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Should The Japanese Have Followed The Pearl Harbor Attack With A Land Assault?


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#1 On the way

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Posted 26 March 2020 - 0414 AM

Ok guys, I am almost afraid to post another thread here after the last one went 29 pages and 11400 views. LOL. But here goes.

 

Should the Japanese have made contingency plans for an amphibious assault on Oahu, immediately following the Pearl Harbor attack? The attack succeeded beyond what the Japanese had hope for (other then bagging the US carriers), as far as I can see, the way was open for a landing somewhere on Oahu island. The more I looked at it, the more feasible it seems. Some considerations.

 

- The Imperial navy was about 240 miles away when the planes were launched for the first wave. That is about 1 day's sailing to Oahu. If they had put up two more waves on Dec 7th to soften land targets preparatory to a landing the following day, they could in theory be off the coast of Oahu the next morning.

 

- They would have air superiority if they attempted a landing.

 

- They would have a choice of landing beaches throughout Oahu. I am not sure what the US Army strength on Oahu was during the Pearl Harbor attack, but they can't possibly defend all possible landing beaches, especially after the confusion, and casualties from the prior day's attack.

 

- The Japanese had conducted successful landings a few days later throughout SE Asia, so I am inclined to think they have some expertise in this. The level of opposition varied from their landings, but they were all successful in Malaya, Hong Kong, Dutch East Indies, Philippines, etc. There is a case to be made that they would have successfully landed on Oahu too. Especially with big gun support from their Battleships and cruisers, and air superiority. Naval gunfire as well as air superiority would have neutralized any counter attacks from US forces.

 

- They could have embarked a landing force of 15,000 troops, many would have been veterans of the China campaign. By comparison, they invaded Malaya at Kota Bahru with an initial force of about 8,000. They might have succeeded with this initial force. If the Dec 7th attack on Pearl Harbor had gone poorly, this landing force could have turned around and be dropped of at any of the other SE Asia invasion sites as reinforcements.

 

- They might have encountered a neutral or even friendly civilian population, with the largest ethnic group being Japanese of Nissei and Issei generations. Many of whom still speak japanese and have ties with their homeland.

 

- Strategically, this would have been a game changer. The US would have made the re-taking of Pearl Harbor the number one priority. But they would have been denied the use of Oahu as a staging base, and be denied all its ship repairing facilities, etc.

 

- The Japanese would also be in possession of of thousands of American POWs. Any american attempt to re-take Oahu has to account for this.

 

- I don't know how long the Japanese would be able to hold Oahu, given the logistics. But the island's sugar and pineapple plantations could be converted to growing food crops. Water would not be an issue either.

 

My thinking is they probably should have embarked an invasion force, and use it if the attack had gone according to plan on Dec 7th. Just my 2 cents.

 


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#2 RETAC21

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Posted 26 March 2020 - 0459 AM

Ok guys, I am almost afraid to post another thread here after the last one went 29 pages and 11400 views. LOL. But here goes.

 

Should the Japanese have made contingency plans for an amphibious assault on Oahu, immediately following the Pearl Harbor attack? The attack succeeded beyond what the Japanese had hope for (other then bagging the US carriers), as far as I can see, the way was open for a landing somewhere on Oahu island. The more I looked at it, the more feasible it seems. Some considerations.

 

- The Imperial navy was about 240 miles away when the planes were launched for the first wave. That is about 1 day's sailing to Oahu. If they had put up two more waves on Dec 7th to soften land targets preparatory to a landing the following day, they could in theory be off the coast of Oahu the next morning.

 

- They would have air superiority if they attempted a landing.

 

- They would have a choice of landing beaches throughout Oahu. I am not sure what the US Army strength on Oahu was during the Pearl Harbor attack, but they can't possibly defend all possible landing beaches, especially after the confusion, and casualties from the prior day's attack.

 

- The Japanese had conducted successful landings a few days later throughout SE Asia, so I am inclined to think they have some expertise in this. The level of opposition varied from their landings, but they were all successful in Malaya, Hong Kong, Dutch East Indies, Philippines, etc. There is a case to be made that they would have successfully landed on Oahu too. Especially with big gun support from their Battleships and cruisers, and air superiority. Naval gunfire as well as air superiority would have neutralized any counter attacks from US forces.

 

- They could have embarked a landing force of 15,000 troops, many would have been veterans of the China campaign. By comparison, they invaded Malaya at Kota Bahru with an initial force of about 8,000. They might have succeeded with this initial force. If the Dec 7th attack on Pearl Harbor had gone poorly, this landing force could have turned around and be dropped of at any of the other SE Asia invasion sites as reinforcements.

 

- They might have encountered a neutral or even friendly civilian population, with the largest ethnic group being Japanese of Nissei and Issei generations. Many of whom still speak japanese and have ties with their homeland.

 

- Strategically, this would have been a game changer. The US would have made the re-taking of Pearl Harbor the number one priority. But they would have been denied the use of Oahu as a staging base, and be denied all its ship repairing facilities, etc.

 

- The Japanese would also be in possession of of thousands of American POWs. Any american attempt to re-take Oahu has to account for this.

 

- I don't know how long the Japanese would be able to hold Oahu, given the logistics. But the island's sugar and pineapple plantations could be converted to growing food crops. Water would not be an issue either.

 

My thinking is they probably should have embarked an invasion force, and use it if the attack had gone according to plan on Dec 7th. Just my 2 cents.

 

 

There must be a thread archived "somewhere" here were we went in detail around 10-15 years ago. The gist of it is that it wasn't possible. Sure, the US got surprised that morning, but by 9:00 or so, they were on full alert, defences manned and ready and the only undefended beaches were on the North side, exposed to weather and requiring a hump over some sizable mountains to get anywhere. All US military installations were adquately protected by Coast Artillery and AAA, and there were 4 Infantry regiments + the Marines, plus ship crews made available (speaking off memory so I maybe off) so the invasion force would need no less than 2 divisions, which was something the Japanese couldn't support.


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#3 Stuart Galbraith

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Posted 26 March 2020 - 0518 AM

Should have just gone back and blown up the tank farm. That would have achieved most of what they wanted to do.


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#4 Sardaukar

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Posted 26 March 2020 - 0836 AM

Some stuff here:

 

https://history.army...uard-US/ch6.htm

 

Also:

 

Chief of Staff: Prewar Plans and Preparations, Volume 4, Part 1 

 

(can find that in Google Books)

 

MRTGz9v.png​

 

Japan just didn't have capacity to bring enough troops in to overwhelm that sort of force, especially when way too far from supply sources. I doubt there was any IJN/IJA capability ever for multidivision amphibious landing. 


Edited by Sardaukar, 26 March 2020 - 0841 AM.

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#5 Rich

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Posted 26 March 2020 - 1011 AM

Oh dear God nooooooo!


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#6 Stuart Galbraith

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Posted 26 March 2020 - 1122 AM

:P


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#7 Rich

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Posted 26 March 2020 - 1132 AM

Should have just gone back and blown up the tank farm. That would have achieved most of what they wanted to do.

Stop it, we hates you filthy Stuartses, you're going to invoke the wrath of robdabses...


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#8 RETAC21

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Posted 26 March 2020 - 1143 AM

 

Should have just gone back and blown up the tank farm. That would have achieved most of what they wanted to do.

Stop it, we hates you filthy Stuartses, you're going to invoke the wrath of robdabses...

 

 

I mean, it will fail because the Japanese lacked Stukas, Siebel ferries and Kamikaze liners, else it would suceed, surely you agree? :D


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#9 Rich

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Posted 26 March 2020 - 1309 PM

 

 

Should have just gone back and blown up the tank farm. That would have achieved most of what they wanted to do.

Stop it, we hates you filthy Stuartses, you're going to invoke the wrath of robdabses...

 

 

I mean, it will fail because the Japanese lacked Stukas, Siebel ferries and Kamikaze liners, else it would suceed, surely you agree? :D

 

Aaaaaaaaaaargh! You forgot the precision strike Japanese 16 and 18-inch naval guns. And the Japanese Aerial Ninja SNLF Korps. Of course, there's a guy on AHF that beats all that by offering up proposals for million-ton unsinkable battleships and sidelining Sealion for a more practical means...building a siege causeway across the English Channel. I shit you not. And all this even before the effects of social isolation have truly set in.


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#10 glenn239

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Posted 26 March 2020 - 1348 PM

Oh dear God nooooooo!

:D :D :D :D‹ 


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#11 glenn239

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Posted 26 March 2020 - 1411 PM

Ok guys, I am almost afraid to post another thread here after the last one went 29 pages and 11400 views. LOL. But here goes.

 

 

 

The traffic on this site is fading over the years, so isn't 11400 views a good thing?

 

 

 

Should the Japanese have made contingency plans for an amphibious assault on Oahu, immediately following the Pearl Harbor attack? The attack succeeded beyond what the Japanese had hope for (other then bagging the US carriers), as far as I can see, the way was open for a landing somewhere on Oahu island. The more I looked at it, the more feasible it seems. Some considerations.

 

 

Short answer is no.  The Japanese carrier force had its hands full just dealing with the existing situation even after delivering a powerful initial blow.  At Midway, the additional complications of a split mission lead to disaster.  Adding an amphibious assault on the 7th would be beyond the capacity of Nagumo to cope.  

 

 

- They would have a choice of landing beaches throughout Oahu. I am not sure what the US Army strength on Oahu was during the Pearl Harbor attack, but they can't possibly defend all possible landing beaches, especially after the confusion, and casualties from the prior day's attack.

 

 

Oahu is dominated by two mountain ranges, one on the west coast, one on the east coast.  Splitting the island down the middle, a central plain.  The east and west coast were essentially undefended.  Two US divisions guarded the north and south coast, along with a metric shit ton of coastal artillery.  In December, the north coast was pounded by heavy waves, so the forces there should be available to reinforce any threat on the south coast.  

 

The Japanese had conducted successful landings a few days later throughout SE Asia, so I am inclined to think they have some expertise in this. The level of opposition varied from their landings, but they were all successful in Malaya, Hong Kong, Dutch East Indies, Philippines, etc. There is a case to be made that they would have successfully landed on Oahu too. Especially with big gun support from their Battleships and cruisers, and air superiority. Naval gunfire as well as air superiority would have neutralized any counter attacks from US forces.

 

 

Two US carriers were out there, so air superiority was not assured.  The north coast was inaccessible due to surfing conditions.  Of the east and west coasts, one of the two would have had landing conditions, (more likely the west), but landings here were a cul de sac because of the mountain ranges.  Landings on the south shore would run straight into the plentiful coastal artillery and one division, plus Marines and elements of a second division reinforcing.

 

 

- I don't know how long the Japanese would be able to hold Oahu, given the logistics. But the island's sugar and pineapple plantations could be converted to growing food crops. Water would not be an issue either.

 

 

Into 1944

 

 

My thinking is they probably should have embarked an invasion force, and use it if the attack had gone according to plan on Dec 7th. Just my 2 cents.

 

 

And I'm already in hot water for Sealion. :^)  The strategic logic underpinning your conclusions is compelling, but American defenses were of a scale that the Japanese were deterred from the risk.  The operation you outline would not have worked and might have caused KB to have been defeated, similar to Midway.


Edited by glenn239, 26 March 2020 - 1412 PM.

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#12 Rick

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Posted 26 March 2020 - 1744 PM

"- I don't know how long the Japanese would be able to hold Oahu, given the logistics. But the island's sugar and pineapple plantations could be converted to growing food crops. Water would not be an issue either."

 

This may be the easiest to answer as the longest hold out time would be until 1954 due to

 -- GODZILLA !!!


Edited by Rick, 26 March 2020 - 1746 PM.

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#13 Martin M

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Posted 26 March 2020 - 1814 PM

Oh dear God nooooooo!

 

 

you guys love these things.  So just get started.


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#14 On the way

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Posted 27 March 2020 - 0323 AM

 

Ok guys, I am almost afraid to post another thread here after the last one went 29 pages and 11400 views. LOL. But here goes.

 

Should the Japanese have made contingency plans for an amphibious assault on Oahu, immediately following the Pearl Harbor attack? The attack succeeded beyond what the Japanese had hope for (other then bagging the US carriers), as far as I can see, the way was open for a landing somewhere on Oahu island. The more I looked at it, the more feasible it seems. Some considerations.

 

- The Imperial navy was about 240 miles away when the planes were launched for the first wave. That is about 1 day's sailing to Oahu. If they had put up two more waves on Dec 7th to soften land targets preparatory to a landing the following day, they could in theory be off the coast of Oahu the next morning.

 

- They would have air superiority if they attempted a landing.

 

- They would have a choice of landing beaches throughout Oahu. I am not sure what the US Army strength on Oahu was during the Pearl Harbor attack, but they can't possibly defend all possible landing beaches, especially after the confusion, and casualties from the prior day's attack.

 

- The Japanese had conducted successful landings a few days later throughout SE Asia, so I am inclined to think they have some expertise in this. The level of opposition varied from their landings, but they were all successful in Malaya, Hong Kong, Dutch East Indies, Philippines, etc. There is a case to be made that they would have successfully landed on Oahu too. Especially with big gun support from their Battleships and cruisers, and air superiority. Naval gunfire as well as air superiority would have neutralized any counter attacks from US forces.

 

- They could have embarked a landing force of 15,000 troops, many would have been veterans of the China campaign. By comparison, they invaded Malaya at Kota Bahru with an initial force of about 8,000. They might have succeeded with this initial force. If the Dec 7th attack on Pearl Harbor had gone poorly, this landing force could have turned around and be dropped of at any of the other SE Asia invasion sites as reinforcements.

 

- They might have encountered a neutral or even friendly civilian population, with the largest ethnic group being Japanese of Nissei and Issei generations. Many of whom still speak japanese and have ties with their homeland.

 

- Strategically, this would have been a game changer. The US would have made the re-taking of Pearl Harbor the number one priority. But they would have been denied the use of Oahu as a staging base, and be denied all its ship repairing facilities, etc.

 

- The Japanese would also be in possession of of thousands of American POWs. Any american attempt to re-take Oahu has to account for this.

 

- I don't know how long the Japanese would be able to hold Oahu, given the logistics. But the island's sugar and pineapple plantations could be converted to growing food crops. Water would not be an issue either.

 

My thinking is they probably should have embarked an invasion force, and use it if the attack had gone according to plan on Dec 7th. Just my 2 cents.

 

 

There must be a thread archived "somewhere" here were we went in detail around 10-15 years ago. The gist of it is that it wasn't possible. Sure, the US got surprised that morning, but by 9:00 or so, they were on full alert, defences manned and ready and the only undefended beaches were on the North side, exposed to weather and requiring a hump over some sizable mountains to get anywhere. All US military installations were adquately protected by Coast Artillery and AAA, and there were 4 Infantry regiments + the Marines, plus ship crews made available (speaking off memory so I maybe off) so the invasion force would need no less than 2 divisions, which was something the Japanese couldn't support.

 

Sorry, I was not aware there was an archived thread on this topic.


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#15 On the way

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Posted 27 March 2020 - 0324 AM

Some stuff here:

 

https://history.army...uard-US/ch6.htm

 

Also:

 

Chief of Staff: Prewar Plans and Preparations, Volume 4, Part 1 

 

(can find that in Google Books)

 

MRTGz9v.png​

 

Japan just didn't have capacity to bring enough troops in to overwhelm that sort of force, especially when way too far from supply sources. I doubt there was any IJN/IJA capability ever for multidivision amphibious landing. 

Ok, noted.


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#16 RETAC21

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Posted 27 March 2020 - 0335 AM

 

 

Ok guys, I am almost afraid to post another thread here after the last one went 29 pages and 11400 views. LOL. But here goes.

 

Should the Japanese have made contingency plans for an amphibious assault on Oahu, immediately following the Pearl Harbor attack? The attack succeeded beyond what the Japanese had hope for (other then bagging the US carriers), as far as I can see, the way was open for a landing somewhere on Oahu island. The more I looked at it, the more feasible it seems. Some considerations.

 

- The Imperial navy was about 240 miles away when the planes were launched for the first wave. That is about 1 day's sailing to Oahu. If they had put up two more waves on Dec 7th to soften land targets preparatory to a landing the following day, they could in theory be off the coast of Oahu the next morning.

 

- They would have air superiority if they attempted a landing.

 

- They would have a choice of landing beaches throughout Oahu. I am not sure what the US Army strength on Oahu was during the Pearl Harbor attack, but they can't possibly defend all possible landing beaches, especially after the confusion, and casualties from the prior day's attack.

 

- The Japanese had conducted successful landings a few days later throughout SE Asia, so I am inclined to think they have some expertise in this. The level of opposition varied from their landings, but they were all successful in Malaya, Hong Kong, Dutch East Indies, Philippines, etc. There is a case to be made that they would have successfully landed on Oahu too. Especially with big gun support from their Battleships and cruisers, and air superiority. Naval gunfire as well as air superiority would have neutralized any counter attacks from US forces.

 

- They could have embarked a landing force of 15,000 troops, many would have been veterans of the China campaign. By comparison, they invaded Malaya at Kota Bahru with an initial force of about 8,000. They might have succeeded with this initial force. If the Dec 7th attack on Pearl Harbor had gone poorly, this landing force could have turned around and be dropped of at any of the other SE Asia invasion sites as reinforcements.

 

- They might have encountered a neutral or even friendly civilian population, with the largest ethnic group being Japanese of Nissei and Issei generations. Many of whom still speak japanese and have ties with their homeland.

 

- Strategically, this would have been a game changer. The US would have made the re-taking of Pearl Harbor the number one priority. But they would have been denied the use of Oahu as a staging base, and be denied all its ship repairing facilities, etc.

 

- The Japanese would also be in possession of of thousands of American POWs. Any american attempt to re-take Oahu has to account for this.

 

- I don't know how long the Japanese would be able to hold Oahu, given the logistics. But the island's sugar and pineapple plantations could be converted to growing food crops. Water would not be an issue either.

 

My thinking is they probably should have embarked an invasion force, and use it if the attack had gone according to plan on Dec 7th. Just my 2 cents.

 

 

There must be a thread archived "somewhere" here were we went in detail around 10-15 years ago. The gist of it is that it wasn't possible. Sure, the US got surprised that morning, but by 9:00 or so, they were on full alert, defences manned and ready and the only undefended beaches were on the North side, exposed to weather and requiring a hump over some sizable mountains to get anywhere. All US military installations were adquately protected by Coast Artillery and AAA, and there were 4 Infantry regiments + the Marines, plus ship crews made available (speaking off memory so I maybe off) so the invasion force would need no less than 2 divisions, which was something the Japanese couldn't support.

 

Sorry, I was not aware there was an archived thread on this topic.

 

 

It was rather old...


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#17 On the way

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Posted 27 March 2020 - 0347 AM

 

Ok guys, I am almost afraid to post another thread here after the last one went 29 pages and 11400 views. LOL. But here goes.

 

 

 

The traffic on this site is fading over the years, so isn't 11400 views a good thing?

 

 

 

Should the Japanese have made contingency plans for an amphibious assault on Oahu, immediately following the Pearl Harbor attack? The attack succeeded beyond what the Japanese had hope for (other then bagging the US carriers), as far as I can see, the way was open for a landing somewhere on Oahu island. The more I looked at it, the more feasible it seems. Some considerations.

 

 

Short answer is no.  The Japanese carrier force had its hands full just dealing with the existing situation even after delivering a powerful initial blow.  At Midway, the additional complications of a split mission lead to disaster.  Adding an amphibious assault on the 7th would be beyond the capacity of Nagumo to cope.  

 

 

- They would have a choice of landing beaches throughout Oahu. I am not sure what the US Army strength on Oahu was during the Pearl Harbor attack, but they can't possibly defend all possible landing beaches, especially after the confusion, and casualties from the prior day's attack.

 

 

Oahu is dominated by two mountain ranges, one on the west coast, one on the east coast.  Splitting the island down the middle, a central plain.  The east and west coast were essentially undefended.  Two US divisions guarded the north and south coast, along with a metric shit ton of coastal artillery.  In December, the north coast was pounded by heavy waves, so the forces there should be available to reinforce any threat on the south coast.  

 

The Japanese had conducted successful landings a few days later throughout SE Asia, so I am inclined to think they have some expertise in this. The level of opposition varied from their landings, but they were all successful in Malaya, Hong Kong, Dutch East Indies, Philippines, etc. There is a case to be made that they would have successfully landed on Oahu too. Especially with big gun support from their Battleships and cruisers, and air superiority. Naval gunfire as well as air superiority would have neutralized any counter attacks from US forces.

 

 

Two US carriers were out there, so air superiority was not assured.  The north coast was inaccessible due to surfing conditions.  Of the east and west coasts, one of the two would have had landing conditions, (more likely the west), but landings here were a cul de sac because of the mountain ranges.  Landings on the south shore would run straight into the plentiful coastal artillery and one division, plus Marines and elements of a second division reinforcing.

 

 

- I don't know how long the Japanese would be able to hold Oahu, given the logistics. But the island's sugar and pineapple plantations could be converted to growing food crops. Water would not be an issue either.

 

 

Into 1944

 

 

My thinking is they probably should have embarked an invasion force, and use it if the attack had gone according to plan on Dec 7th. Just my 2 cents.

 

 

And I'm already in hot water for Sealion. :^)  The strategic logic underpinning your conclusions is compelling, but American defenses were of a scale that the Japanese were deterred from the risk.  The operation you outline would not have worked and might have caused KB to have been defeated, similar to Midway.

 

Amphibious assault would have been on the 8th, not the 7th. I would imagine coastal artillery and US Army movements to the beach would be under fire from Nagumo's fleet once they were off the Oahu coast on the 8th? IJN cruisers, battleships, etc pounding US army installations in Oahu as well as air superiority by the IJN would have counted for something. Its true the US had a larger force, but they were not season veterans like the Japanese force likely is. The 2 US carriers you mentioned, I recall had already dropped of their planes at Midway. Were they still a threat without an air wing on board? I do agree after reading the comments here, this landing would not have been feasible for the Japanese.


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#18 DougRichards

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Posted 27 March 2020 - 0348 AM

Checking over

 

https://en.wikipedia...ecember_7,_1941

 

Shows that there were 21 undamaged USN destroyers after the attack.  There were also 4 cruisers available for action.

 

Sure, not a huge flotilla overall, but would have made landings costly.


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#19 Stuart Galbraith

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Posted 27 March 2020 - 0500 AM

They could have dug a tunnel.....


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#20 RETAC21

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Posted 27 March 2020 - 0502 AM

Brought the olde thread back to top. It was one of the last threads were King contributed.


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