WI: Soviet Invasion of Honshu

[Curiousone]

Assuming the idea doesn't send Truman into orbit?

Assuming that (and since Truman is reputed to have told Stalin that if one "Russian" soldier set foot on the Home Islands he would drop a nuclear weapon down the Kremlin's chimney, that is a big assumption) and accepting that the Japanese make the same dispositions that they made in anticipation of the American invasion, which BTW, were extremely accurate, the Soviets might have ben able to pull it off.

The Soviets apparently had a plan for invading Hokkaido (which makes sense, since it seems like every country on Earth has a plan for invading each other). The weakness of it was that they looked at the crossing from Sakhalin to Hokkaido to be nothing but an bigger version of a river crossing. That is simply not the fact, since it is a 26 mile voyage across some REALLY nasty seas that would swamp anything but true ocean going vessels or off shore fishing boats (even WW II LSTs would be a pain in those waters). There would be no way to provide artillery coverage, and Soviet aircraft had very short legs. The invading forces would be very much on their own.

The good news is that the IJA and IJN had moved just about everything to Kyushu to oppose Olympic. Their deployments, and overall lack of fuel, combined with American destruction of the transport network on both Kyushu and Honshu (such as it was) would mean that the Red Army invaders would have had to face minimal kamikaze attack either by aircraft or boats. They would also have been facing mostly militia, along with some combat ineligibles (mostly damaged vets) with only a few regular formations, all of which would be light on heavy weapons. Once they made it ashore in any sort of numbers, even with light tanks the Red Army should have been able to roll up the Japanese forces. Soviet losses would likely have been far heavier than would be expected given what happened in Manchuria, but Stalin never really gave a damn about losses.

Does Truman still object to Soviet action if the situation is different as per OP, Japanese forces aren't surrendering?

The plan isn't invading just 26 miles across the straits, it's to a port on the West Coast. Previous threads noted how they'd made large (around 10,000men at a time), amphibious invasions across the Sea of Okhotsk to the Kurils, to the South of Sahkalin & over to Korea in August. I don't see why given they'd done that previously they'd be looking at it as river crossing, only larger. Or why they would expect/plan for casualties similar to Manchuria when they'd been spending most of a month fighting for the islands North of Hokkaido. That landing site on Hokkaido is within range of tactical air support.

 

[CalBear]

Does Truman still object to Soviet action if the situation is different as per OP, Japanese forces aren't surrendering?

The plan isn't invading just 26 miles across the straits, it's to a port on the West Coast. Previous threads noted how they'd made large (around 10,000men at a time), amphibious invasions across the Sea of Okhotsk to the Kurils, to the South of Sahkalin & over to Korea in August. I don't see why given they'd done that previously they'd be looking at it as river crossing, only larger. Or why they would expect/plan for casualties similar to Manchuria when they'd been spending most of a month fighting for the islands North of Hokkaido. That landing site on Hokkaido is within range of tactical air support.

Unlike FDR, who Stalin snookered in the last year of his life, Truman despised Stalin and trusted the Soviets as far as he could throw them. He was unalterably opposed to the Soviets getting a piece of the Home Islands, understanding that the maneuvering for position in the post-war world was already underway (he was apparently stunned at the deals that FDR, and to a lesser extent, Churchill, had agreed to with Stalin).

The only way Truman is likely to accept a Soviet force on Hokkaido would be in the case of a repulse of the Olympic landings. Since there is considerable evidence that Truman was leaning away from the landings in favor of simply starving and burning the Japanese to their knees as the casualty estimates continued to skyrocket, this scenario is unlikely. The U.S. had gotten very possessive about the Japanese defeat. Even the British were only given grudging acceptance, and not just by the ever grumbling Admiral King.

Hokkaido was in range of tac air, but the question is what was the loiter time. The YaK-9 had a max range of 420 miles, Il-2 is at 450, MiG-3 is a bit better at 510 (cut these in half for combat radius and subtract about 10-15% for forming up and combat time). As a comparison the P-47 had a combat radius, on internal fuel, of ~400 miles. The key for tactical air is the ability to loiter, wait for targets to present themselves. This is especially the case when you have virtually no artillery to support ground forces.

 

[seraphim74]

Originally posted by CalBear

The only way Truman is likely to accept a Soviet force on Hokkaido would be in the case of a repulse of the Olympic landings. Since there is considerable evidence that Truman was leaning away from the landings in favor of simply starving and burning the Japanese to their knees as the casualty estimates continued to skyrocket, this scenario is unlikely. The U.S. had gotten very possessive about the Japanese defeat. Even the British were only given grudging acceptance, and not just by the ever grumbling Admiral King.

But would the Americans try to stop the Soviets from attacking? And if so, how, if the invasion is launched from Sakhalin?

Hokkaido was in range of tac air, but the question is what was the loiter time. The YaK-9 had a max range of 420 miles, Il-2 is at 450, MiG-3 is a bit better at 510 (cut these in half for combat radius and subtract about 10-15% for forming up and combat time). As a comparison the P-47 had a combat radius, on internal fuel, of ~400 miles. The key for tactical air is the ability to loiter, wait for targets to present themselves. This is especially the case when you have virtually no artillery to support ground forces.

The Soviets had Pe-2 diving bombers with combat range 1000-1300 km (thats ca 600-800 miles - with 1000 kg bombs) and Il-10s attack planes with combat range 800 km (ca 500 miles). And Yak-9D had range of 1350 km (over 800 miles) - enough to protect those planes. So yes, the Soviets did have means to provide air support for invasion of Hokkaido.

 

[CalBear]

Originally posted by CalBear
But would the Americans try to stop the Soviets from attacking? And if so, how, if the invasion is launched from Sakhalin?


The Soviets had Pe-2 diving bombers with combat range 1000-1300 km (thats ca 600-800 miles - with 1000 kg bombs) and Il-10s attack planes with combat range 800 km (ca 500 miles). And Yak-9D had range of 1350 km (over 800 miles) - enough to protect those planes. So yes, the Soviets did have means to provide air support for invasion of Hokkaido.

Combat range =/= combat radius.

The P-47 had a combat range of 800 miles with up to 1,200kg (2,500 pounds) of bombs/rockets/ammo, but it could effectively operate out to a maximum of 350 miles (800/2 and around 10% subtracted for forming up and full throttle combat maneuvering) on internal fuel. It could add roughly 100 miles to that with drop tanks which still left it 200 miles short of Berlin. This same sort of calculation is needed for every other aircraft.

 

[Curiousone]

Combat range =/= combat radius.

The P-47 had a combat range of 800 miles with up to 1,200kg (2,500 pounds) of bombs/rockets/ammo, but it could effectively operate out to a maximum of 350 miles (800/2 and around 10% subtracted for forming up and full throttle combat maneuvering) on internal fuel. It could add roughly 100 miles to that with drop tanks which still left it 200 miles short of Berlin. This same sort of calculation is needed for every other aircraft.

The tip of Sahkalin to Rumoi, Hokkaido is 140 miles.

http://www.daftlogic.com/projects-google-maps-distance-calculator.htm

There and back with 15% to spare for forming up & loitering while hunting for targets is around 322 fuel miles used out of 420 available for the shortest ranged aircraft mentioned, the Yak-9D.

Is Truman prepared to order U.S forces to fire on Soviet forces? How on Earth is he going to spin starting a war with what the public's been led to believe is a great Ally fighting a terrible Foe while that Foe is still fighting? Every Liberal & Socialist is going to be raising the roof about what a backstabbing war mongerer he is.. 'as if WW2 wasn't enough, he wants WW3!'.

The range from the inland transport hub leading off from Rumoi, Fukugawa to Tokyo is 570 miles. The range from Miazaki, a town on the East coast of the southern third of Kyushu is 540 miles (yes there's far more than 30 miles of Hokkaido south of Fukugawa). If the reasoning behind Olympic is to gain airbases from which to support Coronet, why are the Americans pressuring the Russians not to invade Hokkaido if the Japanese haven't surrendered instead of just pressuring them for airbases and saving themselves the casualties & trouble of Olympic? They'll still have the Naval superiority after the war to dictate access to Japan if need be.

I suspect the American response so long as Japan is holding out might be to sea mine any further likely Soviet invasion areas (if it's worth likely losing the airbases, if), then look more closely at invading via Northern Honshu (Mutsu or Sendai are listed as possibles http://en.wikipedia.org/wiki/Operation_Downfall#Alternative_targets) to cut them off from advancing further.

The Soviets said they'd do a lot of things & didn't do them before the Cold War began in earnest. They said they'd allow W/Allies to see that they really were preparing for the Manchurian invasion as promised but didn't. Events rolled on with the W/Allies & Soviets kept working together.

 

[CalBear]

The tip of Sahkalin to Rumoi, Hokkaido is 140 miles.

http://www.daftlogic.com/projects-google-maps-distance-calculator.htm

There and back with 15% to spare for forming up & loitering while hunting for targets is around 322 fuel miles used out of 420 available for the shortest ranged aircraft mentioned, the Yak-9D.

Is Truman prepared to order U.S forces to fire on Soviet forces? How on Earth is he going to spin starting a war with what the public's been led to believe is a great Ally fighting a terrible Foe while that Foe is still fighting? Every Liberal & Socialist is going to be raising the roof about what a backstabbing war mongerer he is.. 'as if WW2 wasn't enough, he wants WW3!'.

The range from the inland transport hub leading off from Rumoi, Fukugawa to Tokyo is 570 miles. The range from Miazaki, a town on the East coast of the southern third of Kyushu is 540 miles (yes there's far more than 30 miles of Hokkaido south of Fukugawa). If the reasoning behind Olympic is to gain airbases from which to support Coronet, why are the Americans pressuring the Russians not to invade Hokkaido if the Japanese haven't surrendered instead of just pressuring them for airbases and saving themselves the casualties & trouble of Olympic? They'll still have the Naval superiority after the war to dictate access to Japan if need be.

I suspect the American response so long as Japan is holding out might be to sea mine any further likely Soviet invasion areas (if it's worth likely losing the airbases, if), then look more closely at invading via Northern Honshu (Mutsu or Sendai are listed as possibles http://en.wikipedia.org/wiki/Operation_Downfall#Alternative_targets) to cut them off from advancing further.

The Soviets said they'd do a lot of things & didn't do them before the Cold War began in earnest. They said they'd allow W/Allies to see that they really were preparing for the Manchurian invasion as promised but didn't. Events rolled on with the W/Allies & Soviets kept working together.

He doesn't really have to fire on Soviet units. all he needs to do is increase the already existing mining operations around Hokkaido. The U.S. had effectively isolated the Japanese Home Islands with what was/is the most effective mining operation ever seen. With the bases on Okinawa the B-29 force that effectively closed the Sea of Japan to everything bigger than a fishing boat, could readily operate far enough north to supplement the already deployed and regularly renewed mine array deployed by U.S. submarines. (One of the ignored stories of the Pacific War is the enormous mine clearing operation that followed the Japanese surrender. The last major USN vessel officially listed as lost in WW II was a minesweeper off Japan.)

This being said, Truman had already shown serious fangs to the Soviets. The USSR and the WAllies had already began to fall out even before the Potsdam Conference. After directly meeting with Stalin Truman was not about to give an inch. By July 1945 the USN owned the waters around Japan. Literally nothing longer than 25 feet survived in those waters unless the U.S. decided to allow it (it is worth remembering that the U.S. was already strafing oxcarts on both Kyushu and Honshu to deny the Japanese military any source of supply). Anything in the Sea of Japan that could be used to transfer troops from the Asian mainland was sunk on sight.

One of the things that is rarely appreciated about Stalin is that he was very, very sensible. He could calculate forces with the best of them and the force correlation in the Pacific Ocean was not exactly in the Soviets favor. The risk/reward of defying U.S. interests in the Home Islands compared to the still fluid situation in Europe would never have justified any unilateral move toward Hokkaido.

 

[The Red]

I know this is probably out of the question, but if the mining is too heavy to risk crossing the Tsugaru Strait by sea, what about an airbourne landing? The 4th airbourne corps could establish themselves on the northern tip and try to secure an airfield to allow supplies to be flown in, possibly with the aid of some T-27's, which were osbolete in the European theatre but would able to go toe to toe with the generally light Japanese tanks, if they encounter any. Advancing very far south would likely be out of the question, but the act of the Soviets having a presence on Honshu might increase their hand in negotiating the post-war occupation.

 

[seraphim74]

Originally posted by CalBear

Combat range =/= combat radius. The P-47 had a combat range of 800 miles with up to 1,200kg (2,500 pounds) of bombs/rockets/ammo, but it could effectively operate out to a maximum of 350 miles (800/2 and around 10% subtracted for forming up and full throttle combat maneuvering) on internal fuel. It could add roughly 100 miles to that with drop tanks which still left it 200 miles short of Berlin. This same sort of calculation is needed for every other aircraft.

I'm not sure I understand. I gave you examples of Soviet airplanes with combat range comparable to the range of P-47, which you seem to consider a plane capable of providing necessary air support. While combat range does not equal combat radius it seems logical to me that the bigger the range the bigger is combat radius (radius = x/2 + 10%x, with x being the combat range). As Curiousone noticed, the Soviet planes were perfectly capable to reach targets on Hokkaido from airfields on Sakhalin with quite a time to spare. Pe-2s had comparable range to P-47; let's say 400 miles there and back (2x200 miles) and it still leaves Pe-2 with equivalent of at least 200 miles over the target area (probably more); the same of for Yak-9D; by the same count Il-10s would have about equivalent of 100 miles over the target area (20% of its capability).
Assuming Pe-2 flies 300 mph (its maximum speed was 360 mph), 200 miles of range at that speed will give it about 40 minutes over the target area. Il-10's cruising speed was ca 200 mph, which gives it about 30 minutes over the target area - assuming they have not their target already selected. If so, they have a lot of time to hit it and go back home. If not, they can wait for a call from the ground forces. So they might come to the area without any specific mission, except "you will bomb what comrades from the ground will tell you to bomb". In battle targets might change quickly, so it might be useful to have a bomber (or a squadron of them) "waiting nearby" and capable to attack the target only minutes after receiving orders.

 

[Curiousone]

I know this is probably out of the question, but if the mining is too heavy to risk crossing the Tsugaru Strait by sea, what about an airbourne landing? The 4th airbourne corps could establish themselves on the northern tip and try to secure an airfield to allow supplies to be flown in, possibly with the aid of some T-27's, which were osbolete in the European theatre but would able to go toe to toe with the generally light Japanese tanks, if they encounter any. Advancing very far south would likely be out of the question, but the act of the Soviets having a presence on Honshu might increase their hand in negotiating the post-war occupation.

Tracked down more details as to the invasion as planned OTL.

'The commanders of the First and Second Far Eastern Fronts, the Pacific Fleet, and the Air Force were ordered to launch an airborne operation in the port and city of Rumoi and to make the airbase available by August 23 for the occupation of the Northern part of Hokkaido.'

... further more 2-3 infantry divisions by sea in 2-3 echelons ...
(Original plan - take Rumoi, move to take the Northern Half of Hokkaido stretching from Rumoi to Kushiro to Wakkani. If strong resistance is met, take the whole Island).

... 'Why did it take Stalin a full four days to reply to Truman's message?' ...
... 'Even after he(Stalin) received Truman's letter he let his military proceed with the plan to invade Hokkaido. He was weighing the pro's & con's of going ahead with the Hokkaido invasion plan.' ...

http://books.google.com.au/books?id...gK#v=onepage&q=rumoi hokkaido landing&f=false

If it's a matter that in OTL was in the balance, something Stalin was chewing over, still considering doing even after Japan had surrendered & Truman had warned him off, I'm not so sure it's definite he still doesn't do it if Japan's still fighting by late August for whatever reason (Army Coup etc).

 

[The Red]

If it's a matter that in OTL was in the balance, something Stalin was chewing over, still considering doing even after Japan had surrendered & Truman had warned him off, I'm not so sure it's definite he still doesn't do it if Japan's still fighting by late August for whatever reason (Army Coup etc).

This might be worth a collaborative TL if you're up for it? Fanatical army coup takes over, the Emperor is somehow incapacitated, and the October typhoon is used as 'proof' of divine providence. The Soviet invasion of Hokkaido proceeds ahead in late August with the Americans invading Kyushu in November?

 

[Curiousone]

This might be worth a collaborative TL if you're up for it? Fanatical army coup takes over, the Emperor is somehow incapacitated, and the October typhoon is used as 'proof' of divine providence. The Soviet invasion of Hokkaido proceeds ahead in late August with the Americans invading Kyushu in November?

Ha I'm interested to read what others have to say, am kind of in the exam portion of my semester at the moment so have to cram, can't properly contribute to a whole TL unfortunately.
Olympic going ahead on Kyushu in November despite the intelligence being gathered (the OTL unconvinced McArthur somehow gets his way?) seems to be the way for the greatest Soviet position vis-a-vis Japan post war. W/Allies landings being diverted to Sendai or Onimoto as had been suggested could make for an interesting race down the coast/race to cut the other guys advances off if the Soviets had already landed on the N/West coast of Honshu.

Reading further down into that last link I had under google books,
"Racing the Enemy: Stalin, Truman, and the Surrender of Japan By Tsuyoshi Hasegawa"
The part where he's getting into counter-factuals.

P.296: "The United States might have resisted the Soviet Operation against Hokkaido, but given the Soviets' militaries high strength, and given the enormous casualty figures the American high command had estimated for Olympic, the United States might have conceded the division of Hokkaido as Stalin had envisaged. Even if the United States had succeeded in resisting Stalins pressure, Soviet military conquests in the rest of the Far East might have led Truman to concede some degree of Soviet participation in Japan's postwar occupation."

 

[mlp]

Ha I'm interested to read what others have to say, am kind of in the exam portion of my semester at the moment so have to cram, can't properly contribute to a whole TL unfortunately.
Olympic going ahead on Kyushu in November despite the intelligence being gathered (the OTL unconvinced McArthur somehow gets his way?) seems to be the way for the greatest Soviet position vis-a-vis Japan post war. W/Allies landings being diverted to Sendai or Onimoto as had been suggested could make for an interesting race down the coast/race to cut the other guys advances off if the Soviets had already landed on the N/West coast of Honshu.

Reading further down into that last link I had under google books,
"Racing the Enemy: Stalin, Truman, and the Surrender of Japan By Tsuyoshi Hasegawa"
The part where he's getting into counter-factuals.

P.296: "The United States might have resisted the Soviet Operation against Hokkaido, but given the Soviets' militaries high strength, and given the enormous casualty figures the American high command had estimated for Olympic, the United States might have conceded the division of Hokkaido as Stalin had envisaged. Even if the United States had succeeded in resisting Stalins pressure, Soviet military conquests in the rest of the Far East might have led Truman to concede some degree of Soviet participation in Japan's postwar occupation."

Hm. so we've reached a consensus that the Soviets will be able to take Hokkaido, but not northern Honshu? That's still pretty awesome, although I do have a feeling that if the war drags onto 1946 the US will "call" for Soviet help. As was said in the article I read (the Foreign Policy one on OP), the Japanese "knew Soviet advance would be very fast, compared to the Americans" since all forces were concentrated against a possible US attack, not a Soviet attack.

 

[Curiousone]

Tracked down the amphibious portion of the Invasion plan.

Apparently it got as far as Submarine reconnaissance of Roumi, L-12 & L-9 were on station on the 21st August.

ДОНЕСЕНИЕ КОМАНДУЮЩЕГО ТИХООКЕАНСКИМ ФЛОТОМ
ГЛАВНОКОМАНДУЮЩЕМУ СОВЕТСКИМИ ВОЙСКАМИ НА ДАЛЬНЕМ
ВОСТОКЕ С ИЗЛОЖЕНИЕМ ПЛАНА ОПЕРАЦИИ ПО ПЕРЕВОЗКЕ
87-го СТРЕЛКОВОГО КОРПУСА НА о. ХОККАЙДО И ЮЖНЫЕ о-ва
КУРИЛЬСКОЙ ГРЯДЫ

19 августа 1945 г.
Доношу план операции по перевозке 87 ск на о. Хоккайдо и южную часть о-вов Курильской гряды.
1. Операция проводится в три этапа:
а) первый этап — перевозка одной сд в порт Румои;
б) второй этап — перевозка одной сд в порт Румои;
в) третий этап — перевозка одной сд на острова Курильской гряды через о. Хоккайдо.
2. Выполнение операции:
а) сосредоточить на аэродромах Владимиро-Ольгинской ВМБ два полка ДБ-3, полк Як-9 и 20 Як-9ю;
б) развернуть четыре позиции подлодок со стороны Сангарского и Лаперузо-ва* проливов; задача — разведка и уничтожение боевых кораблей противника. Всего 4 подлодки;
в) вести разведку портов и военно-морских баз южной части Сахалина, о. Хоккайдо, Сангарского пролива и подходов к западному побережью Хоккайдо начиная с 19.8.45 г. с целью выявления нахождения боевых кораблей.
3. Перевозку войск осуществить: первый бросок — в составе одного бмп, одного сп на 6 десантных судах в охранении 4 эсминцев и 6 торпедных катеров. Эсминцы в случае противодействия используются как корабли артиллерийской поддержки, торпедные катера в благоприятной обстановке используются как высадочные средства первого броска. Основные силы сд перевозятся на шести транспортах в охранении четырех фрегатов, четырех тральщиков и четырех больших охотников. Первый бросок выходит с расчетом быть в районе высадки— порт Румои — на 2 часа раньше подхода основных сил сд.
4. Обеспечение: два эсминца и шесть торпедных катеров «Владимир». Истребительная авиация прикрывает всех на переходе, бомбардировочная и торпедоносная авиация в момент подхода кораблей к Румои занимает зону ожидания над портом.
Удар по порту производить только по сигналу командира высадки. Командует высадкой контр-адмирал Святов. Общее руководство операцией оставляю за собой.
Готовность кораблей к посадке первой дивизии в 12.00 19.8.45 г. Выход — 20.00 21.8.45 г.
Высадка — 05.00 24.8.45 г., посадка остальных — по мере возвращения транспортов.
Прошу утвердить.
Командующий ТОФ ЮМАШЕВ
Член Военного совета ТОФ ЗАХАРОВ Печ. по: ЦАМО РФ. Ф. 66. Оп. 178499 Д. I. Л. 442-443. Копия.

REPORT of the Pacific Fleet
Commander of Soviet forces in the Far
EAST BY THE PLAN OF OPERATIONS FOR THE TRANSPORT
87th Rifles Corps of . Hokkaido and South Islands
KURILE RIDGE

August 19, 1945
Donoshu plan in the carriage of 87 sk on about. Hokkaido and the southern part of the Kuril Islands .
1. The operation is performed in three steps:
a) The first stage - the transport of one SD in Port DIA ;
b ) The second stage - the transport of one SD in Port DIA ;
c) The third stage - the transport of a Rifle on the Kuril Islands by a. Hokkaido .
2 . The operation :
a) focus on the airfields of the Vladimir- Olginskaya HMB two regiments of the DB-3 , a regiment of the Yak -9 and Yak- 20 9yu ;
b) deploy four positions submarines from Tsugaru and La Perouse Straits Islands * ; task - exploration and destruction of enemy warships . Only 4 subs ;
c) to explore for ports and naval bases in the southern part of Sakhalin , Fr. Hokkaido, the Tsugaru Strait and the approaches to the west coast of Hokkaido since 8/19/45 , with the aim of finding identifying warships.
3 . Transport of troops to carry out : the first shot - one in the BMP , a joint venture by 6 amphibious ships escorted by four destroyers and six torpedo boats. Destroyers in the case of anti- used as fire support ships , torpedo boats in a supportive environment are used as landing craft first throw . The main forces Rifle carried on six transports escorted by four frigates, four minesweepers and four great hunters. The first roll out with the expectation to be in the landing area port DIA - 2 hours before the main forces cq .
4 . Providing two destroyers and six torpedo boats "Vladimir" . Fighter aircraft covers all of the junction , bombers and torpedo aircraft at the time of the approach of ships to the DIA is the waiting area of the port .
A blow to the port only produce a signal commanding the landing . Commanded by Rear Admiral landing the Saints. Overall operation reserve.
Willingness to board the ships of the First Division at 12.00 , the output 08/19/45 - 08/21/45 20.00 g
The landing - 08/24/45 05.00 g , planting the rest - at least the return of the transports .
I ask to approve .
Commander of the Pacific Fleet Yumashev
A member of the Military Council of the Pacific Fleet ZAKhAROV Pech. by: TsAMO Russia. F. 66. Op . 178499 D. I. L. 442-443 . A copy of the .

 

[NoOneFamous]

What was the Soviet amphibious capability?

 

[Curiousone]

What was the Soviet amphibious capability?

http://en.wikipedia.org/wiki/Project_Hula
Able to land at most a division a day, ability to support about three divisions in total in the Pacific.

 

[CalBear]

Originally posted by CalBear
I'm not sure I understand. I gave you examples of Soviet airplanes with combat range comparable to the range of P-47, which you seem to consider a plane capable of providing necessary air support. While combat range does not equal combat radius it seems logical to me that the bigger the range the bigger is combat radius (radius = x/2 + 10%x, with x being the combat range). As Curiousone noticed, the Soviet planes were perfectly capable to reach targets on Hokkaido from airfields on Sakhalin with quite a time to spare. Pe-2s had comparable range to P-47; let's say 400 miles there and back (2x200 miles) and it still leaves Pe-2 with equivalent of at least 200 miles over the target area (probably more); the same of for Yak-9D; by the same count Il-10s would have about equivalent of 100 miles over the target area (20% of its capability).
Assuming Pe-2 flies 300 mph (its maximum speed was 360 mph), 200 miles of range at that speed will give it about 40 minutes over the target area. Il-10's cruising speed was ca 200 mph, which gives it about 30 minutes over the target area - assuming they have not their target already selected. If so, they have a lot of time to hit it and go back home. If not, they can wait for a call from the ground forces. So they might come to the area without any specific mission, except "you will bomb what comrades from the ground will tell you to bomb". In battle targets might change quickly, so it might be useful to have a bomber (or a squadron of them) "waiting nearby" and capable to attack the target only minutes after receiving orders.

No, I gave you a direct comparative. The P-47 had a COMBAT RANGE of 800 miles, the bF-109 had a combat range of 521 miles, the P-51 had a combat range of 950 (all of these are on internal fuel). The P-51 with drop tanks had a combat range of 1,650 miles. This does not mean it could fly out 1,650 miles on an escort mission and return (if that were the case it would have a combat range greater than the B-29 which could reach out 1,600 miles and return with a 10,000 pound bomb load). The formula for combat radius is (combat range/2)*.9 the result for the P-51D w/tanks is 745 miles

It means the P-51 (w/tanks) could take off, form up into a formation, fly ~700 miles out from base in high economy cruise, engage in air combat for roughly 20 minutes, and make it home with enough fuel to make at least two landing attempts. That is why you need to discuss combat radius not range. Range is only useful if you are taking off at one point, overflying your target, and landing at a different location (the USAAF occasionally did this with bomber mission flying out of the UK and landing at Allied air bases in Italy).

An aircraft like the Yak-9D had a maximum range of 2,285km (1,400mi) in absolutely clean unladen status with drop tanks, 845 miles w/o tanks. This is the ferry range. The P-51D had a ferry range of 2,300 miles, this means the combat range of the P-51 was 71% of its maximum range, and its combat radius was~30% of maximum range. If one uses the Mustang as a guide (which actually rather generous since the Mustang was a remarkably efficient air frame/engine combination) you will get a combat radius of 420 miles for the Yak-9D (which makes it, by far, the longest range Soviet fighter of the war) and a loiter time of around 30 minutes from the time it reaches the beach, more likely 20-25 by the time it is actually orbiting (this is just about what the P-47 managed over Normandy which was flown from similar ranges). The quick and dirty method of figuring out loiter time is to take the excess range of an aircraft, in this case the Yak and divide that by the cruise speed of the aircraft. In the case of the Yak this is 200/225 or 53 minutes Of course the Yak-9D was pure fighter, and a rather poorly armed one (the aircraft had one 20mm cannon and one 12.7mm (.51 cal) machine gun, with very limited ground attack capacity.

A better comparative is the Il-2 which comes out with with a combat radius of 225 miles. This leave around the ground attack aircraft with a ten minute loiter (I used 25 miles for the excess range since using the actual data of 200 out and 200 back would leave basically nothing, since the Il-2 combat radius is 202 miles, rather than come back with this result I used the ~500 mile range of the Il-10) Ten minute loiter is effectively zero unless you have a target already selected before the aircraft goes feet dry.

The figures for the Pe-2 are somewhat better. Using a cruise speed of 300 mph and the 200 mile out & 200 back you come back with a very reasonable 24 minutes of loiter. I am unsure of the effectiveness of the Pe-2 in the CAS role. The Soviets seem to have used it in the level bomber role, an attack methodology that is ill suited to the close support mission.

 

[katchen]

living until So the real POD for Russia getting an occupation zone in Hokkaido and North Honshu is Roosevelt surviving at least until after Japan surrenders. Because Roosevelt seemed inclined to grant Russia a say in the occupation of Japan. (At least the proposal for Four Power occuaption of Japan was devised on Roosevelt's watch.
For whatever reason, but what Truman saw as Stalin's perfidy, Roosevelt behaved as if he saw as legitimate needs and demands on Russia's part. In some ways, the Roosevelt Adinistration was quite apolegetic for Stalin's Soviet Union. It was FDR after all, who first recognized the USSR as soon as he took office in 1933. And later refused to protest when Stalin caused the artificial famine that killed as many as 10 million Ukranians during the 1930s forced collectivization despite the Democrats having a large constituency amongst Ukranian Americans.
So we might have a very different TL if Roosevelt had lived to finish out his fourth term. In that TL,Japan might well have been divided like Germany--and like Germany, Roosevelt might well have justified it as preventing Japan from ever rising up again. The Republicans mifht not have captured Congress in 1946 with Roosevelt campaigning for Democrats. And Roosevelt might have been able to make HIS veto of Taft Hartley Act stick. Which might well have delayed the onset of the Cold War and might have made the Cold War a lot more partisan but it would have made FDR a lightining rod for criticism of the Left and of American foreign policy with regard to Communism.


W

 

[Chris S]

Pretty much any analysis of how Truman would act to stop the Soviets from somehow invading must and can only be based on how Truman reacted to the Soviets after the Japanese indicated they were going to surrender over the period of August 14/15. At that point Truman (with the support of Macarthur) rejected proposals by his own JCS for dividing Japan into occupation zones with the Soviets getting Hokkaido and northern Honshu. Prior to that Truman did not oppose Soviet involvement even if after a while he thought it might become unnecessary. It's unlikely that Truman would go so far as to prevent a Soviet landing on Hokkaido with mines if the situation existed wherein the Soviets couls invade since it would mean the Japanese hadn't surrendered even after the atomic bombings. That's as ASB as Churchill refusing to ally with the Soviets after June 1941.

 

[ObssesedNuker]

For the practical of details of a Soviet landing operation against Hokkaido, look at this post and its secondary links. Note that this post also addresses issues like Japanese response and the kamikaze threat.

I also do not believe that Truman would nix a Soviet landing on Hokkaido assuming Japan has not yet surrendered for three reasons: firstly because a successful Soviet invasion of the home islands would be an immense step forward in compelling the Japanese to surrender, secondly because the nature of the Soviet landing means he isn't likely to find out about it until after the invasion has already occurred, and thirdly because the Soviet Union is still viewed as "our good ally against the insidious Axis" by the US public and they wouldn't stand for the blatantly aggressive moves the US would have to take to stop a Soviet landing.

Also, any landing on Hokkaido would likely come from Vladivostock, like the landings on the Kuriles. Note that the Rumoi prefecture is closer to Vladivostock then the Kuriles?

Now as for continuing onto Honshu: I doubt it. A successful invasion of Hokkaido alone would likely trigger a Japanese surrender, to say nothing of the months and months the Soviets would require to secure the island and establish the necessary logistics to move onto to Honshu. And a direct landing on Honshu, by-passing Hokkaido, is out of the question given Soviet amphibious and sea lift capabilities.

 

[Seleucus]

This might be worth a collaborative TL if you're up for it? Fanatical army coup takes over, the Emperor is somehow incapacitated, and the October typhoon is used as 'proof' of divine providence. The Soviet invasion of Hokkaido proceeds ahead in late August with the Americans invading Kyushu in November?

I'd be really interested in reading that timeline. Some possible considerations:

- A successful coup would probably prolong the war enough for the Nationalists to retake much of Japanese-held south/east China. This would greatly help their credibility and authority in the postwar outcome.

- Tactical atomic bombing would almost certainly be used in the Kyushu invasion, resulting in radiation poisoning of numerous American GIs (as radiation was not well understood) - in the long term, this would probably stigmatize the postwar reputation of nuclear power.