WI: Soviet-Japanese war... in 1940?

[Rufus]

The USSR and Japan fought a number of border skirmishes in the 30s, culminating in the battles of Khalkhin Gol in the summer of 1939. After getting a bloody nose, Japan decided to sign a ceasefire with the Soviets in September 39, and the two countries didn't clash again until the Soviet invasion of Manchuria in 1945. I've seen a few scenarios about a Soviet-Japanese war in the 30s, but I haven't seen any discussion about such a war happening after the outbreak of WW2, but before Barbarossa or Pearl Harbor.

So let's say Khalkhin Gol doesn't happen, and there is instead another incident in late 1939, leading to a series of engagements where the Japanese do better than OTL, which eventually leads to all-out war between Japan and the USSR in early 1940.

By late 1939 the Soviets had already invaded Poland, and were busy trying to invade Finland (which could make the Japanese more confident and aggressive, thinking the Soviets are distracted in Europe). What effects would a hypothetical Soviet-Japanese war at this point have, and what would be the reactions in Germany, France, Britain and the US?

I assume the French and British would be quite happy, since they regarded the Soviets more or less as a co-belligerent of Germany. Would war with Japan have any major impacts on the invasion of Finland? What would be the most likely outcome of such a war?

 

[Kaiser Wilhelm the Tenth]

I'm no expert by any means, but...
I imagine German-Japanese relations are pretty soured, at least in the short term.... Hitler probably won't be able to launch Barbarossa any earlier, given that the Low Countries/France still need to be conquered, the Italians will still make a mess of things in North Africa, etc.

As for Japan, a lot depends on how quickly the war ends. If they can get it over with in a year, then Pearl Harbour or something similar can still take place. If the Soviets are able to bog the Kwantung Army down in Siberia, that's when problems start for Tokyo... they've just created a second China-esque quagmire for themselves, and Stalin can always trade space for time. Perhaps we'd see the KMT/CCP being emboldened and trying larger-scale offensives?

The West would probably be happy... especially if this can butterfly away the Japanese occupation of Indochina in the summer of 1940.

Of course, if Moscow and Tokyo are still at war when Barbarossa is launched, the USSR will be in deep trouble.

But the real question is why? Why would the Japanese prioritise fighting the Red Army (which had already demonstrated its tactical superiority at Kahlkhin Gol) for the vast emptiness of Siberia over attacking the Southern Resources Territory? Especially given that if they waited too long, the American fleet ordered under the Two-Ocean Naval Expansion Act will start to come online (which it did to devastating effect in 1942/43), and then it's game over for Japan.

Just my two cents...

 

[dunHozzie]

It might actually help he Soviets. If Stalin postponed his attack on the Germans (or was that just a myth?) but more importantly move forces & supplies to the East, have better trained troops in 1941, the problem of dual command (political & line), the teething problems of T-34 (including the vision, radio and lack of separate commander) might be even more prominent and hopefully more known. Furthermore the Kwantung Army wasn’t a good unit afaik, even before it was hollowed out during the rest of the war. It was still missing a lot of equipment (eg anti tank, tanks, etc).

Between the Finns and the Japanese the Soviets get better troop experience, more in the east leaving less to be surrounded, early war economy and maybe even more importantly a more distrustful Stalin towards Hitler.

on the flip side, Stalin might be even more inclined to appease Hitler, the Axis armies used a lot of supplies provided by the Soviets to invade them, this might be even worse.

 

[Deleted member 9338]

I wonder, were is General Zhukov. Without Khalkhin Gol does he move up to the General Staff. If he is still in the east the Japanese may have a tough time of it. If he is in the West, well the Japanese may be in better shape. Dragging a Siberian campaign out for 18 months or so to get to Barbarossa is tough for the Japanese. What might be best for them is to look to the Soviet Union and not attack at Pearl Harbor. The British may pressure to keep the US suppling Japan at least until the summer of 1941.

 

[dunHozzie]

Zhukov is good, but what if they reestablish Konstantin Rokossovsky earlier. You’d be even more screwed

 

[BlackDragon98]

If Zhukov was killed during this war, it would be real bad for the USSR.

 

[BlackDragon98]

I'm no expert by any means, but...
I imagine German-Japanese relations are pretty soured, at least in the short term.... Hitler probably won't be able to launch Barbarossa any earlier, given that the Low Countries/France still need to be conquered, the Italians will still make a mess of things in North Africa, etc.

I agree, except Hitler might ditch Japan ITTL.
It's too far away and doesn't supply Germany with anything significant, unlike the USSR.
Come Pearl Harbor, he'll denounce Japan in a speech instead of OTL.

As for Japan, a lot depends on how quickly the war ends. If they can get it over with in a year, then Pearl Harbour or something similar can still take place. If the Soviets are able to bog the Kwantung Army down in Siberia, that's when problems start for Tokyo... they've just created a second China-esque quagmire for themselves, and Stalin can always trade space for time. Perhaps we'd see the KMT/CCP being emboldened and trying larger-scale offensives?

KMT Offensives would be catastrophic. All the good German trained KMT divisions were destroyed in Shanghai in the summer of 1940.
Those who survived and retreated to Nanjing were also destroyed.
The KMT spent 1938-1940 rebuilding it's armies, I doubt they'll try an offensive unless Japanese forces are seriously reduced in China to supply the Siberian Front.

The West would probably be happy... especially if this can butterfly away the Japanese occupation of Indochina in the summer of 1940.
Of course, if Moscow and Tokyo are still at war when Barbarossa is launched, the USSR will be in deep trouble.

But the real question is why? Why would the Japanese prioritise fighting the Red Army (which had already demonstrated its tactical superiority at Kahlkhin Gol) for the vast emptiness of Siberia over attacking the Southern Resources Territory? Especially given that if they waited too long, the American fleet ordered under the Two-Ocean Naval Expansion Act will start to come online (which it did to devastating effect in 1942/43), and then it's game over for Japan.

Just my two cents...

A Soviet offensive at Manchuria designed to force the Japanese to the bargaining table with the Soviets having the upper hand might cause this.
Manchuria was Japan's main raw materials producer and they relied on it extensively throughout WW2.
If the Soviets threatened it, they would definitely go to war over it, while digging in on the Chinese Front as the KMT has been militarily crippled after Shanghai and Nanjing and the ChiComs are not a major threat yet.

 

[nbcman]

Neither the Soviets nor the Japanese are stupid enough to try to do an offensive in the Far east during winter. By the spring of 1940, the Soviets would be watching Europe and wouldn’t want to escalate a conflict. The Japanese were hip deep in China and wouldn’t want to reinforce any hijinks by the Kwangtung Army after an unsuccessful series of campaigns in 1939.

 

[BlackDragon98]

Neither the Soviets nor the Japanese are stupid enough to try to do an offensive in the Far east during winter. By the spring of 1940, the Soviets would be watching Europe and wouldn’t want to escalate a conflict. The Japanese were hip deep in China and wouldn’t want to reinforce any hijinks by the Kwangtung Army after an unsuccessful series of campaigns in 1939.

What if the Soviets didn't attack Finland in 1940 and instead decided to attack Manchuria?
After their experiences at Khalkin Gol in 1939, they would have a good chance at defeating the Kwangtung Army and Japanese forces are still heavily invested in China.
Manchuria is already developed and confirmed to have several raw materials deposits and it's lightly defended compared to Finland.
And global sympathies are with China after Japanese war crimes in Shanghai and Nanjing.

 

[nbcman]

What if the Soviets didn't attack Finland in 1940 and instead decided to attack Manchuria?
I think with their experiences in 1939, they would have a good chance at defeating the Kwangtung Army and Japanese forces are still heavily invested in China.
Manchuria is already developed and confirmed to have several raw materials deposits and it's lightly defended compared to Finland.

The Germans even with the M-R pact were the greatest threat. The Soviets weren’t going to go on an offensive in Manchuria in the face of that threat considering they couldn’t supply enough forces via the TSRR to defeat the main body of the Japanese to capture Manchuria. There could be another border clash but it was in neither countries best interest to go further than that

 

[BlackDragon98]

The Germans even with the M-R pact were the greatest threat. The Soviets weren’t going to go on an offensive in Manchuria in the face of that threat considering they couldn’t supply enough forces via the TSRR to defeat the main body of the Japanese to capture Manchuria. There could be another border clash but it was in neither countries best interest to go further than that

The Soviets knew that the Germans were dependent on them for raw materials.
And the Japanese had their best forces in China.
Many of those defending Manchuria were low quality troops, Manchurians or Korean conscripts, most of whom would surrender pretty quick.

I think that a Soviet offensive in Manchuria is better than the OTL Winter War.
Soviets have the number advantage, more AFVs, and more aircraft.
And since this is a land war, the IJN is completely useless.

And they can expand the TSRR. After all, they have the materials and manpower.
Just use Gulag prisoners like they did when they build the White Sea Canal.

 

[LestWeForget]

What are the Japanese going to do against a country with 20,000 tanks? Did the Japanese even have a heavy tank design?

 

[BlackDragon98]

What are the Japanese going to do against a country with 20,000 tanks? Did the Japanese even have a heavy tank design?

They did, in 1945.
But it was crap compared to even the KV-1, which will definitely be deployed if the 2 come to blows.

 

[Rufus]

What if the Soviets didn't attack Finland in 1940 and instead decided to attack Manchuria?

The Soviets knew that the Germans were dependent on them for raw materials.
And the Japanese had their best forces in China.
Many of those defending Manchuria were low quality troops, Manchurians or Korean conscripts, most of whom would surrender pretty quick.

I think that a Soviet offensive in Manchuria is better than the OTL Winter War.
Soviets have the number advantage, more AFVs, and more aircraft.
And since this is a land war, the IJN is completely useless.

I wonder, if the Soviets attack Manchuria, how long would hostilities with Japan last until either side decides to make peace? I don't think either of them would be eager for a long, drawn out conflict at this point.

But if the war in the far east forces the Soviets to postpone their invasion of Finland by more than a year (and maybe their occupation of the Baltics and Bessarabia too), then the timing could work out quite badly for them:

Imagine if, after having settled things with Japan, they invade Finland in April or May 1941 or so, and also decide to occupy the Baltics and Bessarabia around the same time (as per M-R pact). If Barbarossa still happens on schedule, then the German invasion looks like a direct response to Soviet aggression.

Another question is if a war with the Soviets delays Japan's plans for its conquest of SE Asia. Would they still occupy Indochina while they're fighting the Soviets? If not, then the whole timeline leading up to the Pacific War would be pushed back.