Earliest possible defeat of Japan?

Assuming the Pacific War still begins on December 7, 1941 with the Pearl Harbour strike, what is the earliest date when Japan could be brought to capitulation?

What would be neccessary to achieve this and what are the immediate effects of this?
 
If you have a isolationist president that does not want to get in a war with Europe again but has their hand forced by japans attack, you might get a USA that participates in the pacific only (just make sure Germany does not declare war on the USA) with this happening you can get theoretically near 100% of the USA's focus on the pacific without a European theater, depending on how much material aid they send to Europe, if any.
 
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Assuming the Pacific War still begins on December 7, 1941 with the Pearl Harbour strike, what is the earliest date when Japan could be brought to capitulation?

What would be neccessary to achieve this and what are the immediate effects of this?
What PODs are allowed ie pre PH is allowed as long as it doesn't change it or not....?

Ie for example can you give USN working MK 14 torpedoes from 31 but nobody realises?
 
Yes, it obviously matters what we're allowed to change. Quickest I can think of is better intelligence has the American Pacific fleet ready to fight as the Kido Butai approaches Pearl Harbor, positioned to counter-attack as soon as the Japanese move. Naval battles of the era involved a lot of luck; have the breaks favor the U.S., and the destruction of much of the IJN's strength in that battle becomes possible. U.S. follows up by moving fleet to Manila, from which they can interfere with Japanese supply lines and use shore bombardment to harass the invasion forces; again, with some luck maybe the Philippines hold (ideally also scrape together some reinforcements as well). Such a large U.S. force in the area, and a heavily weakened IJN, would also greatly reduce the gains the Japanese could make against the Allies in the Indies. It still would take a while for the U.S. to ramp up for major offensive operations, but following Pauh's suggestion and having the U.S. ignore Europe means, for example, the forces used for Torch could be used against Japanese positions, so the Japanese could be losing ground quickly before 1942 ends, and I could see them besieged in the home islands in 1943. Hard to get more exact with the dates, as this would involve massive departures from OTL, of course. Also not clear at what point the hopelessness of their position would produce a surrender; they were pretty stubborn, and if we're trying to make it happen earlier nukes won't be available, but the fact that in this scenario the Japanese do not have a string of early successes to bolster the prestige of the military may make the militarists more vulnerable and less able to control policy. Without a surrender, an invasion of the home islands would involve a huge amount of preparation; again, since we're assuming the U.S. isn't involving itself in Europe, perhaps they might be ready around when they were ready for Normandy OTL. My thoughts, anyway.
 
Query, assuming US intelligence correctly guesses Japan's plan and they are heavily defeated at Pearl Harrbor and in the Ocean aftrerwards what happens to the Phillipines and also Singapor
 
1944 to completely isolate Japan. *
This is predicated on taking ~ two years to build a fleet carrier, and the same period to build the USN submarine fleet (and supporting operations) to 1945 levels.
Assuming the US devotes 100% of assets to Pacific production greatly increases production but capital ship construction times are assumed to be unchanged.

Submarines will begin to blanket Japan in 1943 and should complete by 1944.
The Fast Carrier Task Force was in action starting in January 1944. Essex class carriers really started hitting production in mid 1943. Assuming massive overproduction, the USN begins to embarrassingly outnumber Japanese carriers in late 1943 with or without a Midway type victory.

Assuming no Midway, island hopping begins in 1943 but moves at a faster rate than historically. Midway was needed for Guadalcanal / Tarawa to reduce IJN strength sufficiently, and even then led to a series of grinding battles in 1942 / 1943. Without Midway these occur, but later once the USN has built a higher number of carriers. Thereafter, they can move quickly, with both Marine and Army units. Twenty divisions of the Army moving south, with five to ten marine divisions island hopping as was done historically.

*The following is my opinion and is based on nothing but Wiki. ON the positive I have stayed at a Holiday Inn.
 
A dud German torp, Operation Judgement with fekkin huge bells on, Malta massively reinforced between Nov 40-April 41 and no Greek adventures beyond aircraft support for the Greeks

HMS Courageous is badly damaged by a single torpedo on 17th Sept 1939 and spends 6 months being repaired and modernized (pod is a second fish went clang rather than kaboom which happened rather a lot early in the war)

A 3 carrier strike (Illustrious, Ark Royal and Courageous) on the Italian fleet with 50 odd torpedo carrying aircraft sink all of the BBs in Taranto as well as most of the Cruisers firmly placing the initiative in the Med to the RN - certainly for 42 resulting in fewer losses and a reduced commitment to 'our sea'

Malta is provided with the 50 odd supply ships worth of supplies and equipment that was originally proposed (and the measly 16 it received) turning it into a true a proper base with which to interdict Axis logistics between Italy and Libya from early 1941 with Ship, Submarine and Aircraft.

Spitfires are freed up (prized from the grip of) from Fighter command earlier than they were and a more robust air defense of the island is undertaken....earlier

Some Squadrons also make their way to North Africa and these give JG 27 a really hard time

This has the knock on effect that it takes longer for the Africa Korps to stand up forces in Africa.

The Australian and NZ commanders question the commitment of their forces to the Greek campaign (rather than just accept what they were told) and before this is resolved at a commonwealth level the Germans invade

With Commonwealth forces not weakened by those units committed to the Greek campaign (and the subsequent men and equipment not lost etc) and the weaker Africa Korps resulting in the Operation Sonnenblume not being launched and Axis forces in North Africa remain on the Back foot into late 41.

But Cry what the F^%& has this got to do with Beating the Japanese earlier????

Well I am glad you asked.

With the campaign in North Africa going far better more attention is paid to the situation in French Indochina and as a result the 2nd Australian Imperial force is gradually redeployed back to the region and the strategy to defend Malaya and the various outposts and islands is spearheaded by that formation.

With better aircraft and better squadrons in North Africa...earlier....several extra wings of P40s and Hurricanes are freed up for service in the far east

With an improved situation in the Med and fewer losses overall a true fleet in being can be maintained in Singapore

When the Japanese attack they have to use forces originally allocated to the invasion of PH replacing them with weaker Divisions/regts to reinforce the attack into Malaya.

It proves not to be enough with the 3 fully leaded Australian divisions giving Yamashitas 25th Army a bloody good kicking and forcing it back to the Kra Peninsula

Fighting in PH bogs down well into 1942 and following the annihilation of the KB mid 42 in a series of attritional sea battles the US reinforces the PH securing the nation by early 43.

And so on and so forth...…...
 
Submarines will begin to blanket Japan in 1943 and should complete by 1944.

I recall in A Glorious Way to Die, Starr noted that by 1945 Japan was in a state of economic ruin. US subs had destroyed most of its merchant fleet, shutting off vital imports including oil. Starr wrote that "properly directed from the start, a US submarine campaign could have reduced Japan to this state over a year earlier." (Something like that.) If that is true, subs alone could've essentially beaten Japan by around the start of 1944.
 
I recall in A Glorious Way to Die, Starr noted that by 1945 Japan was in a state of economic ruin. US subs had destroyed most of its merchant fleet, shutting off vital imports including oil. Starr wrote that "properly directed from the start, a US submarine campaign could have reduced Japan to this state over a year earlier." (Something like that.) If that is true, subs alone could've essentially beaten Japan by around the start of 1944.
But what's the end game? A blockade alone might have starved millions of civilians, but by itself would never have convinced the military to surrender. You would probably still have to wait for the bombs to be ready.
 
But what's the end game? A blockade alone might have starved millions of civilians, but by itself would never have convinced the military to surrender. You would probably still have to wait for the bombs to be ready.

Agreed the only way to have it end sooner is to begin the Manhattan project sooner OR make some breakthroughs faster (although I believe they were pretty lucky as it was and you couldn't expect to shorten the process much) So you have the scientists get the letter to Roosevelt six months sooner and the war can end six months sooner. Without the bomb I don't think you can apply a big enough shock to keep the Japanese from fighting on and on until Halsey's prediction comes true.
 
Excellent answers already given and thank you. Lots of different events would have to come together. The USN doing things differently and soundly defeating the Japanese at Pearl Harbor. They turn it into a perfect ambush. Hitler never declares war on the USA. The USA concentrates on a short brutal Pacific War.

The USA does not declare war on Germany. Only Japan. Lots of other stuff also. Better USN torpedoes. Earlier proximity fused artillery shells down to 40 mm. If everything comes together along with the possibly earlier deployment of a better B29 heavy bomber and earlier island hopping. All quite possible.

Japan surrenders as early as 1944? Dunno.
 
Earlier POD

France starts proper rearmament earlier and come Sept 1939 Germany takes the threat of war that much more seriously in the face of a re-energised French military and backs down from the planned invasion of Poland and WW2 is stillborn.

....but that's no fun is it!?
 
But what's the end game? A blockade alone might have starved millions of civilians, but by itself would never have convinced the military to surrender. You would probably still have to wait for the bombs to be ready.

The Navy knew he war was lost when the Marianas defense collapsed. However they had effectively lost voting rights by losing their part of the War. The Army felt they were still winning & the Zaibatsu who backed them continued to do so. So, the trick is to convince the Army or Zaibatsu the war is lost sooner.

OTL three major events occurred in the 30 days preceding the decision to surrender. 1. The report on the annual rice harvest came in later July. It was extremely negative. Combined with the reports and estimates for the food supply in the next 6-9 months it was clear famine could be expected during the winter & probably no relief in the spring.

2. The Soviet DoW vaporized the strategy of the diehards. They had argued the differences between the USSR & the West Allies could be exploited to use the USSR as a materials source, and turn it into a defect ally of Japan. That strategy was still born and the lack of response to Japanese overtures should have been clear, but the proponents were in denial. The DoW left them with a impossible strategic position.

3. The air bombardment, which now included precision Navy raids as well as area bombing, was destroying Japans industry and infrastructure. The Atomic bombs were kick in the face to a opponent already dropping to the floor.

The Army offered a plan to cut off or eliminate non Japanese from food consumption, and any Japanese not productive. Plans were organized to kill the PoW, criminals, ect... disqualify non Japanese minorities like the Ainu for rations, ect... Some claim there is no evidence these plans would have been carried out. But, the fact that they were made, and preparations made, underlines the lengths the hard core factions were willing to consider. But, if you can get all of these three conditions in 1944 then there may be a small chance Japan will cease fighting with minimal armistice/peace conditions.

Yes, it obviously matters what we're allowed to change. Quickest I can think of is better intelligence has the American Pacific fleet ready to fight as the Kido Butai approaches Pearl Harbor, positioned to counter-attack as soon as the Japanese move. Naval battles of the era involved a lot of luck; have the breaks favor the U.S., and the destruction of much of the IJN's strength in that battle becomes possible. U.S. follows up by moving fleet to Manila, ...

As things stood in 1941 or 1942 Manilla could not support the 'fleet'. It was sufficient to support the Asiatic fleet, & a temporary visit by a larger fleet, but its facilities could not 'base' the Pacific fleet or a significant portion of it. In 1944-1945 the USN had its mobile base or fleet train, that allowed Manilia or any decent protected anchorage to serve as a long term base for the Pacific fleets. The first real fleet train was available in latter 1943 & used for the follow up to Op GALVANIC & preparations for subsequent operations. Like rebuilding the carrier fleet with the new Essex class its difficult to find a PoD that allows the fleet train much sooner that mid 1943.
 
Serious economic sanctions after the invasion of Manchuria. Militarists seen as failures

This is a interesting idea. I suspect it requires a stronger Chinese government & 'China Lobby' from the late 1920s.

Chiang Kai-shek proposed a "fundamental solution" to bomb the Japanese fleet and wanted US to equip them https://www.ibiblio.org/hyperwar/USA/USA-CBI-Mission/USA-CBI-Mission-1.html#fn8

(do not know if the Germans could have helped them with a smaller scale effort? earlier)
 
I recall in A Glorious Way to Die, Starr noted that by 1945 Japan was in a state of economic ruin. US subs had destroyed most of its merchant fleet, shutting off vital imports including oil. Starr wrote that "properly directed from the start, a US submarine campaign could have reduced Japan to this state over a year earlier." (Something like that.) If that is true, subs alone could've essentially beaten Japan by around the start of 1944.
If Japan was defeated primarily by a submarine campaign in 1943 and 1944, then would unrestricted submarine warfare be seen as almost equivalent to atomic bombs in power for a few years?
 
Chiang Kai-shek proposed a "fundamental solution" to bomb the Japanese fleet and wanted US to equip them https://www.ibiblio.org/hyperwar/USA/USA-CBI-Mission/USA-CBI-Mission-1.html#fn8

(do not know if the Germans could have helped them with a smaller scale effort? earlier)

For the Germans no. The Luftwaffe had very limited experience at attacking ships & that after 1937. In 1939 a sortie by the RN far into the North Sea resulted in Gobbels organization faking photographs of German aircraft attacking them. The bomber groups sortied had such poor overwater navigation skills they could not intercept. It took the German air force two years to build up to the point where they could inflict serious losses on the Brits at sea, re: Op PEDESTAL.

Bpmbing Japanese ports could have been done by the German AF of that era. tho I'd have some questions about bomber range, and numbers available.
 
I recall in A Glorious Way to Die, Starr noted that by 1945 Japan was in a state of economic ruin. US subs had destroyed most of its merchant fleet, shutting off vital imports including oil. Starr wrote that "properly directed from the start, a US submarine campaign could have reduced Japan to this state over a year earlier." (Something like that.) If that is true, subs alone could've essentially beaten Japan by around the start of 1944.

A thorough research and development plan for USN torpedoes, starting as early as 1919, and with support from the highest levels could have ironed out the massive and deeply set problems experienced by the USN with torpedo performance. With all else being the same, I am convinced that if we had gone to war loaded to the gunwales with excellent torpedoes the war could have ended by March 1945, possibly earlier.

See the threadmarked posts here: https://www.alternatehistory.com/fo...ish-the-great-torpedo-scandal-avoided.434935/
 

Dave Shoup

Banned
Assuming the Pacific War still begins on December 7, 1941 with the Pearl Harbor strike, what is the earliest date when Japan could be brought to capitulation? What would be necessary to achieve this and what are the immediate effects of this?

The US had begun mobilization in October, 1940, was attacked in December, 1941, and (historically) was able to stop the last strategic Japanese offense dead in June, 1942, and begin counteroffensives in the Pacific in August, 1942 and in the EAME in November, 1942. As stated above, the fast carrier force, ocean-going amphibious forces, and service/replenishment forces were available in strength in the autumn of 1943 ... so a Central Pacific offensive could have begun in the second or third quarters of 1943, rather than the fourth. Driving west through Micronesia to the Philippines, historically, took about nine months; the same time frame - if the Central Pacific offensive begins in the summer of 1943, rather than the winter of 1943 - gets US forces to the PI in the spring or summer of 1944. Once the US has sufficient land bases in the PI, liberation can proceed shore to shore, rather than ship to shore, which frees the fast carriers and ocean-going amphibious forces for driving north to the Bonins and Ryukyus. That puts the US forces in the position they were historically in 1945 in 1944, which suggests the combination of blockade and air attack sufficient to force a Japanese surrender historically could have been in place six to nine months earlier than historically.
 
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