AH Challenge: Japan Falls Before Germany

Conditions:

1) A POD no earlier than late December 1941
2) German surrender happens essentially on schedule
3) The US and Britain firmly support a Germany-first strategy
4) The Soviets do not declare war on Japan before February 1941 at the earliest
5) The atom bomb becomes usable no earlier than it did historically.

Given those conditions, how could we end up with Japan falling before Germany in the fewest possible points of divergence?
 
For a small couple of PoDs, save at least 2 of the 4 fleet carriers lost in 1942, particularly Lexington. I'd think saving a few of the big decks early in the war might allow for OTL's schedule to move up a bit thanks to carrier compound interest?
 
Conditions:

1) A POD no earlier than late December 1941
2) German surrender happens essentially on schedule
3) The US and Britain firmly support a Germany-first strategy
4) The Soviets do not declare war on Japan before February 1941 at the earliest
5) The atom bomb becomes usable no earlier than it did historically.

Given those conditions, how could we end up with Japan falling before Germany in the fewest possible points of divergence?

Better US torpedoes is probably the easiest POD. Second might be large scale use of aerial and submarine mining as early as possible. Why this was not done in OTL is somewhat mysterious as there were succesfull examples from European theatre of war since 1939.
 
Figuring out the US torpedo problems would undoubtedly help too. Not sure how much or in what way, though in 1943 one submarine was in ideal position to fire at no less than three Japanese aircraft carriers, fired ten torpedoes and had seven of them explode, all but one of them too far away from the ships to cause noticeable damage. Net result: One carrier with minor damage. (Hiyo - out of war for 3 months). Junyo escaped without damage, as did escort carrier Taiyo.

Premature detonation due to a faulty magnetic trigger was one of the three most major problems of the Mark 14 and to some extent the Mark 15 torpedoes. The other two: They ran ten feet too deep and if they actually got a direct hit, the firing mechanism broke about 70% of the time. They also tended to run circular paths and took out at least one of the firing subs.

US submariners fired around 800 of these turkeys before the navy finally did actual live tests with actual warheads in June 1942, but that only solved the running too deep problem. That made the other problems more visible, but it took over another year before most of them got solved. We did end up with a really reliable torpedo toward the end of the war.
 
Better US torpedoes is probably the easiest POD. Second might be large scale use of aerial and submarine mining as early as possible. Why this was not done in OTL is somewhat mysterious as there were succesfull examples from European theatre of war since 1939.

Yep! Sorry. X-posted.
 
(It was taken for a discontinued "The Anti-FaT" draft, with some adjustment because of the "POD no earlier than late December 1941" rule.)

Mark 14 torpedoes problems were fixed sometime on spring 1942.

May 1942 - Battle of the Coral Sea - While Takeo Takagi’s Carrier Division 5 mistaken Neosho and Sims as USN’s capital ships as IOTL, Frank J. Fletcher’s TF 17 found Carrier Division 5 instead of OTL Covering Group/Main Body Support Force (with light carrier Shōhō). Fleet carrier Shōkaku and Zuikaku was heavily damage, and Operation MO was called off immediately as a result. Some remaining planes from Shōkaku and Zuikaku did manage to took off following USN strike package and attack TF 17, both Lexington and Yorktown took a direct bomb hit. Surviving IJN pilots thought both USN fleet carrier were heavily damage, IJN high command brought their story and proceed with Operation MI/AL.

(Note: USS Wasp [CV-7] stay at Atlantic for the duration of the War ITTL)

June 1942 - Battle of Midway - The Pearl Harbor Naval Shipyard worked around the clock and fixed both Lexington and Yorktown. Akagi , Kaga and Sōryū were sunk as IOTL, Hiryū air group strike back at TF 17 as IOTL, but with the present of Lexington, the CAP force were stronger than OTL, IJN planes attack Lexington instead of Yorktown, more planes were shot down and Lexington suffer lighter damage than OTL Yorktown, I-168 failed to find Lexington. Hiryū was duly overwhelmed and sank by USN counter strike as IOTL, but Mogami and Mikuma collision were butterfly away though.

Aug. 1942 - Operation Watchtower - Jack Fletcher decided not to withdraw, cover transports till they finished their unloading. SBDs on scout bombing mission found and attack Gunichi Mikawa’s Cruiser Division 6 at “the Slot” of Solomon Islands. Damages were slight but Mikawa decided to return to Rabaul. Battle of the Eastern Solomons play out like OTL.

Sept. 1942 - I-26 torpedoed Saratoga as IOTL. I-19 sank Lexington (instead OTL Wasp, which also hit by four torpedoes instead of OTL three) and O'Brien (DD-415) but missed North Carolina.

Oct. 1942 - Battle of the Santa Cruz Islands - Yorktown join alongside with OTL Enterprise and Hornet, North Carolina was also available, therefore USN processed even stronger AA firepower. By the end of the battle, Yorktown and Shōhō was sunk. Shōkaku, Zuikaku and Zuihō was heavily damage, IJN lost even more planes than OTL.

13th Nov. 1942 - Naval Battle of Guadalcanal - William Halsey, Jr. decided to dispatched all three fast battleships North Carolina, Washington and South Dakota (under Willis A. Lee's command) to Ironbottom Sound, alongside with OTL Daniel Callaghan's cruisers force. As a result, accurate radars direct 16’in gunfire annihilated Hiroaki Abe’s force, battleship Hiei and Kirishima were sunk. After the battle, Japanese GHQ decided to abandon Guadalcanal. Since by that point the oil traffic between Brunei and Dutch East Indies was seriously disrupted by USN submarines force, Combined Fleet settle at Brunei (instead of Turk IOTL), so that they could refuel directly.

With two more Carriers (Yorktown and Hornet. CV-12 was named USS Kearsarge, and CV-33 was named USS Reprisal ITTL) available for Allies, Eastern Solomon and New Guinea Campaign in 1943 played out about one to two months faster than OTL, and the Central Pacific Offensive began one month sooner than OTL.

By the end of 1942, Japanese knew they’re beginning to lost the “Tonnage War” (it also made reinforcement and supply oversea territories very diffcult, Allied casualty of Island Hopping Campaign would be less serious ITTL), they estimated that if the trend continued, at the end of 1943, sea lane between Japanese Home Islands and “Southern Resources Area” would be virtually cut off.

In order to prevent these strategic catastrophes, Japanese occupied areas of China and South East Asia must be completely link up, so that a shorter sea lane between Occupied China and Japanese Home Islands could be used instead. Hence the Tairiku Datsū Sakusen (大陸打通作戦). In other words, Operation Ichi-Go, took place (and causing the downfall of Joseph Stilwell) one year earlier than OTL.Strategic wise, it only made South East Asia - Japan transportation form nearly impossible to very difficult. By late 1943, Japanese at home island were under harsh ration, worst among all major Belligerents. The fuel reserve was only enough for IJN to fight one last Major battle.

Fast-forward to May 1944, Invasion of Saipan and Battle of the Philippine Sea took place ITTL. IJN threw the dice and adopt an OTL Operation Shō-Gō 1 like game plan: using the carriers task force as bait to lure away 5th Fleet, while the Battleships could took on and wipe out the 7th Fleet, alongside the Invasion force.

IJN air strike play out like OTL "Great Marianas Turkey Shoot", while Raymond A. Spruance decided to pursuit and took out the Japanese carriers task force once and for all, he left Vice Admiral Willis A. Lee's TF 58.7 fast battleships to cover the 7th Fleet.

The night action off Saipan was the last all big guns action of Naval History. While Yamato and Musashi's main guns manages to inflict some damage on Iowa and New Jersey, but the superior American radar fire control made the different, Nagato, Kongo, Haruna, Fuso, and Yamashiro were sunk quite early on, two remaining super-battleships were reduced into floating wreckage, and add insult into injuries, old battleships of the 7th Fleet joined the fray, some of them were salvage from Pearl Harbor, it's payback time.

Battle of the Philippine Sea end as a near complete annihilation of IJN. Kamikaze became the only marginal effective mean to inflict damage on USN, but it can't prevent the liberation of Philippine.

By late 1944, Curtis LeMay took over both XX Bomber Command and XXI Bomber Command. He implement incendiary bombing and aerial mining as well, the later condemn Japan Home Island into state of famine.

On New Year Day 1945, upon reading report of rice riot in Sapporo, in addition of cannibalism at remote villages of Karafuto and Northern Hokkaido, he decided enough is enough and order Minister of Foreign Affairs to covertly sent out peace feeler via neutral country channel.

After an intense debate, FDR's cabinet agreed to made a critical concession to Japan: Kōshitsu would be preserve. By the end of January and on the eve of Yalta conference, Japanese throughout the Empire were heard the Gyokuon-hōsō, Japan was surrender sooner than Germany.
 
The night action off Saipan was the last all big guns action of Naval History. While Yamato and Musashi's main guns manages to inflict some damage on Iowa and New Jersey, but the superior American radar fire control made the different, Nagato, Kongo, Haruna, Fuso, and Yamashiro were sunk quite early on, two remaining super-battleships were reduced into floating wreckage, and add insult into injuries, old battleships of the 7th Fleet joined the fray, some of them were salvage from Pearl Harbor, it's payback time.

Interesting. I think that without Yamato and Musashi being sunk by aircraft, the US Navy's switch from battleships to aircraft carriers would either be butterflied away or occur slower than OTL.
 
Difficult...

Conditions:

1) A POD no earlier than late December 1941
2) German surrender happens essentially on schedule
3) The US and Britain firmly support a Germany-first strategy
4) The Soviets do not declare war on Japan before February 1941 at the earliest
5) The atom bomb becomes usable no earlier than it did historically.

Given those conditions, how could we end up with Japan falling before Germany in the fewest possible points of divergence?
The Japanese fail to capture anything remotely resembling usable oil installations in the first half year of their campaign against the Allies, and their military machine and economy literally run out of fuel at some point in 1943 or 1944.
Otherwise, with 'Germany first' and the other outlined conditions, I don't see any obvious, plausible, non-ASB way for Japan to sue for peace before the Germans do.
 
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Interesting. I think that without Yamato and Musashi being sunk by aircraft, the US Navy's switch from battleships to aircraft carriers would either be butterflied away or occur slower than OTL.
It was already occuring prewar. At most the last 2 Iowas and maybe 1 extra Alaska are finished, and the Iowas might be kept in service until Korea (OTL the US had only 1 BB in service by the start of the Korean war AFAIK)
 
The pre-war US pattern was that a group of three battleships operated together, accompanied by one aircraft carrier. I believe that as of 1941 the ratio of ships on order was at about that ratio.

Most US battleships in service as of 1941 were essentially World War I designs, because the Washington Naval Treaty and its successors decreed a battleship-building moratorium. As a result, all but the two newest US battleships were too slow to keep up with the carriers--but the carriers generally operated at the speed of the battleships. There were a few exceptions to that. When the navy wanted to ferry planes to Midway and Wake and get them there fast, they sent carriers out with heavy cruisers as escorts.

The official US Navy position as of Dec 7, 1941 was that a fully-crewed battleship at sea with room to maneuver was quite capable of dealing with aircraft. Were they right? Well, no US battleship at sea (as opposed to in harbor) was sunk by aircraft during World War II. The Brits lost a battleship or two due solely to aircraft and aircraft played a role in sinking the Bismark, but the US didn't lose any at sea to aircraft.
 
America gets delayed in the war with Germany for another year because Hitler does not declare war in December 1941. They pursue Japan first and starve it into submission by early 1945.
 

trurle

Banned
Conditions:

1) A POD no earlier than late December 1941
2) German surrender happens essentially on schedule
3) The US and Britain firmly support a Germany-first strategy
4) The Soviets do not declare war on Japan before February 1941 at the earliest
5) The atom bomb becomes usable no earlier than it did historically.

Given those conditions, how could we end up with Japan falling before Germany in the fewest possible points of divergence?

The solutions proposed before (i.e. more reliable US torpedo or changed outcome of a specific naval battle) can speed the demise of Japan by month or two. The majority of time was spent for killing the dug-in IJA island garrisons, not for naval warfare.
In actual history, Japanese in August 1945 were calculating to hold off the US onslaught until March, 1946 (until expiration of non-aggression pact with Soviets). They hoped for ceasefire with US sometime in January-February 1946, after tentative defeat of US invasion force and fleet on and around Kyushu island. And Japanese chances to defeat Kyushu invasion were not slim. Given this constraint, to surrender before Germany require war be shortened by at least a year (to make things bad enough to fail the Kyushu or other main island defence for sure).

Therefore, the standard history US strategy is not going to work to end the war by May 1, 1945. Even if Okinawa skipped, Iwo Jima was subdued only 27 March, 1945. So POD must be before Iwo Jima. Direct attack on Bay of Tokyo after rapid "island hopping" was also anticipated by Japanese and had all chances to fail.

But suppose..the Sheng Shicai in Xinjiang do not become hostile to USSR in 1942. In this case, the lend-lease material flows through Iran-Russia-Kazahstan-Xinjiang-China railroads instead of meagre amounts flown "over the hump" near the Burma-India front line.
The Chinese in 1943 instead of just stopping Japanese, deliver a full-scale rout to IJA (which always had a majority of forces on Chinese front, not on the Pacific).
By the early 1944, the US army have a friendly airbases as close to Japan as in Shanghai.
April 1944 - Chinese invasion to Taiwan, fully supported by US land-based aviation. Annihilation of IJN by airstrikes.
May 1944 - US and Chinese proceeding with Okinawa and Jeju islands
June-October 1944 - pause to wait until end of typhoon season. Strategic bombing of Japan
November 1944 - Invasion to Kyushu (1 year ahead of schedule)
February, 1944 - the general failure of Japanese defence of Kyushu, Japanese surrender.:(
 
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