Hey guys, what you are about to listen to is basically a “what if” Japan performed Hokushin-ron instead of Nanshin-ron, ie: What if Japan invaded the USSR during WW2? Before I jump into it I just want to thank all of you that signed up for the patreon, you guys are awesome. Please leave a comment on this episode to let me know what more you want to hear about in the future. With all of that said and done lets jump right into it.
Part 1 The Geopolitical context
Ok so, one of the questions I get the most is, what if Japan invaded the USSR. I’ve actually already tackled this subject, albeit lightly with Cody from AlternatehistoryHub and once with my friend Eric. Its too complicated to give a real answer, a lot of this is guess work, though I really will try to provide hard numbers. I think off the bat something needs to be made clear since we are dealing with alternate history. I am not doing a “what if Japan developed completely different, or what if the IJA got their way in the early 1930’s” no no, this is going to be as realistic as possible…even though this is batshit crazy.
Japan faced the decision of whether to go to war with the USSR in 1941 during Operation Barbarossa. They held meetings, made plans, and ultimately it was decided they would not engage the Soviets. Our scenario will follow exactly what they did to a T, but when the made the decision not to go to war, we will see them go to war.
Now before I jump into our this timeline, I think its very important to explain the actual situation Japan faced in 1941.
There were two major strategies that emerged during the 1930’s within the Japanese military. Many junior officers in the IJA favored the Hokushin-ron “northern strike” strategy against the USSR. Many officers in the IJN with some in the IJA favored the Nanshin-ron “southern strike” strategy, to seize the resource rich dutch east indies by invading Southeast Asia and the Pacific. The idea of Hokushin-ron was to perform an invasion into Southern Siberia and outer mongolia ending around Lake Baikal where they would set up defenses. They had already tried to establish this during the Russian civil war as part of the Siberian Intervention, but failed to create a buffer state. From 1935-1939 there were 108 border clashes between the USSR and Japan. In 1938 one of these border clashes turned into quite a catastrophe, it was called the battle of Lake Khasan.
The Soviets suffered nearly 800 deaths, more than 3000 wounded, perhaps nearly 50 tanks were destroyed with another 100 damaged. The Japanese suffered about 600 deaths with 2500 wounded. The result ultimately was a ceasefire, but for the Kwantung army it seemed to them like a victory. In May of 1939 they had a much larger and more famous battle known as the battle of Khalkhin Gol.
During the early part of the battle the IJA sent 80 tanks crossing over Khalkhin Gol, driving the Soviets back towards Baintsagan Hill. Zhukov was waiting for the attack and sent 450 tanks and armored cars unsupported by infantry to attack the IJA from three sides. The IJA were practically encircled and lost half their armored units as they struggled to fight back as it withdrew. The two armies spared for the next 2 weeks along the east bank of the Khalkhin Gol. Problem was the Japanese were having issues getting their supplies to the area as they lacked motor transport while Zhukov whose army was over 460 miles away from its base of supply had 2600 trucks supplying them. On july 23rd the Japanese launched attacks supported by artillery and within two days they had consumed half their ammunition stores. The situation was terrible, they suffered 5000 casualties and made little progress breaking the Soviet lines. Zhukov then unleashed an offensive on august 20th using over 4000 trucks to transport supplies from Chita base. He assembled around 500 tanks, 550 fighters and bombers and his 50,000 infantry supported by armored cars. This mechanized force attacked the Japanese first using artillery and the aircraft as his armor and infantry crossed the river. The IJA were quickly flanked by the fast moving Soviet armor and encircled by August 25th. The IJA made attempts to break out of the encirclement but failed. They refused to surrender despite overwhelming artillery and aerial bombardment; by the 31st the Japanese forces on the Mongolian side of the border were destroyed. The Japanese suffered nearly 20,000 casualties, the lost 162 aircraft, 29 tanks, 7 tankettes, 72 artillery pieces a large number of vehicles. The Soviets took a heavy hit also suffering almost 25,000 casualties, 250 aircraft, 250 tanks, 133 armored cars, almost 100 artillery pieces, hundreds of vehicles.
While these numbers make it seem the Japanese did a great job, you need to consider what each party was bringing to this fight. The Japanese brought roughly 30,000 men, 80 tanks and tankettes, 400 aircraft, 300 artillery pieces, 1000 trucks. The Soviets brought nearly 75,000 men, 550 tanks, 900 aircraft, 634 artillery pieces, 4000 trucks.
There are some sources that indicate the IJA brought as many artillery rounds as they could muster from Japan, Manchuria and Korea, roughly 100,000 rounds for the operation. The Soviets fired 100,000 rounds per day. A quick look at wikipedia numbers, yes I know its a no no, but sometimes its good for quick perspectives show:
USSR: Bomber sorties 2,015, fighter sorties 18,509; 7.62 mm machine gun rounds fired 1,065,323; 20 mm (0.80 in) cannon rounds expended 57,979; bombs dropped 78,360 (1,200 tons).
Japan: Fighter/bomber sorties 10,000 (estimated); 7.7 mm (0.30 in) machine gun rounds fired 1.6 million; bombs dropped 970 tons.
What I am trying to say is there was an enormous disparity in military production. And this is not just limited to numbers but quality. After the battle the Japanese made significant reforms. They increased tank production from 500 annually to 1200. The Japanese funded research into new anti-tank guns, such as the Type 1 47 mm. They mounted this gun to their Type 97 Chi-Ha tanks, the new standard medium tank of the IJA. Because of the tremendous defeat to Soviet armor they send General Yamashita to Germany to learn everything he could about tank tactics. But they simply could not produce enough tanks to ever hope to match 10% of the USSR. The Soviets had mostly been using T-26’s, BT-5’s and BT-7’s who were crudely made, but made en masse. The Japanese would find most of their tank models with less effective range, less armor and some with less penetration power. It took the Japanese a hell of a lot more time to produce tanks, they were simply not on par with the Soviets in quantity or quality. Their tank tactics, albeit improved via Yamashita after 1939, were still nothing compared to the Soviets.
The major outcome of the battle of Lake Khasan and Khalkhin Gol was the abandonment of the hokushin-ron strategy and adoption of the nanshin-ron strategy. But, that didnt mean Japan did not have a plan in case they had to go to war with the USSR.
Part 2 Kantōgun Tokushu Enshū
Kantōgun Tokushu Enshū or the Kwantung Army Special Maneuvers was an operational plan created by the General Staff of the IJA for an invasion of the Russian Far East to capitalize on Operation Barbarossa. Here our story truly begin.
Between 1938-1939 the IJA General Staff and Kwantung Army formed two “Hachi-Go” plans. Variants A and B examined the possibility of an all out war with the USSR beginning in 1943. In both plans they expected to be facing 60 Soviet divisions, while they could deliver 50 divisions, delivered incrementally from China and Japan. Plan A called for attacks across the eastern and northern borders of Manchuria while maintaining a defensive stance in the west. Plan B, much more ambitious, called for striking into the vast steppe between the Great Khingan Mountains and Lake Baikal, hoping to cut off the trans-siberian railway. If this was done successfully it was believed the whole of European Russia would be doomed to be defeated in detail. Defeated in detail means to divide and conquer. This battle would take place over 5000 kilometers with Japan’s final objective being to advance 1200 km into the USSR. That dwarves Operation Barbarossa in distance, let that sink in. Both plans faced impossible odds. First of all the railway networks in Manchuria were not sufficiently expanded for such far reaching offensives, especially for plan B. Furthermore the 50 divisions required for them would be impossible to come by, since 1937 Japan was bogged down in a war with China. When Japan went to war with the west in 1941 she had 51 divisions. She left the base minimum in China, 35 divisions and tossed nearly 20 into southeast asia and the pacific. On top of not having the men, the IJA estimated a fleet of 200,000 vehicles would be necessary to sustain an offensive to Lake Baikal. That was twice the number of military vehicles Japan had at any given time. After the battle of Khalkhin Gol, plan B was completely abandoned. Planning henceforth focused solely on the northern and eastern fronts with any western advance being limited in scope.
Now Japan formed a neutrality pact with the USSR because of her defeat at Khalkhin Gol and Molotov Ribbentrop pact between Germany and the USSR. The Molotov Ribbentrop Pact came as a bitter and complete surprise to Japan. It pushed Japan to fully adopt the Nanshin-ron strategy and this began with her invasion of French IndoChina, which led the United Kingdom, the Netherlands and United States to embargo her. The Netherlands Dutch East Indies refused to sell oil to Japan, the UK refused to sell oil from Burma and the US gradually cut off selling oil to Japan, with her oil exports alone being 80% of Japans supply, the rest from the Dutch east indies. The United States also placed an embargo on scrap-metal shipments to Japan and closed the Panama Canal to Japanese shipping. 74.1% of Japan's scrap iron came from the United States in 1938, and 93% of Japan's copper in 1939. Other things like Rubber and tin were also off the table, as this was mostly acquired from British held Malaya and the Dutch East Indies.
Now the crux of everything is the China War. Japan was stuck, she needed to win, in order to win she needed the resources she was being denied. The only logical decision was to attack the places with these resources. Thus until 1941, Japan prepared to do just that, investing in the Navy primarily. Then in June of 1941, Hitler suddenly informs the Japanese that he is going to invade the USSR. The Japanese were shocked and extremely angry, they nearly left the Tripartite Pact over the issue. This unprecedented situation that ushered in the question, what should Japan do? There were those like Foreign Minister Yosuke Matsuoka who argued they must abandon the neutrality pact and launch a simultaneous offensive with the Germans against the USSR. The IJA favored this idea….because obviously it would see them receiving more funding as the IJN was currently taking more and more of it for the Nanshin-ron plans. But this is not a game of hearts of Iron IV, the Japanese government had to discuss and plan if they would invade the USSR….and boy it took awhile. I think a lot of you will be very disappointed going forward, but there is no grand unleashing of a million Japanese across the borders into the Soviet Far East, in the real world there is something called logistics and politics.
The Japanese military abided by a flexible response policy, like many nations do today. Theres was specifically called the Junbi Jin Taisei or “preparatory formation setup”. Japan would only go to war with the USSR if favorable conditions were met. So in our timeline the Junbi Jin encountered its first test on June 24th when the IJA/IJN helped a conference in the wake of operation barbarossa. A compromise was made allowing the IJA to prepare an invasion plan if it did not impede on the nanshin-ron plans. There was those in the IJA who argued they should invade the USSR whether conditions were favorable or not, there were those who only wanted to invade if it looked like the USSR was on the verge of collapse. One thing agreed upon was if Japan unleashed a war with the USSR, the hostilities needed to be over by mid-October because the Siberian climate would hit winter and it would simply be impossible to continue. The IJA needed 60-7 days to complete operational preparations and 6-8 weeks to defeat the Soviets within the first phase of the offensive. Here is a breakdown of what they were thinking:
28 June: Decide on mobilization5 July: Issue mobilization orders20 July: Begin troop concentration10 August: Decide on hostilities24 August: Complete readiness stance29 August: Concentrate two divisions from North China in Manchuria, bringing the total to 165 September: Concentrate four further divisions from the homeland, bringing the total to 22; complete combat stance10 September (at latest): Commence combat operations15 October: Complete first phase of warThe plan called for 22 divisions (might I add my own calculations of 20 divisions were pretty spot on), with roughly 850,000 men, including Manchukuo allies, supported by 800,000 tons of shipping. The Japanese hoped the Soviets would toss at least half their forces in the Far East, perhaps 2/3rd of their armor and aircraft against the Germans giving them a 2-1 superiority. Even the 22 divisions was questionable, many in the war ministry thought only 16 divisions could be spared for such a venture, something only suitable for mop up operations in the aftermath of a German victory along the eastern front. It was clear to all, Japan needed perfect conditions to even think about performing such a thing.
The War hawks who still sought to perform Hokushin-ron tried to persaude Hideki Tojo on july 5th to go through with a new plan using a total of 25 divisions. This plan designated “Kantogun Tokushu Enshu or Kantokuen” would involve 2 phases, a buildup and readiness phase and an offensive phase. On July 7th they went to Hirohito for his official sanction for the build up. Hirohito questioned everything, but gradually relented to it. The plan was nearly identical to the former plans, banking on the Soviets being unable to reinforce the Far East because of Germany’s progress. The level of commitment was scaled down somewhat, but still enormous. Again a major looming issue was the Manchurian railways that would need to be expanded to accomodate the movement of men and supplies. This meant the construction of port facilities, military barracks, hospitals and such. Kantokuen would begin with a initial blow against the Ussuri front, targeting Primorye and would be followed up by a northern attack against Blagoveshchensk and Kuibyshevka. The 1st area army, 3rd and 20 armies with the 19th division of the Korean army would penetrade the border south of Lake Khanka to breach the main soviet defensive lines, thus threatening Vladivostok. The 5th army would strike south of Dalnerechensk to complete the isolation of the maritime province, sever the trans-sierian railway and block Soviet reinforcements. The 4th army would attack along the Amur river before helping out against Blagoveshchensk. Two reinofrced divisions would invade Sakhalin from land and sea. The second phase would see the capture of Khabarovsk, Komsomolsk, Skovorodino, Sovetskaya Gavan, and Nikolayevsk. Additionally, amphibious operations against Petropavlovsk-Kamchatsky and other parts of the Kamchatka Peninsula were contemplated.
It was agreed the operation could only afford 24 divisions, with 1,200,000 men, 35,000 vehicles, 500 tanks, 400,000 horses and 300,000 coolies. The deployment of thse forces would mean the western front facing Mongolia and the Trans-baikal region would be pretty much open, so delaying actions would have to be fought if the soviets performed a counter offensive there. Air forces were critical to the plan. They sought to dispatch up to roughly 2000 aircraft cooperating with 350 naval aircraft to launch a sudden strike against the Soviet Far East Air Force to knock them out early.
The Soviet Far East had two prominent weaknesses to be exploited. Number 1 was Mongolia’s 4500 km long horeshoe shaped border. Number 2 was its 100% dependency on European Russia to deliver men, food and war materials via the trans-siberian railway. Any disruption of the trans-siberian railway would prove fatal to the Soviet Far East.
Now as for the Soviets. The 1930’s and early 1940’s saw the USSR take up a defensive policy, but retained offensive elecments as well. Even with the German invasion and well into 1942, the Soviets held a strategy of tossing back the IJA into Manchuria if attacked. The primary forces defending the Far east in 1941 were the Far Eastern and Trans-Baikal Fronts, under the command of Generals Iosif Apanasenko and Mikhail Kovalyov. The Trans-Baikal front held 9 divisions, including 2 armored, a mechanized brigade and a heavily fortified region west of the Oldoy River near Skovorodino had a garrison. The Far Eastern Front had 23 divisions including 3 armored, 4 brigades and 11 heavily fortified regions with garrisons including Vladivostok. Altogether they had 650,000 men, 5400 tanks, 3000 aircraft, 57,000 vehicles, 15,000 artillery pieces and nearly 100,000 horses. By 1942 the Vladivostok sector had 150 artillery pieces with 75 -356 mm calibers organized into 50 batteries. As you can imagine after Operation Barbarrosa was unleashed, things changed. From June to December, roughly 160,000 men, 3000 tanks, 2670 artillery pieces, 12,000 vehicles and perhaps 1800 aircraft were sent to deal with the Germans. Despite this, the Soviets also greatly expanded a buildup to match the apparent Japanese buildup in Manchuria. By July 22nd 1941 the Far Eastern and Trans-Baikal Fronts were to be raised by 1 million men for august. By December it was nearly 1.2 million. Even the Soviet Far East Navy saw an increase from 100,000 men to 170,000 led by Admiral Yumashev. The Soviet Mongolian allies were capable of manning about 80,000, though they lacked heavy equipment.
Thus if this war broke out in September the Soviets and Mongolians would have just over a million men, with 2/3rds of them manning the Amur-Ussuri-Sakhalin front, the rest would defend Mongolia and the Trans-Baikal region. Even though the war against the Germans was dire, the Soviets never really gave up their prewar planning for how to deal with the Japanese. There would be an all-out defense over the border to prevent any breach of Soviet territory. The main effort would see the 1st and 25th armies holding a north-south axis between the Pacific ocean and Lake Khanka; the 35th army would defend Iman; the 15th and 2nd Red Banner armies would repel the Japanese over the Amur River; and other forces would try to hold out on Sakhalin, Kamchatka and the Pacific coast. The Soviets had constructed hundreds of fortified positions known as Tochkas along the border. Most of these were hexagonal concrete bunkers contained machine gun nests and 76 mm guns. The fortified regions I mentioned were strategically placed forcing the Japanese to overcome them via frontal attacks. This would require heavy artillery to overcome. Despite the great defensive lines, the Soviets did not intend to be passive and would launch counteroffensives. The Soviet air force and Navy would play an active role in defeating a Japanese invasion as well. The air force’s objetice would be to destroy the Japanese air force in the air and on the ground, requiring tactical ground attack mission. They would also destroy key railways, bridges and airfields within Manchuria and Korea alongside intercepting IJN shipping. Strategic bombing against the home islands would be limited to under 30 DB-3’s who could attack Tokyo, Yokosuka, Maizuru and Ominato. The Soviet Navy would help around the mouth of the Amur River, mine the Tatar Strait and try to hit any IJN ships landing men or materials across the Pacific Coasts.
Japan would not be able to continue a land war with the USSR for very long. According to Japanese military records, in 1942 while at war they were required to produce 50 Kaisenbun. A Kaisenbun is a unit of measurement for ammunition needed for a single division to operate for 4 months. Annual production never surpassed 25 kaisenbun with 100 in reserve. General Shinichi Tanaka estimated for an operation against the USSR 3 Kaisenbun would be needed per divisions, thus a total of 72 would be assigned to 24 divisions. This effectively meant 2/3rds of Japans ammunition stockpile would be used on the initial strike against the USSR. Japan would have been extremely hard pressed to survive such a war cost for 2 years.
Now in terms of equipment Japan had a lot of problems. During the border battles, Japanese artillery often found itself outranged and grossly under supplied compared to the Soviet heavier guns. Despite moving a lot of men and equipment to face the Germans, the Red Army maintained a gross superiority in armor. The best tank the Kwantung Army had in late 1941 was the Type 97 Chi-Ha, holding 33mm armor with a low velocity 57 mm gun. There was also Ha-Go and Te-Ke’s with 37 mm guns but they had an effective range less than 1 km.
The Soviet T-26, BT-5 and BT-7’s had 45 mm guns more than capable of taking out the Japanese armor and the insult to injury was they were crudely made and very expendable. Every Japanese tank knocked out was far greater a loss, as Japan’s production simply could not remotely match the USSR. For aircraft the Japanese were a lot better off. The Polikarpov I-16 was the best Soviet fighter in the Far East and performed alright against the Nakajima Ki-27 at Khalkhin Gol. The rest of the Soviet air arsenal were much older and would struggle. The Soviets would have no answer to the IJN’s Zero fighter or the IJA’s high speed KI-21 bomber that outraced the Soviet SB-2. Japanese pilots were battle hardened by China and vastly experienced.
Another thing the Japanese would have going for them was quality of troops. The Soviets drained their best men to fight the Germans, so the combat effectiveness in the far east would be less. Without the Pacific War breaking out, some of Japan’s best Generals would be brought into this war, of course the first one that comes to mind for me is General Yamashita, probably the most armor competent Japanese general of ww2.
Come August of 1941 those who still sought the invasion of the USSR were facing major crunch time. The IJA planners had assumed the Soviets would transfer 50% or more of their power west to face the Germans, but this was not the case. By August 9th of 1941, facing impossible odds and with the western embargos in full motion, in our timeline the Japanese Hokushin-Ron backers gave up. But for the sake of our story, for some batshit insane reason, the Japanese military leadership and Hirohito give the greenlight for an invasion on August 10th.
So to reiterate the actual world plan had
10 August: Decide on hostilities24 August: Complete readiness stance29 August: Concentrate two divisions from North China in Manchuria, bringing the total to 165 September: Concentrate four further divisions from the homeland, bringing the total to 22; complete combat stance10 September (at latest): Commence combat operations15 October: Complete first phase of warSo what is key to think about here is the events of September. The Battle for Moscow is at the forefront, how does a Japanese invasion in the first week or two of September change things? This is going to probably piss off some of you, but Operation Typhoon would still fail for Germany.
In our time line the legendary spy Richard Sorge sent back information on Japan’s decision to invade the USSR between August 25th to September 14th. On the 25th he informed Stalin the Japanese high command were still discussing whether to go to war or not with the USSR. On September 6th Stalin was informed the Japanese were beginning preparations for a war against the west. Then on September 14th, the most important message was relayed to Stalin "In the careful judgment of all of us here... the possibility of [Japan] launching an attack, which existed until recently, has disappeared...."[15]
With this information on hand from 23 June to 31 December 1941, Stalin transferred a total of 28 divisions west. This included 18 rifle divisions, 1 mountain rifle division, 3 tank divisions, 3 mechanized divisions and 3 mountain cavalry divisions. The transfers occurred mainly in June (11 divisions) and October (9 divisions).
Here we come to a crossroads and I am going to have to do some blunt predictions. Let's go from the most optimistic to the most pessimistic. Scenario 1) for some insane reason, Stalin abandons Moscow and moves his industry further east, something the Soviets were actively preparing during Operation Typhoon. This is not a defeat of the USSR, it certainly would prolong the war, but not a defeat. Now that seems rather silly. Scenario 2) Stalin attempts transferring half of what he did in our time line back to Moscow and the Germans fail to take it. The repercussions of course is a limited counteroffensive, it wont be as grand as in our timeline, but Moscow is saved. Scenario 3) and the most likely in my opinion, why would Stalin risk moscow for the Far East? Stalin might not transfer as many troops, but certainly he would have rather placed his chips in Moscow rather than an enemy literally 6000 km’s away who have to cross a frozen desert to get to anything he cares about.
Even stating these scenarios, the idea the German army would have taken Moscow if some of the very first units from the far east arrived, because remember a lot of these units did not make it in time to defend moscow, rather they contributed to the grand counteroffensive after the Germans stalled. The German armies in front of Moscow were depleted, exhausted, unsupplied and freezing. Yes many of the Soviet armies at Moscow were hastily thrown together, inexperienced, poorly led and still struggling to regain their balance from the German onslaught. Yet from most sources, and by sources I mean armchair historian types argue, the Germans taking Moscow is pretty unlikely. And moscow was not even that important. What a real impact might have been was the loss of the Caucasus oil fields in early 1942, now that could have brought the USSR down, Moscow, not so much, again the Soviets had already pulled their industry further east, they could do it again.
So within the context of this Second Russo-Japanese War, figure the German’s still grind to a halt, they don’t take Moscow, perhaps Soviets dont push them back as hard, but the USSR is not collapsing by any means.
Ok now before we talk about Japans invasion we actually need to look at some external players. The UK/US/Netherlands already began massive embargoes against Japan for oil, iron, rubber, tin, everything she needed to continue her war, not just against the USSR, but with over 35 divisions fighting in China. President Roosevelt was looking for any excuse to enter WW2 and was gradually increasing ways to aid Britain and the Soviets.
Now American’s lend-lease program seriously aided the USSR during WW2, particularly the initial stages of the war. The delivery of lend-lease to the USSR came through three major routes: the Arctic Convoys, the Persian Corridor, and the Pacific Route. The Arctic route was the shortest and most direct route for lend-lease aid to the USSR, though it was also the most dangerous as it involved sailing past German-occupied Norway. Some 3,964,000 tons of goods were shipped by the Arctic route; 7% was lost, while 93% arrived safely.
The Persian Corridor was the longest route, and was not fully operational until mid-1942. Thereafter it saw the passage of 4,160,000 tons of goods, 27% of the total. The most important was the Pacific Route which opened up in August of 1941, but became affected when Japan went to war with America. The major port was Vladivostok, where only Soviet ships could transport non-military goods some 8,244,000 tons of goods went by this route, 50% of the total. Vladivostok would almost certainly be captured by the Japanese in our scenario so it won't be viable after its capture. Here is the sticky part, Japan is not at war with the US, so the US is pretty much free to find different Pacific paths to get lend-lease to the Soviets, and to be honest there's always the Arctic or Persian corridors. Hell in this scenario America will be able to get supplies easily into China as there will be no war in Burma, hong kong, Malaya and such. America alone is going to really ruin Japans day by increasing lend-lease to the UK, China and the USSR. America wont be joining the war in 1941, but I would strongly wager by hook or by crook, FDR would pull them into a war against Germany, probably using the same tactic Woodrow Wilson did with WW1. This would only worsen things for Japan.
Another player of course is China. Late 1941, China was absolutely battered by Japan. With Japan pulling perhaps even more troops than she did for the Pacific war to fight the USSR, Chiang Kai-Shek would do everything possible to aid his new found close ally Stalin. How this would work out is anyone’s guess, but it would be significant as I believe America would be providing a lot more goodies.
Ok you’ve all been patient, what happens with the war? Japan has to deliver a decisive knock out blow in under 4-6 months, anything after this is simply comical as Japan’s production has no resources. The oil in siberia is not even remotely on the table. The Japanese can’t find it, would not be able to exploit it, let alone quick enough to use it for the war. Hell the Italians were sitting on oil in Libya and they never figured that out during WW2.
So Kantokuen is unleashed with an initial blow against the Primorye in the Ussuri Front followed by an assault against Blagoveshchensk and Kiubyshevka. The main soviet lines south of Lake Khanka are attacked by the Japanese 1st area army, 3rd and 20th armies and the 19th Korean division. This inturn threatens Vladivostok who is also being bombarded by IJA/IJN aircraft. The 5th Ija army attacks south of Dalnerechensk in an attempt to sever the trans-siberian railway, to block Soviet reinforcements and supplies. The 4th IJA army fords the Amur river to help with the assault of Blagoveshchensk. Meanwhile Sakhalin is being attacked from land and sea by two IJA divisions.
Despite the Soviets being undermanned the western front facing Mongolia and the Trans-Baikal region is wide up to an attack as its only defended by the 23rd IJA division, so a limited counteroffensive begins there. The Japanese quickly win air superiority, however the heavily fortified Tochkas are not being swept aside as the Japanese might have hoped. A major problem the Japanese are facing is Soviet artillery. The Japanese artillery already placed along the borders, initially performed well, crushing Tochkas in range, but when the Japanese begin advancing and deploying their artillery units they are outgunned perhaps 3-1, much of the Soviet artillery outranges them and the Soviets have a much larger stockpile of shells. Airpower is failing to knock out soviet artillery which is placed within Tochkas and other fortified positions with anti-aircraft guns. Without achieving proper neutralization or counter battery fire, the Japanese advance against the fortified Soviet positions. The Soviets respond shockingly with counterattacks. The 15th and 35th Soviet armies with the Amur Red Banner Military Flotilla toss limited counterattacks against both sides of the Sungari River, harassing the Japanese.
While much of the soviet armor had been sent west, their light tanks which would be useless against the Germans have been retained in the far east and prove capable of countering the IJA tanks. The Soviets inflict tremendous casualties, however General Yamashita, obsessed with blitzkrieg style warfare he saw first hand in the west, eventually exploits a weak area in the line.Gradually a blitzkrieg punches through and begins to circle around hitting Soviet fortified positions from the rear. The Soviets knew this would be the outcome and had prepared to fight a defense in depth, somewhat managing the onslaught.
The trans-siberian railway has been severed in multiple locations close to the border area, however this is not as effective as it could be, the Japanese need to hook deeper to cut the line further away. In the course of weeks the Soviets are gradually dislodged from their fortified positions, fighting a defense in depth over great stretches of land. Vladivostok holds out surprisingly long until the IJN/IJA seize the city. Alongside this Sakhalin is taken with relative ease. The Soviet surface fleet is annihilated, but their large submarine force takes a heavy toll of the IJN who are attempting Pacific landings.
Kantokuen phase 1 is meeting its objectives, but far later than expected with much more casualties than expected. The Japanese are shocked by the fuel consumption as they advance further inland. Each truck bearing fuel is using 50% of said fuel to get to the troops, something reminiscent of the north african campaign situation for Rommel. The terrain is terrible for their vehicles full of valleys, hills, forests and mountains. Infrastructure in the region is extremely underdeveloped and the Soviets are burning and destroying everything before the Japanese arrive. All key roads and cities are defended until the Japanese can encircle the Soviets, upon which they depart, similar to situations the Japanese face in China. It is tremendously slow progress. The IJA are finding it difficult to encircle and capture Soviet forces who have prepared a series of rear lines to keep falling back to while performing counterattacks against Japanese columns. As the Japanese advance further into the interior, the IJN are unable to continue supporting them with aircraft and much of the IJA aircraft are limited in operations because of the range.
The second phase of Kantokuen calls for the capture of Khabarovsk, Komsomolsk, Skovorodino, Sovetskaya Gavan, and Nikolayevsk. Additionally, amphibious operations against Petropavlovsk-Kamchatsky and other parts of the Kamchatka Peninsula are on standby as the IJN fears risking shipping as a result of Soviet submarine operations. The sheer scope of the operation was seeing the tide sides stretching their forces over a front nearly 5000 km in length. At some points the Japanese were attempting to advance more than 1000 km’s inland, wasting ungodly amounts of fuel and losing vehicles from wear and tear.
So what does Japan gain? Within the span of 4 months, max 6 months Japan could perhaps seized: Sakhalin, the Primorsye krai including Vladivostok, segments of the trans siberian railway, Blagoveshchensk, Kuibyshevka. If they are really lucky Khabarovsk, Komsomolsk, Skovorodino, Sovetskaya Gavan, Nikolayevsk. Additionally, Petropavlovsk-Kamchatsky and other parts of the Kamchatka Peninsula. What does this mean? Really nothing.
Pull out a map of manchuria during WW2, take a pencil and expand the manchurian border perhaps 1000 km if you really want to be generous, that's the new extent of the empire of the rising sun. The real purpose of attacking the USSR is not to perform some ludicrous dash across 6000 km’s of frozen wasteland to whittle down and defeat the Soviets alongside the rest of the Axis. It was only to break them, in late 1941 at Moscow there was perhaps a fools chance, but it was a fool's chance for Japan.
Japan has run out of its stockpiles of Kaisenbun, oil, iron, rubber, tin, all types of resources necessary for making war. Unlike in our timeline where Japan began exporting resources from its conquests in southeast asia and the pacific, here Japan spent everything and now is relying on the trickles it has within its empire. The China war will be much more difficult to manage. The lend-lease will increase every day to China. The US/UK/Netherlands will only increase pressure upon Japan to stop being a nuisance, Japan can’t do anything about this as the US Pacific Fleet is operating around the Philippines always a looming threat. The Japanese are holding for a lack of better words, useless ground in the far east. They will build a buffer area to defend against what can only be described as a Soviet Invasion of Manchuria x1000. The Allies will be directing all of their effort against Germany and Italy, providing a interesting alternate history concept in its own right. After Germany has been dealt with, Japan would face a existential threat against a very angry Stalin.
Cody from Alternate History Hub actually made an episode on this scenario, he believed the Soviets would conquer most of Japan occupied Asia and even invade the home islands. It would certainly be something on the table, taking many years, but the US/UK would most likely interfere in some way. The outcome would be so much worse for Japan. Perhaps she is occupied and a communist government is installed. Perhaps like in our timeline the Americans come in to bolster Japan up for the looming coldwar.
But the question I sought to answer here was, Japan invading the USSR was a dumb idea. The few Japanese commanders who pushed it all the way until August 9th of 1941 simply had to give up because of how illogical it was. I honestly should not have even talked about military matters, this all came down to logistics and resources. You want to know how Japan could have secured itself a better deal in WW2? 1941, the China War is the number one problem Japan can’t solve so they look north or south to acquire the means to solve the China problem? Negotiate a peace with China. That is the lackluster best deal right there.
Sorry if this episode did not match your wildest dreams. But if you want me to do some batshit crazy alternate history stuff, I am more than happy to jump into it and have fun. Again thank all of you guys who joined the patreon, you guys are awesome. Until next time this is the Pacific War channel over and out.