How do I prevent the Soviet invasion of Manchuria?

Question

In an alternate timeline I am working on, I am aiming to keep the Japanese empire not only intact, but also large; a super power rivaling the USA and the USSR. The problem with this is the end of World War Two, America wanted unconditional surrender and would not allow this to exist. But I solved this by having Japan never ally with Hitler and thus they continue to be at peace with America.

But I soon came upon another problem: the Soviets. As much as America likes to believe, the Bombing of Japan had less to do with their surrender than the Soviets. In two weeks, USSR had managed to defeat all 700 thousands troops occupying Manchuria and Japan was terrified of this. Thus to allow Japan to keep Manchuria I need to prevent the Soviet Invasion of Manchuria, but how?

With a change not earlier than the 1920's, how can I prevent the USSR from invading Manchuria? What is the smallest change that can prevent this invasion?

Answer 1

The Imperial Japanese Army's "Northern Faction" wins the internal battles for Japanese Imperial policy in the late 1920's and early 1930's, and Japan moves into China, Manchuria and has long range plans to invade Siberia in order to access the resources available.

The Northern policy is seen as more desirable, since the resources are much closer to the Home Islands and delivering raw materials or goods and services is relatively easy and secure. This is in fact the history of OTL, up until the Japanese were defeated in the Battles of Khalkhin Gol.

For this not to happen, we need to look at Soviet history to that point. Soviet military theory was being driven by Marshal Mikhail Tukhachevsky's theories of "Deep Battle" and use of mechanized forces. This was in sharp contrast to the previous Russian preference for artillery and mass (although Tukhachevsky certainly did not overlook these aspects), and a large cadre of Soviet officers were being trained in these new theories.

However, Joseph Stalin was extremely suspicious of any potential power centres outside of his direct control, and on May 22, 1937, the Marshal was arrested and tortured. On June 11, 1937, Tukhachevsky and eight other Generals were placed before a special military tribunal, and eventually charged with treason and executed. One of Tukhachevsky's protege's who managed to escape being executed or even arrested, demoted or transferred from a combat command was General Georgy Zhukov, who led the Soviet forces against the Japanese in the Battles of Khalkhin Gol.

So the contrafactual would be to remove Zhukov through one of Stalin's mass purges, and have the Soviet forces in Manchuria led by a much less talented commander. The Japanese win and drive the Soviets out, leading to the Soviets having to maintain a large force in Western Siberia and being unable to transfer the troops to European Russia to fight the Nazi invasion in 1941. This could well lead to the fall of the USSR, or at the very least, reduce it to a sort of rump state clinging to their redoubts in the Urals mountains.

Stalin's paranoia knows no bounds, so even if the Japanese defeat the Soviets in detail in the Battles of Khalkhin Gol and its aftermath, he is hardly going to look for an independent minded commander who can operate at the end of a long communications and logistics line to fix things. Indeed, much like in 1941-42, he may attempt to dictate to the local commander and try to run the war from the Kremlin, although with the European situation changing on an almost daily basis, he may simply instruct the commander to "dig in" and repel any further Japanese incursions until such time that Stalin decides to go on the offence.

So increasing the scope of the Red Army's purges and eliminating the bulk of talented senior officers, including Zhukov, should prevent the USSR from having the ability to challenge the Japanese in Manchuria or Siberia, and since the Imperial Japanese Navy will no longer be abe to make the case for the "Southern Strategy" of taking manpower and resources from the Western Empires, one of the great drivers that made WWII a global conflict will be deleted. Even the American embargo of oil and steel will be far less effective if the Japanese Empire can simply ship raw materials from China and Korea, rather than trying to ship them from Indonesia or the Philippines.

This contrafactual effectively changes the entire character of WWII to an almost exclusively European conflict.

Answer 2

You have already made that change

America only got involved because Japan bombed Pearl Harbor. Since you have Japan at peace with the US, we can assume that Japan did not bomb Pearl Harbor. Thus, America is not in the war.

This means the Soviet Union has bigger things to worry about than Japan, namely Nazi Germany.

If America doesn't enter the war, the U-boat campaign is more successful against England, and England is less dangerous in secondary fronts in North Africa. Without England winning in North Africa, there is no invasion of Italy, and Italy stays on Germany's side in the war. And with no America, a reduced England, and a still-allied Italy, Germany can concentrate fully on fighting the USSR in 1943 and 1944.

Now this is no guarantee that the Germans will win the war against the Soviets, but it is likely that this war ends in some sort of bloody stalemate. Either way, stalemate, German or Russian victory, the Soviets won't have the spare troops to throw at Manchuria for years after 1945.

Answer 3

You'll need a stronger change to avoid war with the US

The US-Japan war chain of actions was only slightly related to the alliance with Hitler.

The Japanese actions in China and Indochina triggered an US embargo, and Japan really depended on the resources embargoed. After that, Japan had two options: Let their industry and everything asphyxiate, or try to take the US out of the western side of the Pacific.

Oh! And Japan wanted Phillippines, by then a colony of the US. That could be problematic.

Maybe you'd want to substitute Roosevelt with another Chamberlain or a fascist sympathizer.

But the question is about the USSR and peace with the US is an assumption.

Maybe the IJA is actually capable

In 1945, the Imperial Japanese Army stationed in Manchuria was a backwater occupation army, left with half of their theorical numbers and that half being essentially militia, the IJA being the long neglected branch of the armed forces and with a morale that could amount to a crap and half.

Okay, after finishing that paragraph I can not think of any way that the Manchurian army could hold their ground short of making them the focus of the overall strategy (i.e somehow the Siberian expansion axis would have been elected, but that's a total change that nullifies the context of the question).

So we're left with weakening the Soviet army, or preventing the invasion altogether.

Maybe the Nazis could chew what they bit, or at least for longer

By 1943 the Allies (including the USSR) were sure enough of victory against Germany that they planned what the USSR would do against Japan and started planning and allocating resources for the invasion of Manchuria.

Maybe the US is a true hermit and doesn't send materials to the USSR and that ends up hampering their war effort quite a bit. Maybe Moscow falls and the USSR suffers a heavy loss in leadership that prolongs the war some years. Maybe a time traveler convinces Hitler to stop being an idiot and prepare for winter, again prolonging the war.

Anything that makes the fate of the Nazi-Soviet war undecided in '43 and '44 makes any Manchurian plan nonsensical.

Maybe the USSR simply leaves Japan alone

Stalin's focus on gains after the war was in Europe and Japan being honorably neutral was really convenient for the USSR.
The most interested party in the Soviets aiding against Japan was Roosevelt. But here we're assuming the US sits on its butt so there is no push for Stalin to break the neutrality pact any soon.

So maybe you have already made that change, but for different reasons. :P