Japan post-Olympic

I've searched, but haven't found anything relevant. So, let's suppose that the Manhattan Project can't produce a workable fission bomb by the time Olympic concludes. What would likely happen to Japan? Other than "nothing good." I already know that much.
 
All POWs held by Japan are almost certain to be executed, probably before the invasion starts in earnest. The US blockade/mining/submarine campaign is going to make an awful lot of Japanese starve as well.
 
It would be Hell on Earth, Barbarossa would be the only thing to compare it to. The actual plan B however as I understand it would be blockade and famine, which would also be horrific but at least would spare US casualties.
 
Blockade plus possible use of Anthrax on arable land and gas on cities. Have seen estimates of 100 million dead.

Japan only had about 72 million people in it in 1945. Where are the other 28 million coming from?

Torqumada
 
I believe it was Calbear's TL that put it perfectly, with a comment to the effect that in early 46 Japan lays down and dies.

Op Starvation is the reasonable assumption. If we use comparable famines as a guide, yes, we're talking 10s of millions of deaths. Add anthrax and gas, and we're talking mountains of skulls territory...

Downfall would be even worse. Without atomics, gas will be used by the US starting with Olympic. Unless you have an unusual POD, the US will have atomic bombs available shortly after Olympic, and will likely be used for Coronet. With gas already in use, and the probable Japanese retaliation (sporadic and local - they won't be capable of a seriously threatening gas attack, there will be a looser hand with the atomics and gas.

And lets not forget that the Soviets are planning to hit Hokkaido in late August.
 

CalBear

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No Bomb doesn't automatically equal Olympic.

What is very likely is that Olympic is delayed due to the October 1945 Typhoon that smacked Okinawa, including the assembly area for about 1/4 of the total invasion force, the airbases that were going to provide a decent amount of the counter-air and CAS, and the warehouses (some 80% of the structures put up by the U.S. military specifically to support the operation were destroyed).

That delays things by 4-6 weeks, taking it to mid December. At that time the flying hours are very low (about 5 hours of sunlight, on average, once normal weather in the area is factored in) so you may see a delay at that time as well, into the Spring.

IOTL, by the second week of August about the only big supporter of the operation was, unsurprising, MacArthur. Everyone else was increasingly spooked by the Intel that showed ever more IJA troops and more & more kamikaze aircraft entering the invasion zone. It is very likely that the U.S. just doubles down on the blockade, including a strong presence off Hokkaido and heavy mining there by B-29s (to prevent any IJA elements from escaping to the Home Islands of course) and, once the 8th AF is stood up with its reequipped squadrons of B-29s operating out of both Okinawa and Tinian kicks the firebombing campaign into a seven days a week operation while mediums and fighter bombers (both land based and off carriers) attack the transport network and targets of opportunity (meaning anything with wheels down to an ox-cart). Strong chance that the Japanese surrender as soon as starvation starts really killing folks in numbers, probably before March 1.

Down side of this is that ALL the PoW in Japan will be dead by that time, 6-700,000 civilians in the IJA occupied regions of China and elsewhere will be dead as well (it was running, by most estimates, at around 90-100,000 dead civilians a month at summer of 1945), and probably 350-450,000 Japanese civilians from the combination of bombing and starvation (which will kill more, the fires or the famine is an open question). So, the delay adds around 1-1.1 million civilian deaths, plus the follow on damage to the Japanese population due to the mass starvation, especially of younger children, elderly, and women (who the IJA more or less had decided didn't deserve to eat by July, based on ration levels).

IF Olympic does come off as scheduled, with the full force size the next step is Coronet, the landings near Tokyo. Unbeknownst to the Americans the Japanese were prepared to shoot their bolt on Kyushu, virtually all their aircraft, ships, and fuel were going to be used to bleed the Allies into negotiating a "just end to the war" (i.e. No war crimes trials, no occupation, no change in government, not just the Emperor, but the rest of the systems as well, etc.). If that didn't happen the IJA/IJN would have almost no serious firepower for Honshu. No kamikazes, no suicide boats, very little fuel for their armor, not even much in the way of transport. Landing would have been near the Tokyo/Yokohama with 15 divisions, including two FULL armored divisions, with six more divisions scheduled to reinforce on D+35, with an airborne division and a floating reserve of 3 more divisions available on D+40. It was expected that the capture of the Kanto Plain would force the Japanese to surrender unconditionally. If that failed to occur there would be further reinforcement, both by U.S. units and units from the WAllies, including Australian, British, Canadian and French divisions.

Interestingly, unlike on Kyushu, where the IJA determined exactly which locations were the likely U.S. landing points and planned their defenses almost as if they had a crystal ball, they totally missed on Honshu. Their battle plan called for stopping the invaders at the water's edge and forcing a virtual hand to hand engagement to negate the American advantage if air and naval firepower. The greatest effort was to be at Kujukuri-hama on the Boso Peninsula, it was to be the prime defensive effort, with priority for all reinforcements, and was where the IJA was going to deply both of its remaining armored divisions. The Americans planned to land there with 1st Army, but with only about 40% of the landing force. The main effort, by the U.S. 8th Army was to land at Sagami Bay (which the Japanese had identified as a probably landing site, but had given a much lower priority). If the engagement had happened as the IJA planned around 2/3 of its Kanto Plain foces would have been trapped on the Boso Peninsula, cut off from the rest of the IJA effort by Tokyo Bay and with a 100+ mile march, across some pretty rough country while under more or less constant air and naval gunfire attack. If the Americans had planned it the Japanese deployments could not have been more in 8th Army's favor.

By the time it was done (assuming the Japanese don't decide to fight to the last cartridge, which is a fairly major assumption), U.S. losses would probably be in the 150-200,000 KIA, x3 wounded area or around 600-800,000 total KIA/WIA/MIA. IJA losses, 90%+ KIA, would be around 1.25-1.75 million (depending on when they finally gave up on the Boso Peninsula, and stopped feeding men into the grinder as soon as then arrived, which, BTW, WAS the actual battle plan). Figure and easy 2.5 million "militia" total casualties, probably 60% KIA, and another 500K-1M civilians who simply get caught in the way. All told, 200K U.S. and 3-4.5 MILLION Japanese, dead, just on Honshu. Between the two operations, 350-400,000 U.S. KIA and upward of 7 million Japanese, along the 700,000 plus civilians who die on the Asian mainland (not counting casualties from the Red Army's advance across all of Manchuria and the Korean Peninsula).
 
Between November when Olympic would happen and April/May when Coronet would happen there will be widespread starvation in Japan. There will be essentially zero imports, and the rice harvest was going to bad (it was OTL) and with the extra bombing and destruction of the transportation systems by fighter bombers and light/medium bombers out of Kyushu and carrier aircraft, it would be horrendous. There would be nothing moving by day, no RRs and any coastal traffic by ship minimal. Even fishing boats would be toast, making the food situation even worse. Of course, what food there was would be for the military.

If Coronet had to go forward (invasion of Honshu/Kanto Plain) even worse. Since the plan was for civilians including women and and children to fight even with spears, the slaughter would be terrible. The end result would be a Japan even more devastated physically than OTL with the number of dead from starvation and fighting waaaay more than died in Hirsohima and Nagasaki. Depending on when Japan surrendered the USSR might or might not invade Hokkaido depending on the dates...Soviet capability to do that was limited.
 
Between the two operations, 350-400,000 U.S. KIA and upward of 7 million Japanese, along the 700,000 plus civilians who die on the Asian mainland (not counting casualties from the Red Army's advance across all of Manchuria and the Korean Peninsula).
Plus, of course, the ongoing famine after whatever kind of end to the war comes along. With that many starving mouths, the US isn't going to be able to feed them all. If BW/CW agents have been used, that will add to the death toll.

The Japanese home islands may well have holdouts, similar to a number of Pacific islands. Probably not too many, but the ones that survive after the US has hunted down and pacified any villages that have tried to continue the war will be quite tough.

Worst case, I could even imagine a hard core of IJA personnel fighting an ongoing guerilla campaign against the US occupation forces. Suicide bombers would of course fit quite nicely with the Japanese ethos. The US might just find itself fighting a nasty counterinsurgency campaign after the official end of the war.
 
Never read of a proposed anthrax usage.

The british had discovered Tabun stockpiles and were planning to transport them to the Pacific for use on Japan.

The americans had developed a very potent defoliant 2,4-D which would have wrecked disaster on rice paddies and, later on, hill/mountain areas. While 2,4-D is not a healthy products, I have read that often it is contaminated by dioxin, so a widespread 2,4-D campain could inflict long term contamination to the territory.

Last, don't forget the final banzai charge/mass suicide.
 
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