AH Challenge: Defeat Japan as quickly as possible

With a PoD no earlier than December 12th 1941, make so that Japan unconditionally surrenders or is completely occupied much sooner than OTL.

Bonus points if it's before the end of 1942.
 
In a military way, this is not possible, but in the diplomatic negotiations, it could have been done so, without a single shot being fired.

Japan was only afraid of a two front war, including the USA in the East and the USSR in the North-West. In earlier skirmages, the IJA had been hit a bloody nose by the Red Army near Manchuria's Northern borders. Therefore, it considered the Russians to be a serious threath, which had to be neutralized, preferably by a pact of Non-Agression. Without this, the Japanese would cancel their entire war against the Western Powers.

So: the Allies, excluding the USA, which were still neutral at this time, would need to force their Soviet Ally, already at war on the side of the Allies against Germany, not to sign any treaty with Japan, just to keep the presure on Tokyo.
 

Markus

Banned
The Philippines:

The Philippine Division is moved within striking distance of Lingayen Gulf (in OTL recognized as the most likely invasion area). The Japanese invasion fleet disembarks the infantry like in OTL, the IJA brushes aside the units of the Philippine Army like in OTL and suddenly run into the well, armed, well trained and experienced soldiers of the Philippine Division. The advance is stopped, the casualties rise fast, calls for air-, artillery and tank support are made, but like in OTL the weather is bad and unloading has to be stopped, by the time its resumed the infantry ashore is beaten, tanks and artillery fail to turn the situation around.

A day later at Lammon Bay the Filipinos fall back slowly as the strategic reserve –the 4th Marine Regiment- races forward and stop them.

With their advance stopped, mounting losses and no reinforcements at hand the re-embarkation begins.

See also: Fall of the Philippines


Consolidating the Lingayen Beachhead
While his troops at Lingayen were pushing ahead, General Homma remained aboard ship in Lingayen Gulf. He had pushed his infantry and approximately half his armor ashore between Bauang and Agoo, but all the artillery save one regiment was still aboard the transports in the gulf. Cut off from his troop commanders, he had no way to lessen his apprehension by assurances that all was well.
There was some basis for General Homma's fears. The position of the Japanese troops ashore, while generally favorable, might easily become precarious. The landing had been made in a narrow corridor crossed by numerous streams, each of which afforded the defender an opportunity for delaying action. Although the plain to the south provided an excellent route to Manila,
[132]
it could also be used by the Americans and Filipinos as the base for a concerted counterattack against the Japanese as they streamed out of the corridor. A vigorous and well-timed attack by the four divisions of the North Luzon Force, spearheaded by the well trained and equipped Philippine Division in USAFFE reserve, might well "wipe out the invader." As the first day passed and no word came from the advancing troops, General Homma's fears increased. With no prospect of a calm sea in which to land his artillery and heavy equipment next day, and still fearing an American counterattack, he determined to shift anchorage.
Malaya:

When the first units of the 18th British Infantry division arrive, Percival uses the opportunity to concentrate his hitherto dispersed units. The 18th takes over the defence of Singapore Island, the Singapore garrison the beach defence of the Mersing area, relieving the crack 8th Australian. This division and the 9th Indian are engaging the Japanese together. The beaten 11th is send to the rear and rebuild- well, patched up as best as possible. The 8th has the opportunity to try the successful “trap-tactics” on a regimental instead of battalion level –in OTL an Aussie battalion hit the Japanese so hard they had to withdraw an entire regiment from the front for several days. Consequently the Japanese rate of advance is severely reduced, while their casualty rate is significantly increased. Enough to allow follow up units of the 18th Division to be re-routed to the ill-defended southern Sumatra.


Australia/New Guinea:

After receiving much good news from the Philippines and Malaya the fear of an invasion is rapidly declining and the government decides to send additional militia units from south-east Australia to New Guinea to engage and stop the Japanese as far forward as possible.


Good luck conquering SEA now suckers!
 
Awww, why the 12th? Force Z had already been sunk and the relief of Wake Island is too late.

Against Japan resources are so limited that schedule is king and atrittion is highly effective. Naval units lost in the initial invasions would never be properly replaced, so later battles would go better cause the acceleration of the war.
 
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