we are still using Purple Heart medals struck in anticipation of the casualties of the invasion.

There’s a school of thought that subscribes to the notion that the timing of Japan’s surrender had much more to do with the USSR’s entry into the war than dropping two atom bombs. Bear in mind we’d been leveling their cities in bombing raids for many months without capitulation. That the bombs happened not to be conventional was arguably incidental.

The invasion of Japan? Construction of the Pentagon began on Sep 11, 1941, 3 months before the attack on Pearl Harbor.

The preparations for the invasion, and for the defense, of Imperial Japan were well under way. Both sides were preparing for a very long, and bloody, fight. The sudden, and unexpected, introduction of working models of atomic weapons changed everyone’s plans.

Operation Downfall consisted of two huge beach landings on the Japanese mainland. Operation Olympic was larger than the D-day landing on Normandy, and Operation Coronet was several times larger than Olympic. Imperial Japan prepared for an Allied invasion force that was twice as large as what was actually planned. Kamikaze planes, ships, and submarines would have wreaked havoc on the landing forces. Cities, ports, farming, and industry would have been devastated. Millions would have died during the invasion. Millions more on the island would have died from wounds, exposure, starvation, and disease after Imperial Japan had finally surrendered.

*Operation Olympic, the invasion of Kyūshū, was to begin on “X-Day”, which was scheduled for 1 November 1945. The combined Allied naval armada would have been the largest ever assembled, including 42 aircraft carriers, 24 battleships, and 400 destroyers and destroyer escorts. Fourteen US “division-equivalents” (13 divisions and two regimental combat teams)[27] were scheduled to take part in the initial landings. Using Okinawa as a staging base, the objective would have been to seize the southern portion of Kyūshū. This area would then be used as a further staging point to attack Honshu in Operation Coronet.

…Operation Coronet, the invasion of Honshu at the Kantō Plain south of the capital, was to begin on “Y-Day”, which was tentatively scheduled for 1 March 1946.[32] Coronet would have been even larger than Olympic, with up to 40 divisions earmarked for both the initial landing and follow-up.[33] (The Overlord invasion of Normandy, by comparison, deployed 12 divisions in the initial landings.) In the initial stage, the First Army would have invaded at Kujūkuri Beach, on the Bōsō Peninsula, while Eighth Army invaded at Hiratsuka, on Sagami Bay.[34] Later, a follow-up force of up to 12 additional divisions of the Tenth Army and British Commonwealth Corps would be landed as reinforcements.[35] The Allied forces would then have driven north and inland, meeting at Tokyo.

…Meanwhile, the Japanese had their own plans. Initially, they were concerned about an invasion during the summer of 1945. However, the Battle of Okinawa went on for so long that they concluded the Allies would not be able to launch another operation before the typhoon season, during which the weather would be too risky for amphibious operations. Japanese intelligence predicted fairly closely where the invasion would take place: southern Kyūshū at Miyazaki, Ariake Bay, and/or the Satsuma Peninsula.[45]

While Japan no longer had a realistic prospect of winning the war, Japan’s leaders believed they could make the cost of conquering Japan too high for the Allies to accept, which would lead to some sort of armistice rather than total defeat. The Japanese plan for defeating the invasion was called Operation Ketsugō (決号作戦 ketsugō sakusen?) (“Operation Codename Decisive”). The Japanese were secretly constructing an underground headquarters in Matsushiro, Nagano Prefecture, which could be used in the event of Allied invasion to shelter the Emperor and the Imperial General Staff. It is worth noting that in planning for Operation Ketsugo, IGHQ vastly overestimated the strength of the Allied forces they would be facing: while the actual Allied invasion plan called for as many as 54 divisions (14 for Olympic and 38-40 for Coronet), the Japanese expected up to 90.[33]*

Ignorance fought, thanks.

Why was the USSR not mentioned in his surrender speech?

Stalin was aware of the U.S.A.'s progress to build a working nuclear weapon. Stalin also wanted his share of post-war Imperial Japan’s land and treasure. Stalin declared war on Imperial Japan the day after the U.S. proved to the world that they had a working nuclear weapon. Coincidence? Personally, I doubt it.

Imperial Japan did not know how many working nuclear weapons the U.S. had in it’s arsenal. More bombs could be dropped at any time. Or the Allies could be waiting to see how the Imperial military reacted. As it was, it took six days after the destruction of Nagasaki before Imperial Japan surrendered.

It’s very doubtful. It’s the same school of thought that sez that since the USSR lost the most me, it won the war all by itself, and didnt need any help-.

Which is contrary to what Stalin himself said. He said they would have lost without Lend Lease and without the Second front.

We have the notes and stuff from the Japanese leadership, and the Bomb gave them a honorable way out, one that the USSR attacking didnt. In other words, they capitulated to superior technology, not better soldiers.

Russia had agreed to declare war on Japan after victory in Europe at the Yalta conference.
Truman realized at the end of the war in Europe that Russia would try to claim territory in Manchuria and Japan. He wanted very badly to prevent this. In Europe, the Russians claimed that countries that had “liberated” from the Nazis belonged to Russia.

Would you surrender and give Stalin an excuse to share the spoils? There is a reason that many in Germany preferred surrendering to the Americans and British rather than to Russia.

Stalin agreed at Yalta in February 1945 that the Soviet Union would enter the fight against Japan “in two or three months after Germany has surrendered and the war in Europe is terminated.”

VE-Day was May 8, 1945. The Soviets kept this agreement by entering the fight August 9, 1945 exactly 3 months to the day.