A proper attack on Pearl Harbor

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Peter89
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A proper attack on Pearl Harbor

Post by Peter89 » 05 Jun 2020 13:02

Hello guys,


in the past few weeks of quarantine, I had the pleasure to read a few bits about the decision making process behind the Japanese attack on Pearl Harbor.

The Japanese strategy was built upon many questionable premises, however, I am interested in whether it was utterly false or not.

The main idea was that the USN Pacific fleet had to be neutralized by one, critical blow, allowing them to establish an economic sphere, the GEACPS.
Gordon Prange believed that Nagumo’s failure to “pulverize the Pearl Harbor base” and “to seek out and sink America’s carriers” was Japan’s “first and probably greatest strategic error of the entire Pacific conflict.”101 The destruction of Pearl Harbor or the invasion and occupation of the Hawaiian Islands would have compelled the Navy to operate from the American West Coast, adding another 3,000 miles of distance to be surmounted before grappling with the Japanese in the Central and Southwestern Pacific. After the war, Minoru Genda, the brilliant Japanese naval aviator who planned the details of the attack on Pearl Harbor, lamented the Japanese failure to invade Hawaii, which he blamed on the IJA’s preoccupation with eventual war against the Soviet Union and unwillingness to release (from Manchuria) the divisions necessary to take Hawaii. “After the attack on Pearl Harbor,” he said, “we could have taken Honolulu pretty easily. This would have deprived the American Navy of its best island base in the Pacific [and] would have cut the lifeline to Australia, and that country might have fallen to us like a ripe plum.” Japanese possession of Hawaii and Australia would have deprived the United States of the indispensable base from which to challenge Japanese control of Southeast Asia.
However, they never really prepared to learn lessons from the British. They planned the attack much like the British neutralized the Italian fleet at the Battle of Taranto. However, when Lt. Commander Takeshi Naito, the Japanese naval attaché in Berlin visited the venue immediately after the attack to observe the damage, he might have been astonished by the sight of the sunken battleships. However, when a Japanese military delegation toured Italy half a year later (May 18 1941 - June 8 1941), and seen the Littorio as a flagship of the Italian Navy, they must have known that the damage was not critical. The two battleships Caio Duilio and Littorio were already back in service, and the Italians already started to pump out water of the hull of Conte di Cavour, refloating the damaged battleship on 9th of June 1941. It must be noted that the refloating efforts for Conte di Cavour were delayed by the lack of resources, and not by the lack of technology (something the US will never face in PH).

Image
source: Angus Konstam: Taranto 1940: The Fleet Air Arm’s precursor to Pearl Harbor, p. 91

Also, the Japanese indeed were aware that Pearl Harbor had shallow water (~13m, 45ft), even more shallow than Taranto (20-22m, 66-72 ft) making refloating operations much more easier. The Japanese decision makers must have known that a simple attack by airplanes will not result the destruction of the USN naval power in the Pacific.

The only way to destroy a ship in a shallow harbour was to detonate its magazines, which only happened with USS Arizona.
Yet Yamamoto’s objective in the Pearl Harbor attack was limited: to knock out the U.S. Pacific Fleet for at least 6 months so that Japan could conquer Southeast Asia without American naval interference. Pearl Harbor was essentially a flanking raid in support of the main event, which was Tokyo’s southward move against Malaya, Singapore, the Philippines, and the Dutch East Indies. The possibility of occupying Hawaii was never seriously considered by either Yamamoto or the IJN’s general staff.
source: Jeffrey Record: JAPAN’S DECISION FOR WAR IN 1941:SOME ENDURING LESSONS

However, even that limited operation went wrong because the aircraft carriers, the new means to project navel power in the Pacific, were en route at the time of the attack.
On 7 December 1941, the three Pacific Fleet aircraft carriers were USS Enterprise (CV-6), USS Lexington (CV-2), and USS Saratoga(CV-3).

Enterprise: On 28 November 1941, Admiral Husband E. Kimmel sent TF-8, consisting of Enterprise, the heavy cruisers Northampton(CA-26), Chester (CA-27), and Salt Lake City (CA-24) and nine destroyers under Vice Admiral William F. Halsey, Jr., to ferry 12 Grumman F4F-3 Wildcats of Marine Fighting Squadron (VMF) 211 to Wake Island. Upon completion of the mission on 4 December, TF-8 set course to return to Pearl Harbor. Dawn on 7 December 1941 found TF-8 about 215 miles west of Oahu.

Lexington: On 5 December 1941, TF-12, formed around Lexington, under the command of Rear Admiral John H. Newton, sailed from Pearl to ferry 18 Vought SB2U-3 Vindicators of Marine Scout Bombing Squadron 231 to Midway Island. Dawn on 7 December 1941 found Lexington, heavy cruisers Chicago (CA-29), Portland (CA-33), and Astoria (CA-34), and five destroyers about 500 miles southeast of Midway. The outbreak of hostilities resulted in cancellation of the mission and VMSB-231 was retained on board [they would ultimately fly to Midway from Hickam Field on 21 December].

Saratoga: The Saratoga, having recently completed an overhaul at the Puget Sound Navy Yard, Bremerton, Washington, reached NAS San Diego [North Island] late in the forenoon watch on 7 December. She was to embark her air group, as well as Marine Fighting Squadron (VMF) 221 and a cargo of miscellaneous airplanes to ferry to Pearl Harbor.

Yorktown (CV-5), Ranger (CV-4) and Wasp (CV-7), along with the aircraft escort vessel Long Island (AVG-1), were in the Atlantic Fleet; Hornet (CV-8), commissioned in late October 1941, had yet to carry out her shakedown. Yorktown would be the first Atlantic Fleet carrier to be transferred to the Pacific, sailing on 16 December 1941.
source: https://www.history.navy.mil/research/l ... tions.html

The naval military doctrine, the Kantai Kessen could only be achieved if the US capability to wage a naval war was utterly destroyed. We can safely conclude that only the carriers Enterprise, Lexington and Saratoga were in the reach of the Japanese attack on Pearl Harbor (the Langley, already converted to a seaplane tender, was in Cavite, Philippines). So even if we presume the best scenario for a hypothetical attack on Pearl Harbor, we can calculate with the destruction of these three carriers (if the all-out attack commenced when all of them were at anchor in Pearl Harbor).

Also, the Japanese must have been aware that naval warfare became combined arms operation, where the quality and training of the airforce had a crucial role in success. The inexperienced naval aviators tended to target their own ships (as was seen in the disastrous Operation Wikinger, in the Battle of Calabria and at chase of the Bismarck), and were prone to get rid of their bombs and torpedoes instead of a proper attack. So if the Japanese were about to exploit their Kantai Kessen, they must destroy the experienced naval aviator units and sustain little damage to their own, well into 1942.

They also might have been aware of the "glass canon" nature of aircraft carriers. So far, the Germans sank HMS Courageous (17 September 1939), HMS Glorious (8 June 1940), and HMS Ark Royal (14 November 1941), and all of that with 1-2 torpedo(es) or 1-2 high caliber shells. So they might have been aware that their best and only chance to achieve a total, decisive victory was to attack an enemy that is not ready to attack back.


Now let's take a quick look into the future.

Given the fact that the later carrier battles were fought on more or less equal terms, it shows that the Japanese failed to concentrate their forces because the initial blow wasn't critical.

The Japanese aircraft carrier building program had the following results after the Pearl Harbor attack and before 1943:
  • Jun'yō (42 planes) 3 May 1942
    Hiyō (53 planes) 31 July 1942
    Ryūhō (31 planes) 30 November 1942
In addition, they had:
  • Ryūjō (48 planes) 9 May 1933
    Zuihō (30 planes) 27 December 1940
    Shōhō (30 planes) 30 November 1941
And the Kido Butai:
  • Akagi 66 planes (+25 reserve)
    Kaga 72 planes (+ 18 in storage)
    Soryu 63 planes (+9 reserve)
    Hiryu 64 planes (+9 spares)
    Shokaku 72 planes (+12 spares)
    Zuikaku 72 planes (+12 spares)
Altogether, 6 fleet carriers and 6 light carriers with about 666 planes, of which 3 light carriers servicing 126 planes were added between the Pearl Harbor attack and the beginning of 1943. (Not counting the training carrier Hosho.)

In OTL, 4 fleet carriers and two light carriers sunk before 1943, namely: Akagi (5 June 1942), Kaga (4 June 1942), Soryu (4 June 1942), Hiryu (5 June 1942), Shoho (7 May 1942) and Ryujo (10 November 1942).

The USN aircraft carriers started to arrive in numbers in 1943 (7 fleet carriers* and 9 light carriers, compared to 0 new Japanese carriers), but before that, they had the following capacities:
  • USS Lexington (CV-2) 78 planes
    USS Saratoga (CV-3) 78 planes
    USS Ranger (CV-4) 76-86 planes, but never took part in operations in the Pacific
    USS Yorktown (CV-5) 90 planes
    USS Enterprise (CV-6) 90 planes
    USS Wasp (CV-7) 100 planes
    USS Hornet (CV-8) 72 planes
Altogether, 7 fleet carriers with about 594 planes, for two oceans.

In OTL, 4 fleet carriers and a seaplane tender sunk before 1943, namely: the Langley (8 May 1942), the Lexington (24 June 1942), the Yorktown (7 June 1942), the Wasp (15 September 1942) and the Hornet (26 October 1942).


Here comes my theory, which I'd like to discuss with you guys.

What if the Japanese decision makers decide to launch an all-out attack on Pearl Harbor and succeed in destroying the better part of the US Pacific fleet?


So they destroy Lexington and the Enterprise (and maybe Saratoga), take the Hawaii Islands and thus deny the Americans to repair their damaged ships and push the American base of operations 3000 miles eastwards.

How would it affect the Pacific war?

Could the Japanese maintain a quantitative edge until 1943, and fight roughly on equal terms until 1944?

The USN aircraft carriers started to arrive in numbers in 1943 (7 fleet carriers* and 9 light carriers, compared to 0 new Japanese carriers), and they built 7 fleet carriers in 1944. In the meanwhile, the Japanese could reinforce themselves only with 4 fleet carriers and 2 light carriers, all of them starting their services in 1944.

Could they actually fight effectively in 1944?

Or in other words, could the Japanese grand strategy work (until the A-bomb was deployed) if they execute their Pearl Harbor operation perfectly?


*technically, the USS Essex was commissioned on 31th December 1942

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T. A. Gardner
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Re: A proper attack on Pearl Harbor

Post by T. A. Gardner » 05 Jun 2020 15:40

This has been beaten to death here, probably only second to Seelöwe. Here's an example of an old thread on invading Oahu:

viewtopic.php?f=11&t=159159&hilit=oahu

For Japan to even have a slight chance of success invading Hawaii, they have to give up invading the Philippines or Malaya, possibly even both. They would need the shipping and manpower to land in Hawaii and they have no other alternate source for it. They also still absolutely need the DEI for resources so that's out. It's also vastly harder for them to keep it a surprise move due to the no massive size of the fleet needed and the fact it takes about twice as long to cross the Pacific.

Even then, the chances of success aren't great. The US Army alone has about 40,000 men in Hawaii total. The coast defenses of Oahu are brutally massive. They aren't like the British ones at Singapore either. They can act in all-around defense in large part and cover all of the accessible beaches with massive amounts of firepower. They would also be difficult or impossible to take out for the Japanese just as they were in the Philippines. You might note, they were the last positions to fall there.

Such an invasion could not depend on sinking the US carriers either. It is entirely possible, even probable, that they would be ordered away from Oahu if the Japanese were camped for an invasion rather than committed to what would be a suicide mission to attack the Japanese fleet.

If the Japanese just committed to staying and hoping the carriers showed up, that too could be a disappointing effort for the same reason. The USN might order them to go elsewhere, rendezvous with a tanker or the like and head for the West Coast or elsewhere to avoid destruction.

Thus, as usual, the most likely outcome is the Japanese fail to take Oahu and cannot support the remaining forces ashore that are pinned in place and eventually destroyed. The Philippines is reinforced and becomes untakeable, or Malaya and Singapore remain untaken, or both. This puts Japan in a bind on their Southern strategy as they now have the enemy on their proverbial doorstep and can't remove them. They end up losing in Hawaii and their whole war plan collapses in ruin. They lose the war by late 1944 and it is likely Germany that gets nuked instead.

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Re: A proper attack on Pearl Harbor

Post by Peter89 » 05 Jun 2020 15:59

T. A. Gardner wrote:
05 Jun 2020 15:40
This has been beaten to death here, probably only second to Seelöwe. Here's an example of an old thread on invading Oahu:

viewtopic.php?f=11&t=159159&hilit=oahu

For Japan to even have a slight chance of success invading Hawaii, they have to give up invading the Philippines or Malaya, possibly even both. They would need the shipping and manpower to land in Hawaii and they have no other alternate source for it. They also still absolutely need the DEI for resources so that's out. It's also vastly harder for them to keep it a surprise move due to the no massive size of the fleet needed and the fact it takes about twice as long to cross the Pacific.

Even then, the chances of success aren't great. The US Army alone has about 40,000 men in Hawaii total. The coast defenses of Oahu are brutally massive. They aren't like the British ones at Singapore either. They can act in all-around defense in large part and cover all of the accessible beaches with massive amounts of firepower. They would also be difficult or impossible to take out for the Japanese just as they were in the Philippines. You might note, they were the last positions to fall there.

Such an invasion could not depend on sinking the US carriers either. It is entirely possible, even probable, that they would be ordered away from Oahu if the Japanese were camped for an invasion rather than committed to what would be a suicide mission to attack the Japanese fleet.

If the Japanese just committed to staying and hoping the carriers showed up, that too could be a disappointing effort for the same reason. The USN might order them to go elsewhere, rendezvous with a tanker or the like and head for the West Coast or elsewhere to avoid destruction.

Thus, as usual, the most likely outcome is the Japanese fail to take Oahu and cannot support the remaining forces ashore that are pinned in place and eventually destroyed. The Philippines is reinforced and becomes untakeable, or Malaya and Singapore remain untaken, or both. This puts Japan in a bind on their Southern strategy as they now have the enemy on their proverbial doorstep and can't remove them. They end up losing in Hawaii and their whole war plan collapses in ruin. They lose the war by late 1944 and it is likely Germany that gets nuked instead.
Thank you for your kind and informative input, Gardner.

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Re: A proper attack on Pearl Harbor

Post by glenn239 » 06 Jun 2020 16:22

T. A. Gardner wrote:
05 Jun 2020 15:40
Thus, as usual, the most likely outcome is the Japanese fail to take Oahu and cannot support the remaining forces ashore that are pinned in place and eventually destroyed. The Philippines is reinforced and becomes untakeable, or Malaya and Singapore remain untaken, or both. This puts Japan in a bind on their Southern strategy as they now have the enemy on their proverbial doorstep and can't remove them. They end up losing in Hawaii and their whole war plan collapses in ruin. They lose the war by late 1944 and it is likely Germany that gets nuked instead.
So what this is saying is that if the Japanese fail to take Hawaii, their war effort collapses in ruin sometime during or after late 1944. If the Japanese do not attempt to take Hawaii, their war effort collapses in 1945. What are you proposing is the strategic difference between the two outcomes, other than that the earlier collapse date avoids the horrific damage to Japan itself that occurred in 1945?

In terms of the Americans actually holding Luzon after a failed invasion of Hawaii, can you outline how that would be feasible?

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Re: A proper attack on Pearl Harbor

Post by glenn239 » 06 Jun 2020 16:39

Peter89 wrote:
05 Jun 2020 13:02

What if the Japanese decision makers decide to launch an all-out attack on Pearl Harbor and succeed in destroying the better part of the US Pacific fleet?
[/b]

So they... take the Hawaii Islands and thus deny the Americans to repair their damaged ships and push the American base of operations 3000 miles eastwards.

That's two separate and distinct things. First, to use the Japanese fleet to destroy the US fleet. Second, to use the Japanese fleet to take Hawaii and push the US base back to California. Yamamoto discovered at Midway that dividing his fleet between two tasks could risk accomplishing neither. The two objectives need to be separated in time and space, with the objective of destroying the US fleet coming first, the objective of taking Hawaii coming second. The trick is that if the second is left off too long, the US reinforces Hawaii and makes the task impossible even if the IJN has scored a major success.

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Re: A proper attack on Pearl Harbor

Post by T. A. Gardner » 06 Jun 2020 18:33

glenn239 wrote:
06 Jun 2020 16:22
So what this is saying is that if the Japanese fail to take Hawaii, their war effort collapses in ruin sometime during or after late 1944. If the Japanese do not attempt to take Hawaii, their war effort collapses in 1945. What are you proposing is the strategic difference between the two outcomes, other than that the earlier collapse date avoids the horrific damage to Japan itself that occurred in 1945?

In terms of the Americans actually holding Luzon after a failed invasion of Hawaii, can you outline how that would be feasible?
What I'm suggesting is that if Japan tries to take Hawaii they probably will fail, but even if they succeed, it shortens the Pacific War by as much as a year or more. It also likely avoids some of the massive damage the Japanese homeland took.

As for Luzon and the PI. If the Japanese fail to invade immediately the Philippine Army of ten divisions ends up being trained and equipped far better than it was. Six months is more than sufficient for that to happen. At that point the Philippine Army would be at a trained strength of about 3 to 5 divisions. All of that was already happening in the PI. The timeline for the Philippine Army to be fully up and trained was August 1942.
The Philippine Division (US Army) would be a full strength triangular or square division with roughly 50% greater strength as it would be fully reinforced. It's fully possible the US sends a second infantry division to the PI as well.
The USAAC/ USAAF in the PI would continue to grow in numbers and with the war on the US would build more airfields and other infrastructure to back that up.
Since Japan in this case won't hold territory that will allow for easy and frequent maritime patrol of approach routes for convoys-- These could go to Mindanao in the South, unload then move to Luzon in smaller craft if necessary, the Japanese have no real means to effect a sea blockade of the PI. They can't stay at sea for the prolonged periods necessary.

Japan failing to take the PI really has little means to stop the US from continuing to move more troops and equipment / supplies there. Holding the DEI alone won't cut it, and the Japanese likely won't invade New Guinea at all. Again, because they put the necessary manpower and shipping into Hawaii. They would have to focus on Malaya first then the PI or the reverse. I think after the DEI they'd try Britain and Malaya before the US in the PI as the PI only represents a potential threat to their sea traffic while bringing little in strategic resources to the table. Malaya represents more rubber and other strategic resources that can be linked by rail to China avoiding sea movement near the PI.

The longer the PI goes uninvaded, the greater the strength the US would have on the ground and in the air there.

Hawaii simply represents a conquest. If Japan succeeds at all that comes at a very high cost and does little to further their strategic goals. The US could and would work around that problem until they could retake the islands if they actually fell, which really isn't that likely. Japan just isn't very good at amphibious warfare and in particular when there's opposition to a landing.

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Re: A proper attack on Pearl Harbor

Post by T. A. Gardner » 06 Jun 2020 18:49

glenn239 wrote:
06 Jun 2020 16:39

That's two separate and distinct things. First, to use the Japanese fleet to destroy the US fleet. Second, to use the Japanese fleet to take Hawaii and push the US base back to California. Yamamoto discovered at Midway that dividing his fleet between two tasks could risk accomplishing neither. The two objectives need to be separated in time and space, with the objective of destroying the US fleet coming first, the objective of taking Hawaii coming second. The trick is that if the second is left off too long, the US reinforces Hawaii and makes the task impossible even if the IJN has scored a major success.
The trick is, how do you accomplish the first at all, and then second what it would take to actually conquer Hawaii.

On the first, after the second attack, most of the US fleet that can get underway likely will and could leave harbor. The almost all of the cruisers in Pearl Harbor are immune to torpedo attack being tied to piers in the Navy Yard. Once most of the fleet escapes the harbor, its going to be nearly impossible to use air power alone to finish them. The Japanese simply don't have the munitions on their carriers for it. They have enough for about 2 more strikes then a dwindling supply that would leave their carriers unarmed for all intents. This is particularly true with torpedoes.

The surface fleet would need to conserve ammunition for a hoped for surface action which means they are short on bombardment munitions for the landing. Or, they go the other way and try to avoid a surface fight.

As I stated, the Japanese are not going to take out the coast defenses of Oahu. Those defenses are some of the strongest on the planet and that's what they're trying to land their troops against. The US has sufficient coast defense guns of sizes they can duke it out with Japan's battleships. Coming in to anchor off Hawaii to land troops means almost certainly losing sufficient numbers of your transport ships that that alone causes the invasion to fail.
Most of the coast of Oahu is unsuited for any sort of amphibious landing as it is cliff, has offshore reef or shallows, is exposed to large waves, etc. The US knew that and covered the most likely approaches with the heaviest guns.

The US has two full infantry divisions on Oahu. For Japan to even have a slight chance to succeed they'd have to bring 5+ infantry divisions of their own with sufficient logistical support for a potentially months long campaign. Because of Hawaii's distance from Japan that eats up several times the shipping invading the DEI, Malaya, or the PI would with the same number of units involved. The round trip takes much longer to Hawaii.

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Re: A proper attack on Pearl Harbor

Post by OpanaPointer » 06 Jun 2020 18:52

Would or would not an invasion of Hawaii bring the full USN into the Pacific? (If this is not germane to the topic please delete.)
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Re: A proper attack on Pearl Harbor

Post by Carl Schwamberger » 06 Jun 2020 20:45

The core problem here is a chronic misunderstanding how War Plan ORANGE & its part in the Rainbow plans worked. WP ORANGE was a long term strategy designed to use US resource & industrial strength. WPO in its various iterations had three years or more to completion. The USN at it existed in 1907 or 1941, or any time between could not conduct a fast war across the Pacific. Thad been repeatedly proven in fleet exercises, map exercises, staff studies. Every admiral knew it. Roosevelt as a former undersecretary of the Navy understood it and as president for eight years regularly brief on naval plans knew it.

At its core WP ORANGE assumed the strategic defense for 12 to 24 months until a massive construction program gave the fleet the logistics train to fight its way across the Pacific & destroy Japans war and commercial fleets.
Peter89 wrote:
05 Jun 2020 13:02
...

The main idea was that the USN Pacific fleet had to be neutralized by one, critical blow, allowing them to establish an economic sphere, the GEACPS.

...

So they destroy Lexington and the Enterprise (and maybe Saratoga), take the Hawaii Islands and thus deny the Americans to repair their damaged ships and push the American base of operations 3000 miles eastwards.
WP ORANGE as it existed 1907 - 1940 had the starting point on the US west Coast 3000 nautical miles further east than Hawaii. It had been expected. In terms of long term strategy this is not a change. OTL the relocation of the Pacific Fleet to Oahu in March 1941 was a threat, but the forward base there was not instantly turned into a strategic base for a strategic offensive. It was 1943 before the Hawaiian islands had enough infrastructure to support the central Pacfic offensive.
How would it affect the Pacific war?

Could the Japanese maintain a quantitative edge until 1943, and fight roughly on equal terms until 1944?
OTL the US destroyed the Japanese quantitative edge by sitting on the strategic defense in 1942. Defeating multiple Japanese attempts to take defended islands between April and December. The Japanese efforts to sustain the offensive destroyed their skilled personnel faster than they could be replaced. Conversely the US was training men far faster than losses, and regularly increasing the standards of the skills required.

When the last carrier battle of 1942 ended the USN had one damaged fleet carrier remaining. The Japanese had two undamaged carriers. But the US had multiple new groups of Naval and Army aircraft enroute to the SE Pacific battlefield. The Japanese were hard pressed to replace losses to the air groups on Rabaul and nothing to restore their carrier wings. Both sides effectively lacked carriers but the US still had a effective & expanding air wing over Guadacannal & New Guinea.
The USN aircraft carriers started to arrive in numbers in 1943 (7 fleet carriers* and 9 light carriers, compared to 0 new Japanese carriers), and they built 7 fleet carriers in 1944. In the meanwhile, the Japanese could reinforce themselves only with 4 fleet carriers and 2 light carriers, all of them starting their services in 1944.

Could they actually fight effectively in 1944?

Or in other words, could the Japanese grand strategy work (until the A-bomb was deployed) if they execute their Pearl Harbor operation perfectly? ...
Not clear what grand strategy you are referring to here. The starting strategy I am familiar with, from Costellos 'The Pacific War' or Beaselys 'The Rise of Modern Japan' was the US would roll over and seek a cease fire within a few months. By May discussions of peace terms would be starting. The long strategy elected by Tojos government as 1942 spun out was a improvised one made when the initial strategy failed. A long neither the plan nor intent when the decision for war developed.

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Re: A proper attack on Pearl Harbor

Post by T. A. Gardner » 06 Jun 2020 21:39

As an example of what I mean, the Pensacola convoy likely would have continued to the PI in this scenario.

That's 4 additional battalions of artillery into the PI, 52 A-24 (USAAF SBD dive bombers), 18 P-40E fighters, 87 pilots, and a mass of ammunition.

All of that likely would end up in the PI here within a week or two of the war starting as there is no general Japanese attack on the PI underway and the area south and east of the PI would not be threatened. It is also likely that the cruisers and destroyers escorting the convoy would be told to join the ABDA fleet rather than return to Hawaii because of the Japanese actions at the later.

The US might also send substantial units from the Atlantic Fleet to the Pacific to help relieve Hawaii in this scenario. While that might take several weeks to accomplish, it is doable within the timeframe of an Hawaiian invasion. If Hawaii doesn't fall rapidly, and that's likely to be the case, the longer the battle goes on, the greater the Japanese chances of not just losing but losing all the committed troops becomes. On the IJN side, their ships cannot stay off Hawaii for more than a few days at most. They simply lack the fleet train to supply them that far from Japan on a sustained basis.

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Re: A proper attack on Pearl Harbor

Post by OpanaPointer » 06 Jun 2020 21:54

Plan Dog was the relevant plan here.
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Re: A proper attack on Pearl Harbor

Post by Peter89 » 07 Jun 2020 08:26

glenn239 wrote:
06 Jun 2020 16:39
Peter89 wrote:
05 Jun 2020 13:02

What if the Japanese decision makers decide to launch an all-out attack on Pearl Harbor and succeed in destroying the better part of the US Pacific fleet?
[/b]

So they... take the Hawaii Islands and thus deny the Americans to repair their damaged ships and push the American base of operations 3000 miles eastwards.

That's two separate and distinct things. First, to use the Japanese fleet to destroy the US fleet. Second, to use the Japanese fleet to take Hawaii and push the US base back to California. Yamamoto discovered at Midway that dividing his fleet between two tasks could risk accomplishing neither. The two objectives need to be separated in time and space, with the objective of destroying the US fleet coming first, the objective of taking Hawaii coming second. The trick is that if the second is left off too long, the US reinforces Hawaii and makes the task impossible even if the IJN has scored a major success.
The Midway operation failed in that sense because the US was prepared, launched a preemptive strike, their radar was online, their carriers were on the hunt, and the carrier air strike was far weaker than the one at PH. The idea was that the Japanese should immobilize/destroy the enemy fleet at anchor, maintain air supremacy until the troopships arrive.

As far as I know, the Japanese air attack on PH originally planned a 3rd wave, which they had the resources for.

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Re: A proper attack on Pearl Harbor

Post by Peter89 » 07 Jun 2020 09:13

T. A. Gardner wrote:
06 Jun 2020 18:33
glenn239 wrote:
06 Jun 2020 16:22
So what this is saying is that if the Japanese fail to take Hawaii, their war effort collapses in ruin sometime during or after late 1944. If the Japanese do not attempt to take Hawaii, their war effort collapses in 1945. What are you proposing is the strategic difference between the two outcomes, other than that the earlier collapse date avoids the horrific damage to Japan itself that occurred in 1945?

In terms of the Americans actually holding Luzon after a failed invasion of Hawaii, can you outline how that would be feasible?
What I'm suggesting is that if Japan tries to take Hawaii they probably will fail, but even if they succeed, it shortens the Pacific War by as much as a year or more. It also likely avoids some of the massive damage the Japanese homeland took.

As for Luzon and the PI. If the Japanese fail to invade immediately the Philippine Army of ten divisions ends up being trained and equipped far better than it was. Six months is more than sufficient for that to happen. At that point the Philippine Army would be at a trained strength of about 3 to 5 divisions. All of that was already happening in the PI. The timeline for the Philippine Army to be fully up and trained was August 1942.
The Philippine Division (US Army) would be a full strength triangular or square division with roughly 50% greater strength as it would be fully reinforced. It's fully possible the US sends a second infantry division to the PI as well.
The USAAC/ USAAF in the PI would continue to grow in numbers and with the war on the US would build more airfields and other infrastructure to back that up.
Since Japan in this case won't hold territory that will allow for easy and frequent maritime patrol of approach routes for convoys-- These could go to Mindanao in the South, unload then move to Luzon in smaller craft if necessary, the Japanese have no real means to effect a sea blockade of the PI. They can't stay at sea for the prolonged periods necessary.
I am not sure how familiar you are with the geography of the Philippines and its defenses in 1941, but fyi its most important cities and trade hubs are all next to the sea, the islands deny the possibility to redeploy forces between besieged garrisons, and the vast shorelines were an ideal ground to amphibitious landings. As for the US reinforcements, I seriously doubt that after the air attacks on Clarck field could be sufficiently reinforced. If the Japanese occupy the Mindanao part of the country and maintain naval and air supremacy, I seriously doubt that the US would not withdrew (just as they did OTL).

Luzon was primarily attacked from Formosa and not from the carriers. What you suggest is basically that is the PI (at least Luzon) would miraculously held out and getting reinforced while the next US base is 1000km away and the Japanese control the air and the seas. And you believe that could be achieved by a few more months of training and a few more additional equipment.

Also, you keep insisting if the Japanese crack units would attack the HI, they could not carry out the attack on the PI. But you completely forget that some other units might, and they don't need to perform miracles, just cutting off the Luzon forces with total naval and air supremacy (basically keep them at bay until the redeployment of more units is possible).

Even if we follow your logic, and the PI could not be invaded in time with any forces, it means two things: the naval forces (including the Ryujo) allocated for the PI invasion would free up, and the land-based Japanese aircraft would still destroy half of the American Far East Air Force in one stroke. In case of a successful invason of the HI, the US forces in the PI would most likely withdraw or if they attempt to hold out, they would be destroyed (although the cost might have been higher). But the point is that they would pose no real threat to the Japanese conquest of the SW Pacific.

Peter89
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Re: A proper attack on Pearl Harbor

Post by Peter89 » 07 Jun 2020 09:25

T. A. Gardner wrote:
06 Jun 2020 18:49
glenn239 wrote:
06 Jun 2020 16:39

That's two separate and distinct things. First, to use the Japanese fleet to destroy the US fleet. Second, to use the Japanese fleet to take Hawaii and push the US base back to California. Yamamoto discovered at Midway that dividing his fleet between two tasks could risk accomplishing neither. The two objectives need to be separated in time and space, with the objective of destroying the US fleet coming first, the objective of taking Hawaii coming second. The trick is that if the second is left off too long, the US reinforces Hawaii and makes the task impossible even if the IJN has scored a major success.
The trick is, how do you accomplish the first at all, and then second what it would take to actually conquer Hawaii.

On the first, after the second attack, most of the US fleet that can get underway likely will and could leave harbor. The almost all of the cruisers in Pearl Harbor are immune to torpedo attack being tied to piers in the Navy Yard. Once most of the fleet escapes the harbor, its going to be nearly impossible to use air power alone to finish them. The Japanese simply don't have the munitions on their carriers for it. They have enough for about 2 more strikes then a dwindling supply that would leave their carriers unarmed for all intents. This is particularly true with torpedoes.

The surface fleet would need to conserve ammunition for a hoped for surface action which means they are short on bombardment munitions for the landing. Or, they go the other way and try to avoid a surface fight.

As I stated, the Japanese are not going to take out the coast defenses of Oahu. Those defenses are some of the strongest on the planet and that's what they're trying to land their troops against. The US has sufficient coast defense guns of sizes they can duke it out with Japan's battleships. Coming in to anchor off Hawaii to land troops means almost certainly losing sufficient numbers of your transport ships that that alone causes the invasion to fail.
Most of the coast of Oahu is unsuited for any sort of amphibious landing as it is cliff, has offshore reef or shallows, is exposed to large waves, etc. The US knew that and covered the most likely approaches with the heaviest guns.

The US has two full infantry divisions on Oahu. For Japan to even have a slight chance to succeed they'd have to bring 5+ infantry divisions of their own with sufficient logistical support for a potentially months long campaign. Because of Hawaii's distance from Japan that eats up several times the shipping invading the DEI, Malaya, or the PI would with the same number of units involved. The round trip takes much longer to Hawaii.
Yes, because we've never known any cases where a well-fortified, unsuspecting fortress fell in WW2.

I guess you simply don't want to refer to my actual questions on this thread.

It is like: "the Germans can't take Eben Emael in time, so the whole Sichelschnitt plan is nuts". I have read well enough about the defenses of the HI here on this forum and in many other books, I never claimed that it was an easy nut to crack. I built up my case on the assumption that the HI were taken, which was not out of the realm of possibilities, as many high ranking officiers noted it, argued for it, etc. It was possible, and this is the What if section, meaning, we presume that the HI were taken.

If you want to continue to answer unasked questions and pour irrelevant data about the Pacific war, go ahead, it's nice to have some activity going on.

I hope you don't get offended. Peace.

Peter89
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Location: Hungary

Re: A proper attack on Pearl Harbor

Post by Peter89 » 07 Jun 2020 09:41

Carl Schwamberger wrote:
06 Jun 2020 20:45
The core problem here is a chronic misunderstanding how War Plan ORANGE & its part in the Rainbow plans worked. WP ORANGE was a long term strategy designed to use US resource & industrial strength. WPO in its various iterations had three years or more to completion. The USN at it existed in 1907 or 1941, or any time between could not conduct a fast war across the Pacific. Thad been repeatedly proven in fleet exercises, map exercises, staff studies. Every admiral knew it. Roosevelt as a former undersecretary of the Navy understood it and as president for eight years regularly brief on naval plans knew it.

At its core WP ORANGE assumed the strategic defense for 12 to 24 months until a massive construction program gave the fleet the logistics train to fight its way across the Pacific & destroy Japans war and commercial fleets.
Indeed. So you think that the Japanese take the HI, they run wild a bit longer, but in late 1943 - early 1944 the US would build up enough resources to defeat Japan regardless of their actions?


OTL the US destroyed the Japanese quantitative edge by sitting on the strategic defense in 1942. Defeating multiple Japanese attempts to take defended islands between April and December. The Japanese efforts to sustain the offensive destroyed their skilled personnel faster than they could be replaced. Conversely the US was training men far faster than losses, and regularly increasing the standards of the skills required.
AFAIK the Japanese naval air forces suffered substantial losses in naval actions as well. Actions that were more or less unnecessary had they been invaded the HI.
When the last carrier battle of 1942 ended the USN had one damaged fleet carrier remaining. The Japanese had two undamaged carriers. But the US had multiple new groups of Naval and Army aircraft enroute to the SE Pacific battlefield. The Japanese were hard pressed to replace losses to the air groups on Rabaul and nothing to restore their carrier wings. Both sides effectively lacked carriers but the US still had a effective & expanding air wing over Guadacannal & New Guinea.
Not clear what grand strategy you are referring to here. The starting strategy I am familiar with, from Costellos 'The Pacific War' or Beaselys 'The Rise of Modern Japan' was the US would roll over and seek a cease fire within a few months. By May discussions of peace terms would be starting. The long strategy elected by Tojos government as 1942 spun out was a improvised one made when the initial strategy failed. A long neither the plan nor intent when the decision for war developed.


As for the grand strategy:
Given the expectation of a long war with the United
States, how did Japan expect to survive? Did Japanese
leaders have a theory of victory, or at least of defeatavoidance?
Japan was not strong enough to threaten
the American homeland, but was not the war going to
be fought in East Asia and the Western Pacific, which
the Japanese controlled or would soon control (after
Tokyo’s conquest of Southeast Asia)? Might Tokyo be
able to fight the United States to a bloody stalemate
on the Japanese side of the Pacific and extract from
that stalemate some kind of political settlement with
Washington that would preserve Japan’s core imperial
interests on the Asian mainland?

These questions point to a third Japanese
assumption, or at least hope: namely, that by swiftly
seizing and fortifying the Central and Southwestern
Pacific, the Japanese could force the Americans
into a murderous, island-by-island slog that would
eventually exhaust their political will to fight on to
total victory. Japan would raise the blood and treasure
costs of the war beyond Washington’s willingness to
pay. “The Japanese theory of victory,” contends Colin
Gray, “amounted to the hope—one hesitates to say
calculation—that the United States would judge the cost
of defeating Japan to be too heavy, too disproportionate
to the worth of the interests at stake.”

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