A Japanese invasion of Hawaii

[Platoonist]

At the time the Pearl Harbor raid was conceived the Japanese Navy General Staff believed the operation to be reckless. Fearful of its outcome, the chiefs of staff of the 1st and 11th Air Fleets recommended, in writing, that the raid be dropped. One of those protesting was Rear Admiral Onishi Takijiro, who in 1944 formed the first Special Attack (Kamikaze) squadrons. In other words, these objections came not from the more hidebound elements of the Japanese military, but from men willing to take risks and endorse unorthodox actions. Onishi, knowing that Japan could only win through a negotiated peace, told Yamamoto that Japan should "avoid anything like the Hawaii operation that would put America's back up too badly".

After a round of war-games, the flag officer assigned to execute the attack and most of the Naval General Staff wanted nothing to do with it. When the decision was made irrevocable, officers on the Naval General Staff feared disaster, they implored Admiral Nagumo, the Kido Butai commander, "to exert every effort to preserve his force and get out of the area as soon as possible." The attitudes of the naval aviators embarked for the raid were just as fatalistic. Most of the flying officers were convinced they would never come back alive. The Japanese strike commander estimated his men had a 50-50 chance of surviving. One aviator recalls saying as he departed his carrier on the morning of the attack. "Goodbye Kaga. we'll probably never see you again".

Now, if this was the prevailing attitude among forward thinking naval officers at the time to what was conceived as a bold tip-and-run raid, how would you ever get the support of the ultra-orthodox Army brass to a full-blown invasion? It's easy to overlook the prevailing contemporary mindset in Japan that saw Hawaii (much as the Americans saw Truk) as a Gibraltar-like fortress in the Pacific. Yamamoto himself was prepared to lose at least two carriers in the operation. Since the operation was a resounding and surprising success, there is a tendency with hindsight to think Hawaii was thus a pushover, and the Japanese should have dragged an army along and just dropped it on the beach to mop-up the demoralized Americans. However, that wasn't the mindset at the time.

I think that is often the problem with alternate history scenarios. We often take a "if I ran the zoo" mentality of total control and perfect 20-20 hindsight and apply it to a real life political and cultural situation where there is going to be a great deal of internal opposition and concerns that just can't be easily brushed off and glossed over. Especially when it comes to the oil question. The Japanese war machine can't operate on Hawaiian pineapple juice alone. In just carrying out the PH raid alone the Japanese were already going miles outside the comfort zone of all their decades of pre-war planning and assumptions of a war with the United States. Proposing an multi-division invasion of Hawaii at the time to go along with it probably would have sounded like asking for an invasion of the far side of the moon.

[Curtis Lemay]

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.

If you read my first post, I only want the option to abort the raid if the carriers aren't in port. Everything else would be aborted each time as well. Eventually the raid takes place - when the carriers are in port. Only then does everything else get the green light. Maybe those operations are slightly delayed relative to Pearl, but not by much. Certainly not enough to enable the US or UK to send anything to Singapore or the Dutch East Indies ahead of the Japs. The best part of this (for the Japs) is that the carriers are much more likely to be sunk in the raid. So the oil targets are secured about on the historical schedule - relative to Pearl. Only the Philipines are delayed.

But, also, this is an opportunity to take the neighboring islands around Oahu. Since they are basically undefended, this doesn't require any huge invasion fleet. A few battalions on destroyers will work. Then, air groups are shifted from where the historical eastern boundary had been to those islands around Pearl. Then they can take their time degrading Oahu while holding any US sea assets at bay. Larger occuping forces can be delivered to the islands days later. Perhaps, after much degrading, Oahu can be tried for. But it isn't necessary. While those islands are controlled by the Japs, Oahu is unusable.

[warspite1]

If you read my first post, I only want the option to abort the raid if the carriers aren't in port. Everything else would be aborted each time as well. Eventually the raid takes place - when the carriers are in port. Only then does everything else get the green light. Maybe those operations are slightly delayed relative to Pearl, but not by much. Certainly not enough to enable the US or UK to send anything to Singapore or the Dutch East Indies ahead of the Japs. The best part of this (for the Japs) is that the carriers are much more likely to be sunk in the raid. So the oil targets are secured about on the historical schedule - relative to Pearl. Only the Philipines are delayed.

warspite1

So are you saying the KB could sail to HI, and what, send a recce mission over the islands and if the carriers are away, they would sail back? And then repeat the process until they catch the carriers in port? Each time expending oil, wear and tear on machines, increasing the chance of detection, not to mention the colossal strain on sailors and airmen?

Equally, the troops earmarked for Malaya, PI etc are loaded and unloaded countless times waiting for confirmation that the carriers are at Pearl?

[warspite1]

But, also, this is an opportunity to take the neighboring islands around Oahu. Since they are basically undefended, this doesn't require any huge invasion fleet. A few battalions on destroyers will work. Then, air groups are shifted from where the historical eastern boundary had been to those islands around Pearl. Then they can take their time degrading Oahu while holding any US sea assets at bay. Larger occuping forces can be delivered to the islands days later. Perhaps, after much degrading, Oahu can be tried for. But it isn't necessary. While those islands are controlled by the Japs, Oahu is unusable.

warspite1

Assuming this worked and the troops landed, what number of troops are you suggesting? How many islands have airfields? Where are the aircraft coming from to operate from these airfields? How does fuel and ordnance get landed and transported to said airfields? How are the troops fed and supplied?

Sounds like a receipe for total disaster, the KB aircraft being whittled down to nothing, the pilots totally exhausted and the troops suffering a similar fate to those on Guadalcanal.....

[Curtis Lemay]

So are you saying the KB could sail to HI, and what, send a recce mission over the islands and if the carriers are away, they would sail back? And then repeat the process until they catch the carriers in port? Each time expending oil, wear and tear on machines, increasing the chance of detection, not to mention the colossal strain on sailors and airmen?

Equally, the troops earmarked for Malaya, PI etc are loaded and unloaded countless times waiting for confirmation that the carriers are at Pearl?

No recon mission. They had spies in Pearl that made the report. This would be made a day or two before the Japs got to the launch point. The other operations would hold a few days or so away from their objectives.

Colossal strain? Compared to being a Kamikaze?

[Curtis Lemay]

Assuming this worked and the troops landed, what number of troops are you suggesting? How many islands have airfields? Where are the aircraft coming from to operate from these airfields? How does fuel and ordnance get landed and transported to said airfields? How are the troops fed and supplied?

Sounds like a receipe for total disaster, the KB aircraft being whittled down to nothing, the pilots totally exhausted and the troops suffering a similar fate to those on Guadalcanal.....

Initially, the troops (a few battalions, as I said) and supplies are landed via destroyers (as the Japs used frequently for small invasions). Most of the neighboring islands had ports and airfields. The carriers are long gone and are not being worn down or risked. These would be land based fighters and bombers flown in from the closest Jap held eastern islands. Once Oahu's air assets have been sufficiently degraded, larger occupying forces could be landed and supplied by normal cargo shipping. Right after Pearl, the US was not the same US as at Guadalcanal.

[RangerJoe]

Capturing the Hawaiian Islands was feasible. Oahu would have been harder but on the 7th of December there were no troops on the beaches. The Japanese could have started to land that night or early the next morning. There would not have been enough troops to cover every beach.

Japan had enough oil for months, the fleet would have been fine for awhile. Midway could have been grabbed on the 7th of December as well as some other islands in the Hawaiian Island chain.

[warspite1]

So are you saying the KB could sail to HI, and what, send a recce mission over the islands and if the carriers are away, they would sail back? And then repeat the process until they catch the carriers in port? Each time expending oil, wear and tear on machines, increasing the chance of detection, not to mention the colossal strain on sailors and airmen?

Equally, the troops earmarked for Malaya, PI etc are loaded and unloaded countless times waiting for confirmation that the carriers are at Pearl?

No recon mission. They had spies in Pearl that made the report. This would be made a day or two before the Japs got to the launch point. The other operations would hold a few days or so away from their objectives.

Colossal strain? Compared to being a Kamikaze?

warspite1

Okay so how many carriers need to be at Pearl? 1? 2? 3? for the Japanese to stop tooling around in the North Pacific and make the attack?

Saratoga is off getting damage fixed (I think she left at some point in early November) so she's out of it for sometime and the Japanese won't know when she is to return. But let's assume its 2 carriers required. Enterprise left Pearl on the 28 November - I believe the same date that Nagumo left Japan. Of course the Japanese won't know how long she's going to be gone for. Then Lexington left on the 5 December - again there is no way of knowing how long for.

So this plan is not going well is it? And indeed there was no guarantee 2 carriers would ever be in Pearl at the same time or when that would happen if they were. Of course it was likely they would be back together at some point in (mid?) December - but how long for before one or both left again? In the meantime you've got the KB going back and forth in the inhospitable North Pacific like some kind of horizontal yo-yo. Presumably you envisage a relay of tankers would be required to ensure that the ships can be continually topped up.

The comment about Kamikazes and strain on pilots and troops and how long they can be placed on alert and then stood down, alert, stood down is totally pointless to the discussion, but I notice you've picked up on this and not the wear and tear, oil usage and danger of detection.

Do you know when the invasion forces for Malaya alone were required to set off in order to achieve surprise alongside Pearl? The ships would have to set out before the 1 or 2 day notice period from Pearl. More back and forth, more oil wasted, more change of detection, more wear and tear on ships and men.

I've got to say, this is one bonkers 'plan'.

[warspite1]

Assuming this worked and the troops landed, what number of troops are you suggesting? How many islands have airfields? Where are the aircraft coming from to operate from these airfields? How does fuel and ordnance get landed and transported to said airfields? How are the troops fed and supplied?

Sounds like a receipe for total disaster, the KB aircraft being whittled down to nothing, the pilots totally exhausted and the troops suffering a similar fate to those on Guadalcanal.....

Initially, the troops (a few battalions, as I said) and supplies are landed via destroyers (as the Japs used frequently for small invasions). Most of the neighboring islands had ports and airfields. The carriers are long gone and are not being worn down or risked. These would be land based fighters and bombers flown in from the closest Jap held eastern islands. Once Oahu's air assets have been sufficiently degraded, larger occupying forces could be landed and supplied by normal cargo shipping. Right after Pearl, the US was not the same US as at Guadalcanal.

warspite1

So you envisage that the Hawaiian main island has not been taken and there are still US ships and submarines capable of sailing. There are still some aircraft available for service. But you say an unspecificed number of Japanese destroyers are going to sail to an unspecified number of islands where there are an unspecified number of airfields from which Japanese aircraft can fly to with impunity and then carry out operations against Oahu? As for how they get there in the first place, what fighters have the range to reach Pearl - indeed how many bombers?

So how are these aircraft, that magically appear on these islands, replenished with fuel and ordnance? They are serviced how? They are protected from air attack how? Even assuming the Americans don't attack them, they will suffer severe attrition over the main island from AA, accident etc. and so they are reinforced how? What is the food supply situation on these various islands?

Where do these magical aircraft come from? A look at the history of the Pacific War evidences that Japan simply didn't have enough aircraft to do what was required. Aircraft for these 'island holdings' need to come from somewhere. Which operation loses its aircraft? Malaya? PI? NEI?

[TulliusDetritus]

I have a big problem with the nefarious "no, this or that could not be done".

Most of the average military historians don't know what they are talking about. Don't get me wrong. One thing is the tactical minutiae (here they are experts no doubt) but to pontificate about possibilities or choices you need to master the economic life of x state. And this alone is a huge task. Industry, agriculture, transports, budget, political factions etc etc etc

An Adam Tooze can indeed produce such a work but your average military historian, no, no and no. Just because some guy once said "no, impossible" and people repeat one thousand times this mantra does not mean it's true

Then you need to consider that this "impossible" thing has nothing to do with real possibilities (again, understanding the economic life is a must) but with political choices or decisions. And here, Warspite, relax. The best example is of course Churchill. "Impossible" in fact means and only means = "I don't want to do this or that -because I'm here to defend MY interests- ergo I need some alibi". There are many Churchills out there eh

I will not add anything. Just repeat once again that a real life commander (the top boss in fact, subordinated to King though) did not rule out this possibility (early 1943 rofl). He was living in the moon apparently.

[Aurelian]

So where were the troops and transports going to come from to invade Hawaii? What operation was going to be put off to do it. Then, how are you going to hold it? There were at least 15,000 troops on O'ahu.

Everything, food, munitions, spare parts, medical supplies, everything would have to be imported. One thing to send DDs carrying a minimal number of troops that can use the boats. Quite another to use transports that need a port to unload.

Then you have the American carriers. They would do in Hawaii what they did in early 1942, hit and run raids. Then we have the submarines surrounding the islands. Japanese ASW was not that great. They could sink a great many transports, even with the torpedo problem. You can have the CVs raiding the airfields while the B-17s coming from the mainland bombing everything.

Hawaii would be at the end of a long, fragile, logistical chain. It couldn't be held for long.

[RangerJoe]

The only reason why the USS Enterprise was not at Pearl Harbor on the 7th of December was because it was delayed by a storm.

That said, don't wait for the carriers to be in port. Use the same time table as the actual attacks. Invasion forces for some of the smaller and undefended islands could have been on unescorted ships. Food was grown on the islands, so a lot of food would not have need to be brought along for those detachments. The same for the larger invasion forces although some escorts would have been needed but oilers could also have accompanied these task forces but detached before the actual invasion which if timed correctly would not have been contested for awhile.

[Curtis Lemay]

Okay so how many carriers need to be at Pearl? 1? 2? 3? for the Japanese to stop tooling around in the North Pacific and make the attack?

Saratoga is off getting damage fixed (I think she left at some point in early November) so she's out of it for sometime and the Japanese won't know when she is to return. But let's assume its 2 carriers required. Enterprise left Pearl on the 28 November - I believe the same date that Nagumo left Japan. Of course the Japanese won't know how long she's going to be gone for. Then Lexington left on the 5 December - again there is no way of knowing how long for.

So this plan is not going well is it? And indeed there was no guarantee 2 carriers would ever be in Pearl at the same time or when that would happen if they were. Of course it was likely they would be back together at some point in (mid?) December - but how long for before one or both left again? In the meantime you've got the KB going back and forth in the inhospitable North Pacific like some kind of horizontal yo-yo. Presumably you envisage a relay of tankers would be required to ensure that the ships can be continually topped up.

Ships sailing the sea! Impossible! Yes, they have to be refueled and they have to hold well beyond the launch point if aborted. If they're detected at that distance it tells no one anything - they're just "training". The carriers being absent on a Sunday was an exception.

The comment about Kamikazes and strain on pilots and troops and how long they can be placed on alert and then stood down, alert, stood down is totally pointless to the discussion, but I notice you've picked up on this and not the wear and tear, oil usage and danger of detection.

Let's be clear: The Japanese had no issue with ordering their men to strap on an obsolete aircraft loaded with bombs and fuel and to suicidally fly that plane into an enemy ship. if they could do that, a few sea voyages seems really minor.

Do you know when the invasion forces for Malaya alone were required to set off in order to achieve surprise alongside Pearl? The ships would have to set out before the 1 or 2 day notice period from Pearl. More back and forth, more oil wasted, more change of detection, more wear and tear on ships and men.

Reminder: The invasion forces for Malaya WERE detected, long before they arrived. No action was taken by the Allies. The Allies were close to oblivious about Japan's intentions and their C&C was on a very peace-time footing. No field commander had the green light for anything. Action required a long political process.

I've got to say, this is one bonkers 'plan'.

Launching Pearl without ensuring the carriers were in port was bonkers.

[Curtis Lemay]

So you envisage that the Hawaiian main island has not been taken and there are still US ships and submarines capable of sailing. There are still some aircraft available for service. But you say an unspecificed number of Japanese destroyers are going to sail to an unspecified number of islands where there are an unspecified number of airfields from which Japanese aircraft can fly to with impunity and then carry out operations against Oahu? As for how they get there in the first place, what fighters have the range to reach Pearl - indeed how many bombers?

So how are these aircraft, that magically appear on these islands, replenished with fuel and ordnance? They are serviced how? They are protected from air attack how? Even assuming the Americans don't attack them, they will suffer severe attrition over the main island from AA, accident etc. and so they are reinforced how? What is the food supply situation on these various islands?

Where do these magical aircraft come from? A look at the history of the Pacific War evidences that Japan simply didn't have enough aircraft to do what was required. Aircraft for these 'island holdings' need to come from somewhere. Which operation loses its aircraft? Malaya? PI? NEI?

All those questions could be answered if you'd play a few wargames on the Pacific War - as I've done. It's doable. The sims say so. I've described how they do it. They take the undefended neighbor islands, then fly zeros (very long range) and Betty bombers into the airfields there (Bettys were torpedo capable). They then have their way with everything else on Oahu and every ship trying to get to/from Oahu. Initially, supplies are delivered by destroyer (as done in several other Jap invasions.) But, as the situation deteriorates for the US, normal supply lines can be established.

[RangerJoe]

So where were the troops and transports going to come from to invade Hawaii? What operation was going to be put off to do it. Then, how are you going to hold it? There were at least 15,000 troops on O'ahu.

Everything, food, munitions, spare parts, medical supplies, everything would have to be imported. One thing to send DDs carrying a minimal number of troops that can use the boats. Quite another to use transports that need a port to unload.

Then you have the American carriers. They would do in Hawaii what they did in early 1942, hit and run raids. Then we have the submarines surrounding the islands. Japanese ASW was not that great. They could sink a great many transports, even with the torpedo problem. You can have the CVs raiding the airfields while the B-17s coming from the mainland bombing everything.

Hawaii would be at the end of a long, fragile, logistical chain. It could be held for long.

The Philippines could have had a division redirected, while the 38th could have been diverted from the Hong Kong operation. Troops could have been loaded on civilian transports and appear at islands other than Oahu on the morning of the 7th of December and just tie up to a dock. Not much food would have needed to be brought since there was food grown on the islands.

B17s did not have the range to bomb the Hawaiian Islands from the mainland. The bombers being flown there had no weapons either since they were removed to lessen the weight to increase their range.

[RangerJoe]

Okay so how many carriers need to be at Pearl? 1? 2? 3? for the Japanese to stop tooling around in the North Pacific and make the attack?

Saratoga is off getting damage fixed (I think she left at some point in early November) so she's out of it for sometime and the Japanese won't know when she is to return. But let's assume its 2 carriers required. Enterprise left Pearl on the 28 November - I believe the same date that Nagumo left Japan. Of course the Japanese won't know how long she's going to be gone for. Then Lexington left on the 5 December - again there is no way of knowing how long for.

So this plan is not going well is it? And indeed there was no guarantee 2 carriers would ever be in Pearl at the same time or when that would happen if they were. Of course it was likely they would be back together at some point in (mid?) December - but how long for before one or both left again? In the meantime you've got the KB going back and forth in the inhospitable North Pacific like some kind of horizontal yo-yo. Presumably you envisage a relay of tankers would be required to ensure that the ships can be continually topped up.

Ships sailing the sea! Impossible! Yes, they have to be refueled and they have to hold well beyond the launch point if aborted. If they're detected at that distance it tells no one anything - they're just "training". The carriers being absent on a Sunday was an exception.

The comment about Kamikazes and strain on pilots and troops and how long they can be placed on alert and then stood down, alert, stood down is totally pointless to the discussion, but I notice you've picked up on this and not the wear and tear, oil usage and danger of detection.

Let's be clear: The Japanese had no issue with ordering their men to strap on an obsolete aircraft loaded with bombs and fuel and to suicidally fly that plane into an enemy ship. if they could do that, a few sea voyages seems really minor.

Do you know when the invasion forces for Malaya alone were required to set off in order to achieve surprise alongside Pearl? The ships would have to set out before the 1 or 2 day notice period from Pearl. More back and forth, more oil wasted, more change of detection, more wear and tear on ships and men.

Reminder: The invasion forces for Malaya WERE detected, long before they arrived. No action was taken by the Allies. The Allies were close to oblivious about Japan's intentions and their C&C was on a very peace-time footing. No field commander had the green light for anything. Action required a long political process.

I've got to say, this is one bonkers 'plan'.

Launching Pearl without ensuring the carriers were in port was bonkers.

No action was taken by the Allies? I believe that a Hudson bomber was shot down an hour and a half before the Pearl Harbor raid. The British thought that they were the target, they tried to send troops into Thailand to their primary defensive positions but they were not allowed there to go by Thailand. The commander did not have the troops go to their secondary positions for 24 hours.

The British did not want to open hostilities, neither did MacArthur in the Philippines but the Asiatic surface fleet with support vessels was redeploying to operate with the other ABDA forces in that area. Admiral Phillips was actually in Manila at that time.

[Curtis Lemay]

No action was taken by the Allies? I believe that a Hudson bomber was shot down an hour and a half before the Pearl Harbor raid. The British thought that they were the target, they tried to send troops into Thailand to their primary defensive positions but they were not allowed there to go by Thailand. The commander did not have the troops go to their secondary positions for 24 hours.

The British did not want to open hostilities, neither did MacArthur in the Philippines but the Asiatic surface fleet with support vessels was redeploying to operate with the other ABDA forces in that area. Admiral Phillips was actually in Manila at that time.

No effective action was taken. What you've described is more or less just what I said about how field commanders were constrained.

[warspite1]

Ships sailing the sea! Impossible! Yes, they have to be refueled and they have to hold well beyond the launch point if aborted. If they're detected at that distance it tells no one anything - they're just "training". The carriers being absent on a Sunday was an exception.

Let's be clear: The Japanese had no issue with ordering their men to strap on an obsolete aircraft loaded with bombs and fuel and to suicidally fly that plane into an enemy ship. if they could do that, a few sea voyages seems really minor.

Reminder: The invasion forces for Malaya WERE detected, long before they arrived. No action was taken by the Allies. The Allies were close to oblivious about Japan's intentions and their C&C was on a very peace-time footing. No field commander had the green light for anything. Action required a long political process.

warspite1

Interesting thoughts on secret missions and warfare. So if being detected can simply be brushed off without alerting anyone, why did Japan bother with secrecy and sailing via the northern Pacific? A naval task force centred on six fleet carriers a day from Pearl... yep that's a training mission if ever I saw one.....

But I notice you make no comment on the carriers and the number of carriers. You brush this off quite airily because the Kido Butai could obviously afford to spend the month of November/December sailing up and down the North Pacific.

You seem fixated on Kamikazes.... strange

I don't think you've missed the point, but willfully don't see a problem in combat troops being endlessly loaded, put to sea for a day or two, then turned around sent back to port, repeat rinse cycle. You have also downplayed the possibility of detection being an issue so no point furthering that.

Warfare is so simple innit?

[warspite1]

All those questions could be answered if you'd play a few wargames on the Pacific War - as I've done. It's doable. The sims say so. I've described how they do it. They take the undefended neighbor islands, then fly zeros (very long range) and Betty bombers into the airfields there (Bettys were torpedo capable). They then have their way with everything else on Oahu and every ship trying to get to/from Oahu. Initially, supplies are delivered by destroyer (as done in several other Jap invasions.) But, as the situation deteriorates for the US, normal supply lines can be established.

warspite1

Sadly I feel we are back to the invasion of Spain territory. If a wargame says it can be done then it can be done right?

And as with Spain, so with Hawaii. No, you've described nothing. You've made a few high level statements, largely divorced from reality, with nothing to support them. Which islands can Zeros reach the Hawaiian islands from? How do those Zeros reach the islands in the first place? Where are the aircraft coming from? What's the timescale for all this manoeuvring?

And all the questions regarding supplying, fuelling, repairing etc still won't go away.

Japanese resources are finite. They have a lot to do - and nothing more important than securing the oil of the NEI. But....

[TulliusDetritus]

Warfare is so simple innit?

“Everything in war is very simple, but the simplest thing is difficult” - Clausewitz