A Japanese invasion of Hawaii

[Neilster]

I thought this blog post from historian Nigel Davies might be of interest here.

https://rethinkinghistory.blogspot.com/ ... 5Rhhm0lXOk

[Platoonist]

Having read his blog post, I guess find his premise kinda divorced from certain realities. He argues that Japan should have declared war just on the United States alone in 1941, and thrown all the IJA divisions slated for the attack on the Southern Resource Area into a full-bloodied assault on Oahu (and I assume the Philippines). It's probably important to remember that Pearl Harbor for all the lavish attention it gets in books and media was ultimately just a flanking raid in support of the drive on the main prize. Which was to get at the oil and other natural resources in southeast Asia that Japan needed so badly for further expansion. If the Japanese put almost everything into invading Hawaii, I can guarantee that Churchill and Roosevelt will be using that time to fortify Malaya, Sumatra, Borneo and Java to the teeth with Dutch and Australian cooperation. Then, they can sit back for a few months or weeks while the Japanese Imperial Navy ponders where they'll replenish their depleted fuel stocks. Hawaii was a great base of operations for the USN, but it doesn't have much in the way of oil wells. I certainly can't see the ultra-conservative Imperial Japanese Army with its famed antagonism with the IJN, going along with an operation that nets Japan a swell new naval base, but no natural resources.

He seems to feel that Hawaii in Japanese hands could have been used as some sort of bargaining chip in return for peace, and maybe joint ownership of Singapore, but I think the Allies would have just contemptuously laughed off any such offer. With Japan cut off from fuel, time is on their side.

Furthermore, in an invasion of Oahu the Japanese would have to secure continuous air superiority over the Hawaiian Islands with carrier assets alone. However, even at the apex of its power, the Kido Butai never had the logistic ability to stand off of an enemy's island bastion for weeks on end and beat its ground forces into submission. The Kido Butai could mount devastating hit and run raids, but couldn't project the kind of sustained air support that the US Navy could later in 1944 through the use of a fleet train and vast fleet of escort carriers to ferry in planes and pilots to replace those lost though attrition.

In addition, the Japanese would unquestionably have been landing directly in the face of heavy resistance at Oahu. The few experiences the Japanese had had with direct amphibious assaults in the war like at Wake Island don't bode well. That operation clearly showed that the Japanese had little in the way of a budding amphibious doctrine like the U.S. Marine Corps. Instead, when presented with a situation requiring an amphibious assault, the Japanese much preferred to go ashore well away from the main objective on more thinly defended coastlines like they did in Malaya and Luzon. In Oahu, the Japanese would land in the face of a concentrated enemy with substantial forces in reserve and plentiful mountainous ridges to defend on.

I also think the third raid he enthusiastically endorses to knock out the oil farms and navy facilities at Pearl would have just lost Japan more precious planes and pilots. In any case, the benefits of such an attack on the Oahu installations may not have been so great as many believe. Alan Zimm in his 2011 book concluded that a third wave attack concentrated on the Navy Yard would not have destroyed more than 12% of the facilities even under the most ideal assumptions, while the oil tanks (and oil) would have been relatively easy to replace.

[warspite1]

I agree. ‘What ifs’ can be interesting to explore, but when the ‘what if’ is so divorced from reality it becomes pointless and pure fantasy. Imagine the sheer logistical effort required and the number of ships that would need to be employed - not just to try and take the islands, but to hold them. There are so many other factors too. But only one is needed to be mentioned to evidence the nonsensical nature of this ‘what if’....... oil.

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[Curtis Lemay]

I do kind of like the idea of handling Pearl Harbor separately from the rest of the invasions. The advantage of that is that it would give the Pearl Harbor attack some time flexibility. When all the other operations took place in synch with Pearl Harbor, then, when the Jap carriers arrived off Pearl and there were no US carriers in port, the attack still had to go forward. On the other hand, if every other operation can just wait till Pearl goes off, then Pearl can be aborted a couple of tries till the carriers are in port. There was nothing urgent about the kick-off date of the war. It would have waited a week or two.

As for invading Hawaii, it can be pulled off successfully in every sim I've ever played. It's not necessary to invade Oahu right off. Just take the surrounding (largely undefended) islands, fly in land-based bombers and go from there. The carriers can then be released for the other operations.

[ncc1701e]

Bringing supplies there would have been challenging. Funny that we are currently discussing an early invasion of Noumea in January 1942 in Warplan Pacific sub forum.

[Torplexed]

Seems pretty far-fetched. By 1941 Japan had made too many too enemies to concentrate just on one and hope the others would sit by passively waiting for their turn next. It's also vital to remember that the size of Japan's amphibious lift pool at the time was rather limited. This pool was about sufficient to shift 11 divisions around the Pacific and still keep the army on the Chinese mainland in supply and the Japanese populace fed. This, in turn, severely restricted the potential extent of Japanese operations. Japan had to seize what it could with eleven divisions, and no more.

Committing three divisions (or even more) to an attack on distant Hawaii makes no strategic sense. As noted, the penultimate goal of the war the Japanese had committed themselves to was securing the resources of the Southwest Pacific (oil) as quickly as possible. The luxury of time was distinctly not in Japan's favor. Her petroleum stockpiles were insufficient for protracted hostilities, and her domestic production was meager compared to her military needs (particularly the Navy). Thus, committing amphibious forces to an objective which did not involve the securement of new oil sources would have been just plain dumb, and doubtless would have bittered opposed by the Imperial Army staff. Japan needed every one of those 11 divisions right where they were committed historically.

Another item to bear in mind was the Pearl Harbor raid was planned in greatest secrecy to achieve surprise. As few members of Japan's ruling class and military junta were told of its existence as possible. An amphibious operation of 50,000 men across 4,000 miles of open ocean means a staggering array of navy, army officers and civilian officials are going to have to be brought into the scheme to plan it out. That means more tongues wagging, and profligate coded messages possibly being intercepted by Allied traffic analysis in order to assemble the shipping and logistics. I just can't see an operation of this size and complexity going magically unnoticed.

[Curtis Lemay]

Bringing supplies there would have been challenging.

More challenging for the US than for the Japs. The Zero has enough range to fly there from in-range bases. US fighters have to be delivered by ship - hard to do in the face of the sea interdiction the Japs would enjoy.

[Curtis Lemay]

Japan needed every one of those 11 divisions right where they were committed historically.

No oil in the Philippines. That operation could have been delayed indefinitely - provided the air and naval assets were sufficiently degraded.

[TulliusDetritus]

[...] committing amphibious forces to an objective [PH] which did not involve the securement of new oil sources would have been just plain dumb [...]

Dumb?? The Japanese knew the real, dangerous enemy was the US. Pearl Harbor is captured, now open an atlas and tell what are the US choices. From Panama to Galapagos? Then to Tahiti?? etc Samoa, Fiji etc

Or concentrate in Australia and start from there?

In both scenarios flanks are exposed if the US try to advance. PH was critical. In Japanese hands, the best shield ever if you ask me. Oil is safe

[Torplexed]

No oil in the Philippines. That operation could have been delayed indefinitely - provided the air and naval assets were sufficiently degraded.

The Philippines sat directly astride the Japanese supply lines which would (presumably) soon be carrying the bounty of the Southern Resource Area back to the Empire--assuming Japan ever wanted to have oil to run its fleet at some future point. Leaving an enemy force in such a flanking position was not an option. Indeed, Japan's initial war plans contemplated moving against the Dutch East Indies only after the Philippines were completely in Japanese hands.

For the very same reasons, Malaya also had to be captured. It didn't have much oil either but the British presence on the peninsula, and the enormous naval base in Singapore, were like a knife pointed at the Dutch East Indies. Malaya could not therefore be bypassed safely; it had to be taken out as well. Taken in this light, it is scarcely surprising that the Philippines and Malaya between them accounted for more than half of the total Japanese ground forces deployed in the initial campaign, and more than 90% of the Army's amphibious tonnage alone.

Of the remaining combat theatres, Burma was perhaps the least vital to the whole operational concept. However, it was still important in securing the flank of Malaya from the threat of British counterattacks mounted from the Indian frontier, or via the sea against the Malayan isthmus. Furthermore, the forces committed to Burma, comprising a division and a regimental group, had the advantages of being fairly small. They could also be deployed via Thailand, thus conserving valuable sealift capability. The division assigned to capture Hong Kong was much the same story, except that it was also earmarked for subsequent deployment against the Indies themselves and could not thus be assigned elsewhere. Finally, the regimental team charged with overrunning all of the South Pacific was important to ensuring that Wake, Guam, and the other minor American bases caused no trouble on the frontier. The bottom line is that the Japanese might have abandoned the campaign against Burma without upsetting the logic of the larger plan. But the division and a third thus freed up was scarcely capable of securing Hawaii in the face of 40,000+ American Army troops.

[Torplexed]

Dumb?? The Japanese knew the real, dangerous enemy was the US. Pearl Harbor is captured, now open an atlas and tell what are the US choices. From Panama to Galapagos? Then to Tahiti?? etc Samoa, Fiji etc

Or concentrate in Australia and start from there?

Given the scenario the historian originally posted above I'd move a fair portion of the US fleet to Singapore and Java and work from there. Something Churchill had asked for before the war even broke out. It's a long trip but it can be reached via the Cape of Good Hope. Remember, this amateur historian Nigel Davies is proposing that Japan does not declare war on Britain or the Netherlands in 1941. However, I'm certain Churchill and the Commonwealth would know they were next on the list and wouldn't hesitate to let the US fleet and even army in. I'm also curious as to what the Japanese economy is going to be running on after a few months if they forgo attacking the Dutch East Indies, Pine root oil?

[TulliusDetritus]

Given the scenario the historian originally posted above I'd move a fair portion of the US fleet to Singapore and Java and work from there.

hmm, what fleet...? You mean the Hornet, Yorktown and Wasp + their screens (CAs + DDs)? And let the US West Coast totally undefended? Not sure the political head aka big boss FDR would have allowed this. I already mentioned it on these forums, I had read Nimitz' papers and was surprised to read (sitrep early january 1943) that basically Japanese might try to grab errr the Hawaiian islands. This when the successful Guadalcanal campaign was basically won.

And yet... the big boss prefers prudence... you never know

[Curtis Lemay]

No oil in the Philippines. That operation could have been delayed indefinitely - provided the air and naval assets were sufficiently degraded.

The Philippines sat directly astride the Japanese supply lines which would (presumably) soon be carrying the bounty of the Southern Resource Area back to the Empire--assuming Japan ever wanted to have oil to run its fleet at some future point. Leaving an enemy force in such a flanking position was not an option. Indeed, Japan's initial war plans contemplated moving against the Dutch East Indies only after the Philippines were completely in Japanese hands.

Once the air and naval assets were degraded, the Philippines - deep behind Jap lines - would be neutralized for quite a while. I would remind that Nimitz was in favor of bypassing it in 1944 - overruled by Mac's "I will return" speech.

[warspite1]

We all know that this operation would never have had the IJA’s co-operation, but let’s suspend disbelief and say that the army were fully on-board.

Let’s also say that the invasion would have succeeded ultimately. Given Japanese performance in the war generally I am surprised that this is treated as an almost given, but let’s go with that too. We’ll assume this massive, slow moving invasion force + escorts was never missed by intelligence and never located while making its way across the Pacific. We’ll also assume if suffered no losses to land based air or submarine (or indeed surface forces had it been detected).

So in summary, this dream Japanese scenario was undertaken and was a success. So why, even when looked at through that lens is this article not in any way interesting or thought-provoking?

Well first and foremost we have the Japanese elephant in the room…. Oil.

Mention the Mediterranean and the Italians, and one can guarantee OIL is quickly brought up. Surprisingly this doesn’t happen to the same degree when Japan’s options are discussed. The article is no different and proposes that the quest for oil is delayed due to the expanded Hawaiian operation.

So what was Japan’s real life oil situation on 7 December 1941? What was Japan’s oil situation once oil finally starting being obtain from the NEI in 1942? Silence.

What does this massive, expanded Hawaiian operation cost the Japanese in terms of increased oil usage? We can get some idea from what Midway cost the Japanese. This operation would not have been quite as big as Midway, but it’s not going to be that far off. But again that is glossed over.

When is the invasion of the NEI now going to happen? What about Malaya/Philippines? Assuming the Japanese are equally as successful (another far from given considering the Dutch/British/US have had more warning to organise and prepare) when does oil start to be added to the Japanese war effort in this scenario?

The article airily talks about all the things the IJN can do along the US west coast and in Panama without any comments on the additional oil being consumed. But that is not surprising given it also airily dismisses the loss of two carriers and half the air fleet before the war has really started. Perhaps the writer is not aware of the dearth of replacements being trained by the Japanese?

What stocks of oil are captured (let’s again suspend disbelief and assume the US forces on the island don’t have the presence of mind to sabotage their oil stocks (and harbour facilities))? This is a pretty key point to include in any Hawaii invasion scenario.

There is talk in the article of the Japanese salvaging the less damaged US warships. Well again, let’s assume the US forces on the island are so dumb they don’t scuttle their ships or repair facilities (or for some reason are unable to – the British didn’t do a great job in Singapore…). But again, let’s assume that happens. The Japanese barely had enough oil for their own battleships (especially after Midway) so, even if they did manage to put some US warships back into service, how long would that take and where does all this oil come from? This is why the article needs to comment on what realistically the Japanese could have captured.

Other

What aircraft are required to defend Hawaii and where do these (and their fuel) come from? Does this affect the invasions in west still to come? Will the air fleet that sunk Force Z be required in Hawaii?

Assuming US submarines had to sail from the west coast, what sort of counter-attack (against US transports and supply vessels) did they have the range to mount? Again, no comment on this.

Assuming no US ship in Pearl was able to get out, exactly what did the USN lose over and above what they lost in reality? How many ships (not including long term battleship repairs) would have been wiped from the USN order of battle?

How quickly, and with what, could Churchill have reinforced Malaya and the NEI? This scenario assumes (it assumes a lot doesn’t it?) that the oil of the NEI would have been ultimately taken, but given what actually happened – the Japanese on the verge of running out of supplies in Malaya – there is no guarantee that even a slightly better prepared British/Dutch defence, would have still seen the same easy victories for the Japanese. And then there is the Philippines to consider.

The Japanese attack in real life was swift and bold. American, Dutch and British possessions were taken within the first months of 1942 with the Allies simply reacting from one disaster to another - and of course the most important of these was the oil of the NEI. But under this scenario, with all Japanese focus on Hawaii initially, the Allies would have had a chance to react to the reality of the Japanese position. Stop them taking the NEI quickly and the Japanese war machine is going to grind to a halt pretty quickly. Could the Allies have formed their defensive strategy on that basis alone? And if so, how much could they have delayed (or even stopped) the Japanese? Well it wouldn’t have been pretty for Japan if they did.

This article could have been interesting if the writer was able to add some of the key points that really mattered. Sadly the boring, un-sexy things like logistics (you know, the stuff crucial to the winning of battles and wars) was not considered relevant….. Shame.

[Curtis Lemay]

Well, it seems you're just going to focus on the article, rather than the general idea of an invasion of Hawaii - a more defendable topic.

[warspite1]

It doesn't matter if its the article or the idea of the invasion. Either way, a supporter of the idea that the invasion would have been a good move for Japan, needs to answer the questions on oil. Everything else is pointless without this.

In real life, Japan had a problem after the oil embargo. She needed oil. The NEI was where she could obtain that oil. Japan sought to get that oil as soon as she practically could.

If, through some other strategy, she was to delay that move, then she needed to be:

a) pretty certain the delay would be manageable (in terms of timescale)
b) that the conquest of the NEI would not be made more difficult/impossible by that delay (by alerting the enemy and giving them a chance to organise and prepare)
c) that whatever caused the delay (in this case a Hawaiian invasion following, and as part of, the attack on PH) would be acheivable with a very high degree of success (given the losses that would be incurred and the additional oil expended).

It's that simple because even taking Hawaii, and thereafter the PI and/or Malaya and/or Singapore and/or Burma and/or blah blah blah, matters not a single jot if they don't take the NEI. Japan's industrialised economy will literally grind to a halt and Japan loses the war without it.