WI Olympic but no Coronet?

[oudi14]

The reason for this is that the development of the bomb is six months behind where it was on our TL, for whatever reason. The first detonation takes place at the Trinity test site, on Jan. 16th, 1946.

So, in the late summer of 1945, plans for Operation Downfall continue as scheduled. [And for those of you who believe the Japanese military could have not stayed in the fight until November, please, please, just this once, assume they would be too stubborn to give it up] And, as was expected, on November 1st, 1945, Allied forces launched Operation Olympic, and began landing on beaches on the southern end of the Japanese island of Kyushu, amid fierce resistance. After a number of weeks, they meet their objectives, after suffering awful casualties; [like Iwo, only on a larger scale] with Japanese military and civilian losses sometimes approaching the unbelievable.

Early in the new year, as Macarthur and his staff prepare for phase 2, Operation Coronet, due to begin on March 1st; they privately wonder how the forces at their disposal can handle another round of catastrophic losses. Then,on February 6th, comes news that a plane named Enola Gay dropped a bomb named Little Boy on the city of Hiroshima. When the bomb exploded, a great white light appeared over the Japanese islands, the likes of which the world had never seen before.

So now what? A second bomb, as in OTL? Or is everyone so exhausted, that this event pushes the Emperor into accepting unconditional surrender? What have the Soviets been doing all this time? Do they still declare war on August 8th, and invade Hokkhaido in the fall of 1945? How is the American public affected by the continuation of the war?

[BTW, this almost certainly will butterfly away the sinking of the Indianapolis, as she will be somplace else on July 30]

 

[Matt Wiser]

Good question. OLYMPIC would certainly have gone ahead had the bombs not been available, at a high cost-similar to that of Normandy (which had 63,000 casualties from D-Day to D+48) Japanse casualties would exceed 200,000 in Kyushu...

The original orders for using the bombs gave release authority to 21st Bomber Command (code name: CENTERBOARD for the nuclear strikes). So the 509th keeps dropping unless they get an order to stop. So TTL the second strike goes ahead under those circumstances. Depending on weather, Kokura is struck instead of Nagasaki's place. (it was the secondary target on 6 Aug 45, and the primary on 9 Aug)

 

[MerryPrankster]

Interesting scenario.

Might the bombs be used in a more tactical role if there's a land war in the Home Islands, like taking out an entire army's supply lines all at once?

 

[Matt Wiser]

Tactical use was under preliminary consideration. Marshall was interested, and asked both Groves and Oppenheimer if the Fat Man bomb could be used in a tactical role. But no firm decision had been made prior to the actual surrender.

 

[Ariosto]

An idea that kept popping into my head regarding Olympic was the initial wave being sent forward and utterly blunted; there were only going to be a couple hospital ships as I recall, and even if half of those were hit (not sunk, hit) and there was significant damage to the blood supplies, many men would die on the beaches from not receiving transfusions when needed, among other things.

After the disaster of the first wave, the Americans withdraw with much of the Japanese military on the beach line cheering at their victory. Shortly after a couple of B-29's come over the beaches and drop their loads..............

 

[DuQuense]

What have the Soviets been doing all this time? Do they still declare war on August 8th, and invade Hokkhaido in the fall of 1945? How is the American public affected by the continuation of the war?

While the DoW in August was agreed on long before V-E Day at the Tehran Conference, The Allies made it clear in 1945 that the Home Island were the Allies Responsibility.
There would have been no Russian invasion of Hokkaido.

Probably the Russians continue south of the Wall and attack the Japanese in China.

Meanwhile the Allies Invade Indonesia, and Indochina.

 

[Ariosto]

While the DoW in August was agreed on long before V-E Day at the Tehran Conference, The Allies made it clear in 1945 that the Home Island were the Allies Responsibility.
There would have been no Russian invasion of Hokkaido.

Probably the Russians continue south of the Wall and attack the Japanese in China.

Meanwhile the Allies Invade Indonesia, and Indochina.

Well, the preparations were certainly there, and they would have been able to land a number of divisions upon Hokkaido which would have met weak resistance due to most of the Japanese forces having been diverted South. This was already planned to occur by the end of August, so they either did not seriously consider Allied threats on entering this exclusive zone of responsibility, or they simply didn't care.

 

[Matt Wiser]

Each Corps (I Corps at Miyazaki, XI Corps at Ariake Bay, and V Marine Amphibious Corps at Kushikino) had enough forces coming ashore on X-Day to get established. The U.S. had never been forced off a beach during the entire Pacific War, and there was ample firepower both offshore and in the air to ensure the beachheads get established. Six battleships and eight heavy cruisers at Ariake, four battleships and six heavies at Miyazaki, and three battleships and eight heavies at Kushikino....lots of metal being thrown in the air. And ample air support from both carriers and the Ryukyus.

 

[phil5775]

No Coronet needed after Olympic. With the Americans in control of Kyushu, despite a lengthy and bloody battle, the shock of an invader capturing and occupying one of their Home Islands would have proven to be a greater shock to the Japanese than the bomb. Hirohito would surely have had the foresight to see the loss of his people (both military and civilian) killed in Olympic would be even greater in a subsequent invasion, and therefore takes the necessary steps to end the war.

 

[usertron2020]

Well, the preparations were certainly there, and they would have been able to land a number of divisions upon Hokkaido which would have met weak resistance due to most of the Japanese forces having been diverted South. This was already planned to occur by the end of August, so they either did not seriously consider Allied threats on entering this exclusive zone of responsibility, or they simply didn't care.

It was on another thread someone noted that Stalin's admirals told him that an invasion of Hokkaido would have to be delayed until the Spring of 1946, due to the paucity of Soviet naval assets in the Pacific. Considering that the Soviets were nearly driven into the sea at Paramushiro (in the Kuriles) before the Japanese garrison was ordered to cease resistance, I'd say the admiral were right.

The forces in Hokkaido were weak, but after a Soviet DoW I can't see the IJA failing to reinforce the island. Naval interdiction wasn't exactly a Soviet specialty. And Hokkaido is a logistical nightmare for any invader.

 

[usertron2020]

No Coronet needed after Olympic. With the Americans in control of Kyushu, despite a lengthy and bloody battle, the shock of an invader capturing and occupying one of their Home Islands would have proven to be a greater shock to the Japanese than the bomb. Hirohito would surely have had the foresight to see the loss of his people (both military and civilian) killed in Olympic would be even greater in a subsequent invasion, and therefore takes the necessary steps to end the war.

Not to nitpic, but Olympic's plans didn't include full occupation of the island.

 

[Blackfox5]

Here are the probable major ramifications.

Britain retakes Burma, Malaysia and Singapore in 1945.

Soviets take Manchuria, Korea, Dalian and probably Beijing in 1945.

Nationalist China with US support takes Canton (Guangzhou) and probably moves to Shanghai after the Japanese Army collapses between the Soviet and Chinese attacks combined with the continued US submarine campaign that eliminates supplies. There is probably a line just south of the Yellow River which marks the area of Nationalist control and Soviet/CCP control.

The US invades and seizes the souther half of Kyushu. Only if Japanese resistance collapses would US troops bother to seize the northern half.

Japanese probably massacre all Allied prisoners of war that they can, hardening Allied resolve.

At this point, what does Japan do? It has lost China. Although there are still troops in the East Indies and Indochina, they are completely cut off. The Allies can seize them if they think the gains are worth the losses. If not, they will let them wither on the vine. So does Japan surrender? I think the peace faction will gain control, only to be overthrown by a violent coup. The Emperor will be placed under polite house arrest to save him from the bad influences of traitors.

First bomb is dropped, then the second. Japan surrenders anyway. Thousands probably starve to death in the meantime due to the Allied blockade. Because of increased casualties, the atomic bombing is probably greeted with even a greater cheer than they were IOTL.

China is probably permanently partitioned with a CCP government in the north and Manchuria. Korea is communist too. However, central and southern China remain in Nationalist hands. The prolonged war have probably had a beneficial effect on Chiang's government. He has been able to have the first real, large infusion of American aide in the past 9 months or so. His troops have the morale boosting experience of handing the Japanese Army their hats in a series of victories. Chiang, under American influence, might even take steps to centralize his army's payroll. Knowing he doesn't have a chance of driving the Soviet/CCP out, he concentrates on internal reform while backing the inevitable American response to Soviet occupation of Eastern Europe and Northern China.

Given Soviet control in Korea and North China, the Vietnamese communists may get completely squeezed out in favor of non-communist Vietnamese. But this is extremely complicated due to whatever the French actually decide to do.

Cold War probably starts sooner.