Lets just pretend they had some capability.

lwd, thanks for the reply.

I see that you have chosen to cut to the heart of the matter without wasting time on all of that strategic "stuff".

I like you already.

On the assumption that Yamamoto is actually given "free reign" command of the IJN's Hawaiian strikeforce AND troop support from the IJA ...

Point by point ...

How in the world can the Japanese get that close to Hawaii without being seen?

Exactly the same way as they did historically, with some additional daring.

Please emember that night on Oahu is 12.5 hours long at that time of year with sunrise at 0606 and sunset at 1735.

Prange's "At Dawn We Slept" reports that three Washington approved Japanese repatriation passenger liners passed thru Oahu's Honolulu Harbor in the two months prior to Dec.7'41. Japanese agents on board reported to Tokyo that United States Army Air Force (USAAF) scout planes were first seen 200 miles offshore from Oahu and that the first USAAF attack bombers only "buzzed" the cargo-liners at 100 miles offshore. Yoshikawa reported as late as 1800 on Dec.6'41 that the USN was still NOT flying any long ranged seaplane searches out of Oahu. Thus the OTL Japanese assumed that they could safely approach to within 200 miles
of Oahu WITHOUT being spotted by American air recon at dawn. It was NOT just a random pick that saw the OTL Nagumo launch his historical air strikes from 230 mile NE of Pearl Harbor. The OTL Japanese chose that distance based on the known US air recon radius of 200 miles.

My ATL Japanese would do the same by crossing that 200 mile line at dusk on Dec.6'41. A run in at 20+ knots for 12.5 hours gives them a travel distance of 250+ miles before sunrise. Up to 312 if they bump up to 25 knots as most IJN warships could easily do. They didn't need either.

Save just off of the Pearl Harbor entrance channel (the gateguard destroyer USS Ward and others), there was no USN patrol around Oahu at all. None. And Yoshikawa, who regularly rented civilian aircraft for "sight seeing" trips all over Oahu, would have easily reported such to Tokyo.

Who was going to see my ATL Japanese invaders rushing in thru the peacetime Satuday "liberty night" darkness ?

Despite Washington's alerts, no one on Oahu was even looking.

Since my ATL Japanese are not blessed with hindisght, I include for them an additional distraction JUST IN CASE an American or two on Oahu was not "asleep at the wheel" as most there were on Dec.6-7'41.

Prange's book also reports that a 4th OTL Japanese fast repatriatin cargo-liner, the big 17,500 ton 20 knot+ Tatuta (also spelled Tatsuta) Maru (TM) was Washington approved for yet another Honolulu port call on Dec.9'41 while on her way between Yokahama and San Francisco. In reality hers was a deliberate Japanese deception mission designed to lull Oahu's defenders into a false sense of security. What nation would send a passenger ship full of civilians to an island that they palnned to attack ?? Historically she went radio silent and turned back to Japan at 0005 on Dec.7'41.

In my ATL she would have been scheduled instead for an 0530 Dec.7'41 arrival at Honolulu and would have led (by 60 or so miles) my ATL Japanese strikeforce across the northern Pacific, sending coded radio messages for her civilian passengers, all the way. A fast moving radio beacon that the American radio direction finding (RDF) types could easily follow all the way from Japan to Hawaii. Never once dreaming that a powerful Hawaii invasion force followed close behind that now scouting cargo-liner.

Given their lack of experiance in invasions how are they going to possibly get major forces ashore before the US can react?

As I just previously posted, the OTL Japanese had been doing 2 division landings on the Chinese coast since 1932 so they were NOT at all inexperienced. Against undefended beaches anyway.

My ATL 1st landing wave (1LW) would be comprised of only 9 Japanese fast troop-carrying vessels hauling some 11,500 lightly equipped troops.

Three big fast cargo liners would each host a regiment (of 3,400 men) of Japan's 7th Infantry Division. That formerly crack division had been badly mauled by Soviet firepower at the Nomonham battles in 1939 but had been resting/refitting/training in reserve status in Japan ever since. They were EAGER to restore their sullied battle honor and had time to train for both beach landings and jungle/mountain combat on Oahu.

On two of the three NYK Lines cargo-liners, their regular lifeboats would have been replaced with three sizes of daihatsu landing barges (30 men, 70 men or a light tank, 125 men or a medium tank) that could be lowered (already fully loaded) over the liner's side by lifeboat davits and their cargo booms for fast troop unloading. Only two full round trips to the beach would be required by each daihatsu to empty the IJA troops off of each liner. More trips for the regiment's heavy equipment to be sure but at least the IJA's light infantry would already be safe from American air attack, coastal artillery fire or naval gunfire, after sunrise.

Also along would be 6 OTL converted ex-DDs, called "patrol boats" by the OTL Japanese, 4 of which would carry 2 daihatsu landing barges and 250 JSNLF troops each and 2 smaller versions each with 1 daihatsu landing barge and 125 JSNLF troops aboard. These would be the "distraction troops" (DTs) to be landed on several of Oahu's shorelines to cause havoc and confusion for General Short's US Artmy defenders. Which shoreline would the surprised Sunday morning peacetime American defenders rush to when ALL were reporting dawn landings and combat ??

Another Japanese infantry division would land on the following (Dec.7-8'41) night, provided that safe landing areas had already been secured by the 1LW.

Thus, my scenario includes a distraction or two designed to keep Oahu's defenders busy and blinded, as follows ...

What kind of support do you think they could assign to this invasion?

I had in mind 8 of the 10 battleships of the Combined Fleet (CF).

Plus escorts to include 1 CV(L) loaded only with Zeros for CAP duties overhead.

Go big or stay home, I always say.

The other two BBs (the older, slower ones) are still assigned in distant support of their Southern Operation, as two were in the OTL.

Their main gun ammo loads would be roughly 75% bombardment HE and 25% anti-warship AP just in case the USN's Pacific Fleet somehow received an advanced warning and sortied for a "Decisive Battle" at sea somewhere off of Hawaii. Or in case the KB's warplanes were not able to complete their anti-warship target assignments within Pearl Harbor. The CF battleships had a 4 knot fleet speed advantage over the older USN battleline (with 30 IJN submarines equipped with WORKING torpedos in close support) so that the CF could stay just out of range as their submarines and the KB's warplanes whittled away at the American Fleet's strength.

Bold I know but it is better to control the time and place of the "Decisive Battle" yourself than to allow your enemy to do so. As per that Mahan source that was just recently posted upthread here.

I'd also like to include the just built Yamato as IJN battleship #9 but to do so I'll need general agreement here that she might have been completed and her crew trained a few months earlier than historically by the shifting of most of her sister Musashi's construction crews over to work on her, in secret. Considering that the OTL Americans still didn't know the real size of those 18.1" main guns in mid-1944, I don't think an earlier Yamato completion to be too much of a "stretch" but your/others opinins may differ. I hope that we can "talk about it". My ATL scenario is NOT dependent on Yamato's presence off of Oahu's shores but she sure would make things easier for my ATL Japanese if her big guns were there.

Yes, I know that 4 additional civilian tanker to fleet oiler (capable of underway refueling - UWR) conversions ( 8 OTL + 4 ATL = 12 now) will be required to fuel the KB + CF across the northern Pacific. In the OTL there were some 49 available, at least until the NEI's oil was available again.

In the OTL, the Combined Fleet did nothing much save cruise slowly out around the Bonin Islands and then back to the Inland Sea in VERY distant support of Nagumo's Kido Butai (KB) carrier strike force. By using the same deceptive radio broadcasting techniques to "hide" them as were historically used by the Japanese to "hide" the KB during it's journey toward Hawaiian waters, I believe that they would arrive there just as undiscoverd as the KB was, historically.

A regular stream of faked radio traffic could easily be genarated to make the listening American code-breakers believe that the CF's battleships were engaged in thier normal gunnery practise exercises in the Bonins. Thus easily explaining any intell reports of IJN BBs loading more main gun rounds that might have reached American ears.

Getting the invasion force you have suggested anywhere near Hawaii without being detected is highly problematic. Let's look at the problems:

1) The transports have to leave well in advance of the fleet or the whole fleet has to travel at the transport speeds. This has a number of implications. One of the most important is it leaves a lot more time for the force to be discovered. It's also a much bigger target as far as observation is concerned.

2) When the battle fleet "dissapears" warning bells are going to be going off all over the place. The longer they are at sea the harder the allies are going to be looking for them.

3) Then there's the problem of fuel usage. Japan does have enough fuel for this op but it's going to require most of their tankers and many of the ships will have to refuel at sea some several times.

4) In addition to their being extra searches everyone is going to be quite a bit more alert. One of the things that helped at PH was that the impression was that sabotage was the main thing they had to worry about. If the Japanese battle fleet has been unaccounted for for weeks that perception is very likely to change.

5) Consider also the code breaking situation. The Japanese naval code had been compromised but they changed it just before the PH op. If they change it according to RL then there's a very good chance some details are derived due to the op getting underway weeks earlier. If on the otherhand they change just before the op starts there is a chance that the US will have broken the new code at least to some extent before the strike and gotten some valuable info that way. The absence of the battle fleet will likely spur efforts in this regard.

As for the Japanese practicing landings in China. How long did it take them to get forces ashore? My understanding is Sakai was amazed at how fast the US was doing it at Gaudacanal. At least in the copy of the Caiden book it is stated he thought that the US was doing this much faster than the Japanese. The practice landings in China would also not have been in heavy surf, in areas with coral reefs, vs land, sea, and air opposition. I'm pretty sure the US had at least a small armored force on Hawaii as well as numerous coastal batteries (covering the likely invasion beaches). I certainly wouldn't want to try a night invasion in this situation and or bring my transports in range of shore batteries.

My impression is that if Yamamoto were given a free hand this is the last thing he would have tried. If he had elected to try it given his (and Japan's) proclivity for overly complex plans that tended to underestimate their opponents doing something stupid I wouldn't give them a very good chance of success.

O yea of little faith, would I do that to you ?

You may not like my ATL Hawaiian scenario but when you consider the historical 6 months long Pacific romp of the Japanese all over the Allies, even you would have to admit that the Nipponese had some good capability at both island and amphibious warfare.

They hit fast and they hit hard so as to always keep their opponents off balance. Without allowing time to recover or regroup. "Shoesting" invasions were the norm for them, living off the land until supplies were eventually brought forward, was the expected.

Nine (still onging) years of heavy combat against the Chinese AND the Russians had tightened up the IJA while the peacetime garrison Americans had fought nothing more than tiny "banana republic' police actions with the Marines only, since 1918, some 23 lazy YEARS before.

Until the over-confidence set in, the OTL Japanese had lots of capability, and proved it, time after time, when the Allies couldn't even hold.

dabrob you have put quite a lot of thought into this. The only problem is that Japans ground forces and logistics chain were committed to Maylasia, Singapore and the Phillipines.

Bottom line is that if Japan thought that a ground invasion of Hawaii was feasible they would have done it. AND If they thought a ground invasion of the Hawaiian Islands was feasible why didn't they just invade the mainland US?

Bottom line is that Pearl Harbor was beyond their capabilities to support and there is no way Japan could have held the islands. IF they would have invaded and diverterted resources to capturing and defending Hawaii then the war would have been over in late 1943 or early 1944 and Berlin would have gotten "Fatman" and Heidleberg would have gotten "Littleboy".

Logistics.........you have to able to support your forces on the ground

__________________
"Logos, Philos, Arete"

Its worse than so far suggested:

First, what other invasion does Japan give up to invade Hawaii? They have limited transport available are were using everything they had in the OTL elsewhere.

Next, the largest invasion the Japanese managed to stage was two reinforced infantry divisions in size. This requires about 100 transport ships to haul. So, that would be the approximate maximum size of the forces the Japanese could land in Hawaii.

Hawaii has some of the heaviest coastal defenses of anywhere in the US. Coastal artillery ranges up to 16" in size and those guns outrange anything the Japanese have. Many are in heavy fortifications as well and largely immune to return fire.

The US has two full infantry divisions on Hawaii, along with supporting troops. The Marines have a regiment I believe along with at least one defense battalion like the one on Wake or Johnson Islands.
Worse, the US still has several hundred aircraft after the initial attacks. In addition, most of the US fleet is still intact and now at sea. The US still has three carriers whose locations are unknown.

Bottom line is that Japan might have tried this if they gave up going for say, Malayia and the Dutch East Indies to free up the necessary shipping and manpower to do it. Then, they would be looking at heavy losses in ships, manpower and, material to take the island. They likely would gain little in usable resources beyond sugar cane and pineapples as between US sabatoge and the general fighting most of the useful infrastructure would be demolished.

So, even if they somehow miraculously won and took Ohau they are now faced with a weakened fleet, no means to regularly supply their troops there, a hostile population, and the eventual defeat and reconquest of the island(s) taken by the US. In addition, the loss of not conqueroring the DEI and Malaysia will cripple their economy at home.

This is just a major losing proposition for the Japanese.

lwd, thanks for your quick response,

Getting the invasion force you have suggested anywhere near Hawaii without being detected is highly problematic. Let's look at the problems:

1) The transports have to leave well in advance of the fleet or the whole fleet has to travel at the transport speeds. This has a number of implications.

Historically the KB travelled at 14 knots but averaged only 11 due too refueling needs. My 1LW has 9 ships, each capable of 20+ knots. I see no problem.

One of the most important is it leaves a lot more time for the force to be discovered.

By who (whom ?) ? There was no one out in the northern Pacific at that time of year to see them and in the OTL Nagumo had orders to quickly sink anyone that stumbled across his strikeforce. I see no problem.

It's also a much bigger target as far as observation is concerned.

What difference does size make when there is no one else out there to see them ? I see no problem.

2) When the battle fleet "dissapears" warning bells are going to be going off all over the place. The longer they are at sea the harder the allies are going to be looking for them.

If you would re-read my previuos posting you will see that my ATL Japanese will attempt to make the Allies believe that the CF is engaged in gunnery training in the Bonin Islands. I see no problem.

3) Then there's the problem of fuel usage. Japan does have enough fuel for this op but it's going to require most of their tankers and many of the ships will have to refuel at sea some several times.

My previous posting indicates that 12 instead of 8 tankers would need to be converted, in secret, to UWR capability. I see no problem.

4) In addition to their being extra searches everyone is going to be quite a bit more alert. One of the things that helped at PH was that the impression was that sabotage was the main thing they had to worry about. If the Japanese battle fleet has been unaccounted for for weeks that perception is very likely to change.

Bonin Islands. I see no problem.

5) Consider also the code breaking situation. The Japanese naval code had been compromised but they changed it just before the PH op. If they change it according to RL then there's a very good chance some details are derived due to the op getting underway weeks earlier. If on the otherhand they change just before the op starts there is a chance that the US will have broken the new code at least to some extent before the strike and gotten some valuable info that way.

Historically the Japanese removed transmitter keys and shoved folded paper between the contacts to ensure that there were no accidental KB radio transmissions during the approach to Oahu. My Hawaii invasion force would do the same.

With the added bonus of having the American approved Tatuta Maru scouting out ahead. Any radio signal "leak" from the Hawaii invasion group would just be atributed, by any listening RDF Americans, as yet another TM origin civilian radio message.

The absence of the battle fleet will likely spur efforts in this regard.

Not absent. At gunnery practise in the Bonin Islands.

As for the Japanese practicing landings in China. How long did it take them to get forces ashore? My understanding is Sakai was amazed at how fast the US was doing it at Gaudacanal. At least in the copy of the Caiden book it is stated he thought that the US was doing this much faster than the Japanese.

By the time of Guadalacanal the Americans were using Higgens boats and alligators to bring "everything but the kitchen sink" lavish levels of supply, ashore. OTOH my ATL Japanese invaders would be light infantry on a "shoestring" logistics plan of living off of the land on Oahu.

The practice landings in China would also not have been in heavy surf, in areas with coral reefs, vs land, sea, and air opposition.

They were hardly practise landings. Combat was often entered within a mile or two of the surfline crossed.

Please remember that Oahu's peacetime civilian radfio stations broadcast 6 times a day marine weather forcasts for the benefit of the 400+ Oahu fishing sampan fleet. My ATL Hawaii invasion force would also be listening to those forcasts as they neared Oahu so as to be able to choose landing beaches not hampered by high surf.

I'm pretty sure the US had at least a small armored force on Hawaii as

JUst a single company of 12 early versions of the M5 Stewart light tank, easily stopped by the 6x47mm horse drawn AT guns that were a vital part of a Japanese regiments's TO&E.

well as numerous coastal batteries (covering the likely invasion beaches).

There were indeed lots of Coastal Atrtillery Corps (CAC) shore batteries on Oahu but they were mostly placed to cover Mamala Bay to the SW of Honolulu and the Pearl Harbor entrance channel. The 1940 Americans had budgeted to build shore batteries to cover Kaneohe Bay but by Dec.7'41 none had been yet built.

In addition the US Army defenders of Oahu had several 8" railway guns and a host of 155mm GPF artillery pieces emplaced for shore defence work but they were habitually returned to their inland depots over the weekend. General Short was afraid of sabotage, remember. As I'm sure that you know, Dec.7'41 was a Sunday.

I certainly wouldn't want to try a night invasion in this situation and or bring my transports in range of shore batteries.

Trying it on Oahu at any time other than night would be virtually suicidal.

If given a free hand Yamamoto wouldn't have tried it.

I agree completely since Yamamoto knew that Japan couldn't possibly win a Long War against an industrial giant like the US. He only insisted on hitting Pearl Harbor when it became apparent that his political masters were insisting on a Pacific War with America.

My ATL scenario supposes that he had been given a "free hand" to do his best to force a Short War with the Americans rather than a Long one.

If he had elected to try it given his (and Japan's) proclivity for overly complex plans that tended to underestimate their opponents doing something stupid I wouldn't give them a very good chance of success.

You are certainly entitled to your own opinion but I intend to try to change that here.

formerjughead, thanks for your comments,

dabrob you have put quite a lot of thought into this.

More that a few hours of research too.

The only problem is that Japans ground forces and logistics chain were committed to Maylasia, Singapore and the Phillipines.

That is why I suggest that Luzon, Guam, Wake and the Gilberts be left behind to "wither on the vine" well behind new Japanese frontlines.

Bottom line is that if Japan thought that a ground invasion of Hawaii was feasible they would have done it.

True enough but if that is really your "only history is allowed" point of view, why is it that you read or post to a "What IF" discussion board ?

AND If they thought a ground invasion of the Hawaiian Islands was feasible why didn't they just invade the mainland US?

California had lots of oil but was already attached to an industrial giant of a country called America which (at least back then) seemed to like having it around.

Not so much nowadays.

OTOH the NEI was awash with oil, was closer to Japan and had a motherland just taken over by Japan's allie, Germany. The NEIs seem a more rational choise to me. Invading Hawaii (and capturing 500,000 hostages) is just a way of getting peacetable "bargining chips" to convince American to agree to an early ceasefire (before the Essex class carriers arrive) and a short Pacific war.

Bottom line is that Pearl Harbor was beyond their capabilities to support and there is no way Japan could have held the islands.

If you had actually read my previous postings you would know that I do NOT intend that my ATL Japanese will keep Hawaii but rather will try to trade it quickly back to American in exchange for a short Pacific War and ownership of the NEI's oil.

IF they would have invaded and diverterted resources to capturing and defending Hawaii then the war would have been over in late 1943 or early 1944 and Berlin would have gotten "Fatman" and Heidleberg would have gotten "Littleboy".

I disagree but that matters little to the topic of discussion here.

Logistics.........you have to able to support your forces on the ground.

Reading ........ I have already stated that I can free up 1,680,000 tons of Japanes shipping and 49 otherwise idled tankers to provide logistical support for an ATL Japanese short/medium term effort against Hawaii.

T. A. Gardner, thanks for stopping in,

With 4,300+ posts you must be one of the "heavy hitters" posting here ?

Its worse than so far suggested:

For the American defenders of Oahu, yes it is. My ATL Oahu invasion plan is nowhere near being fully rolled out yet. Let alone explained in detail.

Much like my income tax situation.

First, what other invasion does Japan give up to invade Hawaii?

As already typed, Luzon, Guam, Wake and the Gilberts.

They have limited transport available are were using everything they had in the OTL elsewhere.

As already typed several times, I can free up 1,680,000 tons of Japanese shipping AND 49 idled tankers for short to medium term use against Hawaii. At least until the NEI's oil starts to flow once again.

Next, the largest invasion the Japanese managed to stage was two reinforced infantry divisions in size.

MIne will be two unreinforced infantry divisions AND all of the heavy artillery that the OTL Japanese historically used on Luzon against Bataan and Corregidor etc.

This requires about 100 transport ships to haul. So, that would be the approximate maximum size of the forces the Japanese could land in Hawaii.

Since I have found that 10,200 fighting men could be moved to Oahu by just 3 big 17,000 ton fast cargo-liners, I don't agree with your total of 100 being required. But then, it really depends on the size and types of the vessels involved doesn't it ?

Hawaii has some of the heaviest coastal defenses of anywhere in the US.

No question. The historical problem was that at night and on weekends, Oahu's CAC defenses were historically mostly blind. I'll explain later.

Coastal artillery ranges up to 16" in size and those guns outrange anything the Japanese have.

True for three CAC batteries only.

The 2x16" guns of Battery Williston, for the 2x12" guns of Battery Closson and for the 2x16" of Battery Hatch.

However it must be pointed out that beyond the horizon fire was possible only in daylight, with the aid of airbourne or mountaintop spotters with both line-of-sight to Japanese targets AND communications with the long range capable CAC batteries. Night or the loss of air superiority to the invading Japanese would partially blind these American "big guns". Should Japanese light infantry take the "high ground" from the stunned and surprised US Army defenders, then the CAC's guns would be largely out of the fight.

Many are in heavy fortifications as well and largely immune to return fire.

Yes and no. In heavy concrete fortifictions largely proof against direct, flat trajectory naval gunfire, certainly.

Since they were not yet casemated and thus were completely open to the sky however, all were extremely vulnerable to KB diveombing and to high angle "plunging fire" from IJN warships recently (1934+) retro-fitted with high angle fire main guns.

Also to be noted was that many of Oahu's CAC pieces were old and of short range. The "disappearing" type mounts were also of very limited traverse and could NOT send shells over Oahu's two mountain chain backbones.

The US has two full infantry divisions on Hawaii, along with supporting troops. The Marines have a regiment I believe along with at least one defense battalion like the one on Wake or Johnson Islands.

I do have an ATL Japanese plan in mind for them but you won't like it.

Have you ever imagined the effect of spotterplane adjusted 16" and 14" battleship HE shells arriving just after dawn on two divisions worth of still sleeping troops tightly clusterd together within a lightly built four storey barracks complex (the Quadrangles) located in the centre of Oahu ? On a base that also contained the vast majority of their vehicle parks, light weapons armouries, artillery parks and chemical weapons stockpiles.

Such would be my ATL solution for just after the 0606 sunrise on the morning of Dec.7'41. Yet another auspicious "rising sun" situation for the Japanese Empire.

With that type of a supposedly peacetime Sunday morning "wakeup call", I'd not expect much US Army resistance at any of the ATL Japanese landing beaches. While it would most certainly NOT be of "precision guided weapon" accuracy, the IJN wold be able to walk 16" and 14" rounds back and forth across that barracks area for just as long as the KB's Zero fighters could protect the slowly circling CF spotter biplanes.

All day long comes to mind.

Firing over the Koolau Mountain range of eastern Oahu from just offshore of Kaneohe Bay, the 8 IJN battleships of the CF would target Schofield Barracks (2), the warplanes parked wingtip-to-wingtip at Wheeler (1) and Hickam Fields (1), Honolulu's Fort SHafter - the HQ of general Short (1) and the Aliamanu Crater Ammunition Depot (1), leaving two uncommitted as "spares" for Yamamoto's use later in the day. Depending on the successes achieved by the (earlier than historical) KB air strikes on Pearl Harbor, they migh also be used to rain AP destruction down on any US warships seen to be seen trying to transit the Pearl Harbor entrance channel. An American blockship or two sunk there would be a good thing for Japan in the short term.

Yamato's 9x18" guns would just make it worse for the Americans.

Worse, the US still has several hundred aircraft after the initial attacks.

But flyable ? Nah. Not after my CF battleships pound their airfields just after dawn too.

IIRC the Americans only had 360 odd to begin with and many of those were obsolete for combat purposes. To say that Oahu "still has several hundred after the initial attacks" is not a true representation of the very limited opposition in the air that my KB's ATL 3rd strike would face.

Yes, there is a portion of my ATL scenario dedicated to a 3rd air strike on Dec.7'41 also. More later.

In addition, most of the US fleet is still intact and now at sea.

How so ? Or is that other Enterprise using those teleporter beams again ?
i do so hate it when Kirk interferes.

The US still has three carriers whose locations are unknown.

From an ATL Japnese PoV, quite true, however I reserve 50 torpedo armed Kates on the KB's 6 carriers from the 3rd strike, just in case one or more "turn up" on the afternoon of Dec.7'41.

Bottom line is that Japan might have tried this if they gave up going for say, Malayia and the Dutch East Indies to free up the necessary shipping and manpower to do it.

I have previously listed Luzon, Guam, Wake and the Gilberts instead, along with the use of 7th Infantry Division reserve troops from the Japanese Home Islands.

Then, they would be looking at heavy losses in ships, manpower and, material to take the island.

War just sucks doesn't it ?

I note once again that the OTL Japanese walked all over the Allies for 6 months of the Pacific War without taking the level of losses that you suggest here.

They likely would gain little in usable resources beyond sugar cane and pineapples as between US sabatoge and the general fighting most of the useful infrastructure would be demolished.

I have never claimed otherwise but do you really not see the potentails ?

Hawaii is not to be invaded for the resources that are locted there but rather to deny it's use to the United States:

Without Hawaii's runways, no US warplane has the range to fly trans-Pacific to reinforce Allied holdings closer to Japan.

Without Pearl Harbor, American submarines will burn 5,000 miles more of their fuel just to reach Japanese SLOC lanes, thus shortening their "on station" durations and results.

Without immediate access to the PH or Honolulu fuel stockpiles, the USS Enterprise and her escort group runs dry at about 2300 on Dec.8'41. The nearest American UWR capable fleet oiler is the slow USS Neches then plodding along at 9 knots towards Oahu, some 1,200 miles to the NE. The only real question is, do IJN submarines or KB warplanes find her drifting on Dec.9'41, first ? If not ordered by Adm. Kimmel to attack the KB or CF, the Lexington TF and her 17 obsolete Buffalo fighters can probably reach the Neches for fuel and thus survive to fight again on another day.

The loss of the UWR capable fleet oilers USS Neosho and USS Ramapo within PH furtyher cripples ALL of the USN's Pacific operations for several months, until replacements can be brought in from the USN's Atlantic Fleet via the Panama Canal. Some Pacific Fleet refugees from PH who otherwise escape are caught drifting, also out of fuel, before they can reach the safety of US West Coast ports some 2,400 miles away.

The 20,000 or so sailors of the USN's Pacific Fleet who historically formed the cadre training crews of the eargerly waited new US warship construction classes, now won't. Those new Essex class carriers will now take MUCH longer to get ready for action against the Japanese Empire.

Instead, they are drowned in naval combat off of Hawaii or are being worked to death inside of Japanese work camps on the Hawaiian Islands. Those of higher rank are shipped back to Japan proper for none too gentle "questioning" while those with family also captured on Oahu face an entirely different form of hell on earth. Either work (and hard) for your Japanese conquorers or watch as your family menbers ar used for IJA bayonet practise, one by one.

A captured Hawaii means that examples of the latest US warplanes and weaponry are available, with manuals, spares and trained mechanics at hand to fully explain their secrets to Japan's technical experts. Who woun't take kindly to silence or lies when they have asked a question.

Ditto for America's latest radio and radar secrets. Japan's war fighting ability takes HUGE leaps forward.

Ditto as the Japanese explore the ruins of the radio intercept station HYPO found in the basement of Kimmel's Pacific Fleet HQ. Suddenly Japan KNOWS that it's codes have long been broken and a HUGE American advantage disappears. Or, are the Japanese smart enough to use the discovery to feed the Americans with carefully crafted "disinformation" messages to be used in setting up their own traps for surviving USN warships ? Such techniques could certainly enable the ATL Japanese to entice a counter-attacking US Atlantic Fleet into a deadly trap somewhere off of Hawaii.

Do you really think that FDR would consider 500,000 such American hostages to be of so little value ?

Pineapples and sugarcane ?

Who gives a crap about those ?

Hawaii was FAR more valuable than that.

Finally, the morale consequences to the American body politic would be stupendous, to put it mildly.The US voters would demand heads on platters. Could even FDR weather the resulting firestorm ? I'd think not once word got out that HE had fired Admiral Richardson for suggesting that his move of the Pacific Fleet to Oahu was NOT a good idea.

So, even if they somehow miraculously won and took Ohau they are now faced with a weakened fleet,

I'd have to think that the Japanese and American fleeets would now be much closer to parity than they had ever been before in history.

no means to regularly supply their troops there,

Like I've typed before, 1,680,000 tons of shipping could have been freed up for Operation Hawaii.

a hostile population,

Considering that 40% of Hawaii's population was of Japanese ethnicity, I think that you greatly exaggerate.

and the eventual defeat and reconquest of the island(s) taken by the US.

Granted, the USN's Atlantic Fleet WILL certainly try but I am not confident of their success without benefit of their historically secret Japanese code breaking ability. I'd predict an even fight that could go either way depending on pure luck. Certainly the winner would dominate the Pacific in the short term.

However, to that must be added the effect that a now unchecked German Navy would have on Allied efforts in the Atlantic and on the oil routes of the Caribbean.

Would the American counter-attack on Hawaii cost the UK and Russia their Lend/Lease lifelines ?

Finally, after decades of planning, a Mahanian "Decisive Battle" indeed.

In addition, the loss of not conqueroring the DEI and Malaysia will cripple their economy at home.

I see no compelling reasons that these territories would not fall as per the OTL.

This is just a major losing proposition for the Japanese.

It is true that nothing much trumps an A-bomb but then, way back in December of 1941, nobody knew that such a weapon would even work.

Sloniksp, you asked,

Lets imagine, that the 40-50k Japanese soldiers cramped in their vessels managed to somehow land in Hawaii undetected. Then what? Even if they had captured Honolulu what then ?

I think that I've already responded to most of your posting's items in other of my responses but here you raise an Oahu issue that I am still wrestling with.

Once Oahu was invaded and sizable Japanese forces were ashore, what combination of events, in your opinion, would cause General Short to surrender his command ?

I came up with 6 possibilities:

1.) The destruction, fall or blockade of Oahu's only three deep water ports (Pearl Harbor, Honolulu Harbor and the Port of Kaneohe) thru which American reinforcement and resupply must come ?

2,) The Japanese capture of the City of Honolulu, the home of 200,000 of Oahu's then population of 260,000 ? Or, would Short "fight to the last civlian" ? Unlikely I'd think since many living there were the military families of the USN/US Army's troops seving on Oahu.

3.) To the first use of chemiical warfare on Oahu ? Neither the Americans nor the Japanese had ever signed the 1925 Geneva restrictions on the use of chemical weapons in wartime so either could be the first user. Historically the Americans had a large stockpile of chemical weapons already stored on Oahu (at Schofield Barracks) but as of Dec.7'41 had distributed only non-functional training gasmasks to their Hawaiian Island troops. Their civilian poulations had NO masks at all and no proper training in their use even if some were somehow distributed. There were NO children's or baby sized masks available or stockpiled at all.

4.) When the last of the American warplanes/airfields were destroyed/captured thus granting the Japanese invaders unchallenged control of Hawaiian skies ?

5.) When the food/water/ammo ran out ?

6.) When the total destruction of the USN's Pacific Fleet within it's Pearl Harbor base meant that General Short could no longer carry out his primary mission orders of defending that Fleet's home base ?

Historically MacArthur left Manila as an uncontested Open City so as to minimize civilain casualties there but Manila was a Philippine city, NOT an American one.

Personally, I lean towards option #2 since the infamous Japanese Army's 6 week long "Rape of Nanking" began just four short years previous on Dec.9'37. The total deathtoll will never be accurately known but seems to hover somewhere between 100,000 and 300,000 souls.

Had the American defenders of Oahu continued to resist once Honolulu's 200,000 civilians were in IJA hands, the historical parallels would be just too horrific for General Short to ignore, IMO. Especially in light of a Nanking reminder from the IJA commander on the ground in Honolulu.

What are your thoughts on this rather disturbing surrender issue ?

I'll give you one thing; you are certainly well thought. The one thing you are missing is that Japan attacked Pearl Harbor to sink the Aircraft carriers. The American Carriers are key to Japan holding any real estate in the Pacific.

As soon as the Japanese even looked like they would try to occupy Hawaii, for even a short period, every US Naval resource would have been allocated to the defense of the Islands.

You propose that Japan occupies Hawaii for a short time ans uses it as a bargaining chip..........wouldn't happen.

Guam, Midway and Luzon would not wither on the vine they would be supplied through the Phillipines, Singapore and Australia. Japan could not hold Singapore without controlling the Phillipines.

__________________
"Logos, Philos, Arete"

I have been reviewing my copy of Layton's "And I Was There" and can find nothing to support your assertions. Layton says on Page 383;

"The original goal of the second phase had been the consolidation of Japan's island defense system in the Pacific for operations against the American fleet. After 'a strategic situation of long-term invincibility' had been established according to the Japanese strategic master plan, the plan's ambitious third phase called for the 'capture of Hawaii and the outlying islands, attack on the United States, Canada, Panama Canal, as well as against Central America until the United State loses it's fighting spirit and the war can be brought to a conclusion.'"

In fact, the Japanese never achieved their "Second Phase" objective of "long-term invincibility" for their defensive perimeter, and never produced any detail plans for Yamamoto, or anyone else, to attack Alaska, Hawaii, or the West Coast of the US. These were all fantasies in the minds of Japanese long range planners, as the Japanese had not the slightest capability of successfully projecting their military power to any one of these objectives. The Aleutians operation (Operation AL), according to H.P Willmott, in "The Barrier and The Javelin" was simply to block a possible advance of the US military down the Aleutian island chain with the intent of attacking the Kuriles and northern Japan. On Page 91, Willmott says;

"The immediate objective [of Operation AL] was to secure the the condition -- the neutralization of Dutch Harbor -- whereby the landing operations could be carried out. The Combined Fleet was concerned that in time the Aleutians might be developed by the Americans into a staging post for major operations. It was determined to secure what it saw as blocking positions on the line between Dutch Harbor and the Kuriles and Hokkaido."

In other words the Japanese Aleutians operation was purely defensive in nature and not some prelude to a grand offensive against the continental US.

The idea that some grandiose "Third Phase" plan of operations existed in which the Japanese would launch attacks against impossible objectives on the US West Coast, Central America, and the Panama Canal, is belied by the bitter debates, extending well into May, 1942, between the Combined Fleet, the Naval General Staff, and the Army General Staff. There was little agreement on future objectives, and literally no discussion of what, if anything, might induce the US to negotiate. There was only a sense of confused desperation and the feeling that time was rapidly running out for Japanese options.

The Midway Operation was Yamamoto's brainchild and his primary concern was clearly the destruction of the US carrier fleet. The Naval General Staff opposed the capture of Midway for several very sound military reasons, but lost the debate when Yamamoto (again) petuantly threatened to resign unless the operation was approved. The Japanese Army staff was led to believe that the ultimate objective of the Midway operation was the capture of Hawaii, and agreed to detail three Army divisions for such an objective. These three divisions may, or may not, have received orders to begin training, but by the summer of 1942, three divisions would not have been sufficient to capture Oahu, and, in any case, Japan did not possess the capability to lift or support three divisions at some 4,000 miles distance from Tokyo.

There are just a couple of problems with your suppositions.

First, the Japanese didn't have anywhere near a million tons of spare shipping just sitting around waiting for something to happen, regardless of your claim to the contrary. Second an invasion of the Oahu would require the support of the major part of the Japanese Navy, which also was tasked with covering the Malaya operation, the Philippines operation and various other minor points such as Guam and Wake.. Yeah, I know, you plan on ignoring the Philippines, Guam, etc. but exactly what does that buy you in terms of spare naval units?

But the major problems don't really start with logistics although that issue was patently impossible for the Japanese to overcome; the real problems are the defenses of Oahu. You've said that the only way a Japanese invasion of Hawaii can succeed is if the invasion force achieves complete tactical surprise; therein lies the insurmountable problem.

It is axiomatic in warfare that, when attacking a single objective, tactical surprise can only be achieved once.

Yet, in order to successfully invade Oahu, the Japanese had to do three things there, all of which were dependent on tactical surprise for their success and two of the three could not be done simultaneously.

1. They had to destroy completely the American naval force at Pearl Harbor and in the surrounding waters. If they weren't able to do that, any attempt at a landing is purely academic.

2. They had to destroy the American air power based on Oahu. It is a proven axiom that without air supremacy, no assault landing can prevail

3. They had to effect an assault landing against ground defenses as formidable as anywhere in the world.

The real problem is that all three of these conditions can only be brought about by the Japanese through attacks enjoying tactical surprise, but while the first two conditions might be achieved with one series of air attacks during daylight hours, as historically almost happened at Pearl Harbor, an assault landing cannot succeed at tactical surprise unless it is launched during hours of darkness. You can't have tactical surprise by both the landing forces and the carrier air forces; one or the other has to come first, which will deny the necessary condition to subsequent attacks.

In any case, assault landings rarely are able to achieve tactical surprise; a seaborne invasion force is just too difficult to conceal on approach and requires too much time to prepare the landing force once it is positioned off the target beaches. For example, The Japanese carrier force attacking Pearl Harbor remained undetected at 200 miles distance from Pearl Harbor, largely because it could run into it's launch position at 25 knots or better from over 500 miles out. An invasion convoy proceeding at a maximum of around 10 knots does not have any such luxury. In order to be able to launch it's attack it has to be within 4-5 miles of the beach and has to be there, not a few minutes before it launches the attack, but at least two to three hours beforehand. That means it has to start it's run in from under 100 miles. In an area with as much routine air and sea traffic as Pearl Harbor the odds of being spotted at that distance are overwhelming.

I can guarantee that neither the IJA, nor any other Army with any amphibious experience is going to allow their slow and vulnerable transports, packed to the gills with troops and valuable equipment, to steam within 100 miles of enemy air bases as existed on Oahu, nor for that matter an intact enemy naval base. They are going to insist that those bases be destroyed, or at least neutralized, by air or naval attack long before their precious transports come anywhere near the target. Of course, if that happens, there goes your tactical surprise.

Creating the absolute minimum conditions for a successful assault landing precludes the one other minimum condition for the success of that landing; tactical surprise.

There are other objections to the feasibility of a successful Japanese invasion of Oahu on December 7th., but I'll let you figure this one out before I dump them on you.

I agree with most of your statements, particularly the comment about Singapore Malaya. The Japanese were able to capture Singapore only because they had naval and air superiority. without the naval and air units that would have to be committed to the Oahu invasion, the Japanese can't take Singapore and if they can't capture Singapore, the NEI probably won't fall either. So they end up with Oahu and no oil; real smart.

I also agree that Oahu isn't going to become any bargaining chip; if the Japanese get real lucky an capture it it just makes the US public even more anxious over Japanese intentions and puts pressure on Washington NOT to negotiate. Yamamoto was extremely stupid to attack Pearl Harbor as he did, but this idea is even dumber if that is possible.

Good discussion all around, gentlemen.

__________________
Best Regards,
JW

This BS doesn't hold up to any close scrutiny. The Japanese seldom made landings against defended beaches, and when they did they invariably got into trouble. The initial Malaya landings were against a beach defended by a half-trained Indian brigade armed with rifles and a few machine guns, yet they came within a hair of being repulsed. They succeeded only when the British commanders lost their nerve and ordered a retreat. The landings against the beaches on the Bataan peninsula were all annihilated to the last man, The landings against Corregidor were badly botched and proved extremely costly, they succeeded only because the defenders were badly demoralized by their situation. The initial landings on Wake were repulsed with heavy losses.

The Japanese may have been good at making assault landings against Chinese peasant conscripts, but when they had to face defenses like those on Oahu, they were in deep trouble. In the first six months of the war, with few exceptions, the Japanese were successful largely because they were, in effect, expanding into a military vacume.

Yeah? Well, how do you explain the fact that every time the Japanese came up against the US Marines on anything like an equal basis in 1942, they lost?

What the Japanese had going for them was years of intelligence that told them where to attack so that they wouldn't meet heavy opposition. When they had to improvise after their "First Phase" operations ended, they were pathetic.

formerjughead, you replied with,

I'll give you one thing; you are certainly well thought.

Many thanks for the kind word. I do try but certainly don't always get it right.

The one thing you are missing is that Japan attacked Pearl Harbor to sink the Aircraft carriers. The American Carriers are key to Japan holding any real estate in the Pacific.

I agree completely but the presence of the American Pacific Fleet carriers at Pearl Harbor is something that not even Yamamoto could control.

I have tried to write an ATL Japanese invasion operation scenario as much as is possible, in the Japanese "style" of the day, including all of the absurd complexities and reliance on the Bushido spirit that the 1941 Japanese military was so fond of. 'Tis often not the most sensible military plannning that might have been used instead but then my ATL scenario would be an American one, not a Japanese one, wouldn't it ?

The presence of the radio capable Tatuta Maru with my ATL Japanese invasion taskforce MIGHT give Yamamoto the ability to delay the Oahu strike by one day, so as to still gain some advantage from Oahu's too deep weekend relaxation BUT that does not seem possible in the case of the near simultaneous Kota Bharu etc. landing in Malaya and Thailand.

As soon as the Japanese even looked like they would try to occupy Hawaii, for even a short period, every US Naval resource would have been allocated to the defense of the Islands.

Also quite true which is exactly why both the OTL Japanese air attack plans and my own ATL invasin plans demand complete pre-war secrecy.

Sadly for the Dec.7'41 Americans, there wasn't much else of US military significance anywhere near the Hawaiian Islands that could have rushed in to help. Had the 2 widely seperated USN carriers attacked the KB at 1:6 odds each, both would have been quickly sent to Davey Jones's Locker.

The likelyhood of US reinforcement from the West Coast is yet another reason for my ATL Japanese invaders to get ashore on Oahu fast, rather than taking other of the Hawaiian Islands and building airfields there with which to soften up Oahu for later invasion. I feel that it needed to be done quickly, or not at all.

I have typed many times that a USN Atlantic Fleet counter-attack would be expected round about the end of January 1942.

You propose that Japan occupies Hawaii for a short time ans uses it as a bargaining chip..........wouldn't happen.

Any other ATL Japanese strategy that I can think of would eventually be suicidal. But pehaps you refer instead to the low likelyhood of the even more wounded American nation ever agreeing to "play ball" ?

Guam, Midway and Luzon would not wither on the vine they would be supplied through the Phillipines, Singapore and Australia. Japan could not hold Singapore without controlling the Phillipines.

If you would re-read my posts you will be reminded that I will more quickly invade Mindanao and by establishing Japanese LBA bomber and fighter units there in co-operation with the OTL LBA units on Formosa, establish an air blockade of the Philippines as the OTL Japanese operations continue southward.

All else "withers on the vine" since, as you yourself have just stated above, EVERYTHING American available anywhere will be sent instead to the relief of a Hawaii under invasion. Not to the Philippines nor Guam nor Wake etc.

You can't have it both ways, afterall.

While I had this massive response, it seems the system has eaten it. I will add that the following tidbits:

The IJN did not practice using floatplanes from their ships for gunnery spotting either against shore targets or at sea. These were intended for scouting. So, the battleships are firing off a map as they did at Guadalcanal. Gunfire support of naval landings was not something the IJN made a habit of practicing. So, the likehood is that their efforts in this area would be like they were elsewhere:
They would fire far too few shells to be effective.
They would largely leave the target(s) undestroyed.
They would grossly exaggerate the effect they had.
The result would be the landing troops would be hosed by the defenses.

As for the coast defenses:

You forgot the two 14" guns at Fort DeRussy, along with the 20 fixed and 12 rail mobile 12" mortars that were specifically sighted for repulsing landings. These in the Philippines proved devastating against the Japanese.
The coast defenses also have nearly 100 155mm guns and 32 240mm howitzers that can be moved to one of over 100 "Panama Mounts" around the island. The 16" batteries elevate to 50 degrees and fire to 49,000 yards. They have a 360 degree field of fire their magazines are invulnerable to return fire and anything short of a miracle direct hit on the gun is useless.
The terrain is far more a henderance to the Japanese in this scenario than the US who sited their batteries to be able to blanket the island and surrounding waters with fire. A landing anywhere on Ohau is subject to 12" mortar fire in varying amounts. This alone would be a major problem for a landing force.
There were also 8" guns and 12" mortars on railcars that could move anywhere on the island's rail system. This too would prove a problem as it gives even more mobile artillery to the US to smash an invasion.
There are also bunkers and pillboxes around the island built in the mid 30's an onward.
The US coast defense fire control system like the US Army artillery system allows any battery to be controlled from any station. There are stations on most of the major mountian tops under massive amounts of earth and concrete. These will call down ungodly amounts of fire on the landing Japanese troops. Just the mortars alone would severely disrupt any landing attempt.
I would like to see the Japanese firing off a map take out a 12" mortar battery like Battery Burkhammer on Diamond Head that is built into the side of the volcanic crater and completely masked from fire from seaward. This battery if in range (17,000 yards)would have devastated a landing with shell fire.

Devilsadvocate, you waded in with,

There are just a couple of problems with your suppositions.

Only a couple ? I'm getting off lightly then.

First, the Japanese didn't have anywhere near a million tons of spare shipping just sitting around waiting for something to happen, regardless of your claim to the contrary.

1,687,000 tons actually as per the breakdown that folllows below:

Postponed invasions:

Luzon: 111 transports for 619,161 tons
Guam: 8 transports for 36,969 tons
Wake: 2 transports for 17,934 tons
Gilberts: 4 transports for 31,029 tons

Total freed shipping: 125 ships for 705,093 tons.

Added to this total is the cancellation of Japan's Armed Merchant Cruiser Program, plus the employment of the following stranded German merchantmen

Scharnhorst of (18,184 tons).
Teizui Maru 8,428 brt (taken over by Japanese on Nov. 2nd 1942)
Havenstein (7,973 tons) sold to Japan 1942 as Teisho Maru
Quito (1.230 tons) sold later to Japan as Teifuku Maru
RC Rickmers (5,198 tons) sold later as Teishu Maru
Winnetou (5,113 tons) sold later as Teikon Maru


Total additional tonnage:

72,414 (cancelled auxiliary cruiser program)
46,126 (purchases of stranded German vessels)
Total: 118,540 tons

A few more ships are available from naval programs, if necessary:

Hospital ships (4) - for 33,491 tons
Submarine tenders: Rio de Janeiro of 9,627 tons and Nagoya of 6,071 tons were being employed as sub tenders at bases the Home Islands. Being in home ports, other arrangements could have been made at these locations without impairing combat efficiency.

After this, the last major source of transports for Hawaii was either China or the civilian pool of 2.66 million tons. But China had already been thinned out, and tapping the civilian fleet would have repercussions on the Japanese economy,

"The Cabinet Planning Board calculated before the war that the civilian economy required 3 million tons of merchant shipping to continue to functioning. Coal, transportation would occupy 1.8 million tons, while the movement of agricultural products and supplies (450,000 tons) and steelmaking materials (300,000 tons) would absorb most of the rest. Any drop below the 3 million ton minimum would threaten serious disruption of the economy. Government studies predicted that if Japanese industry could call on only 2.5 million tons, the availability of resources considered to be of secondary importance (coal, salt, fertilizers, soybeans, bricks, cotton and various ores) would fall by one-fifth, and many other items would become even scarcer. A further loss to 1,500,000 tons would mean a 20 percent curtailment of steel and rice production, a 60-percent drop in the second(ary) items, and a virtual cessation of most other imports."

The Japanese Merchant Fleet in World War II, 34-35

"Later studies predicted that the planned requisitioning (2.5 million tons) would mean a one-quarter drop in steel production and about a 15-percent fall-for other products. A month before Pearl Harbor, the Cabinet Planning Board confirmed these figures, but the board believed employment of sailing ships with auxiliary engines, greater utilization of iron foundries serviced by railroads, consumption of stockpiles, and collection of more scrap iron could compensate for lost shipping."

Ibid, pp76


In the event, the total military mobilization exceeded the 2.5 million tons envisioned by a considerable margin and the 2.66 million tons remaining under civilian control was short of the 3 million tons Japanese planners thought necessary to maintain the economy at an acceptable standard. In fact, of the 2.66 million tons left to civil sector, a full 1/3rd - 840,000 tons - were passenger vessels "ill-suited" for cargo transportation and therefore of little to no use in supplying raw materials. Studies suggest that the actual tonnage of useful vessels in the civilian pool was less these passenger ships - the real pool was about 1.6 million tons (as per USSBS, Vol 9). The rest (840,000 tons) were of next to no utility (Japanese Merchant Fleet, pp75).

These passenger ships are therefore available to the military as troop transports, useful for a Hawaii invasion.

Summary:

Grand total of shipping freed up from cancelled invasions: 705,093
Plus cancellation of aux. cruiser program: 72,414
Plus purchase of German ships: 46,126
Total: 823,633 tons
Plus 2 sub tenders and only 1 (of 4) hospital ship: about 24,000 tons.
Totals 847,633 tons

Plus civilian pool passenger ships of little use to economy available as troopships: 840,000 tons.

Total potential shipping available for my ATL Hawaii offensive: 847,000 tons + an additional 840,000 tons of passenger liners = 1,687,000 tons

Second an invasion of the Oahu would require the support of the major part of the Japanese Navy, which also was tasked with covering the Malaya operation, the Philippines operation and various other minor points such as Guam and Wake.. Yeah, I know, you plan on ignoring the Philippines, Guam, etc. but exactly what does that buy you in terms of spare naval units?


Summary of Dec.7'41 OTL vs. ATL allocation of major IJN units.

Carriers
Type.......Location..........Historical.........AT L
CV..........Hawaii..................6............. ...6
CVL........Johnston...............0............... .1
CVL........Oahu (CF-CAP).......0................1
CVL........Mindanao..............1................ .1
CVL........Japan...................2.............. ...0
Total.................................9........... ......9

Seaplane Tender...............Hist...............ATL
Japan................................1............ ......1
Malaya..............................4............. .....3
Philippines..........................3............ ......3
Guam................................1............. .....0
Gilberts..............................1........... .......0
French Frigate Shoals...........0..................2
Johnston............................0............. .....1
Total................................10........... .....10

Battleships

Area.................................Hist......... .......ATL
Japan.................................7........... .........0
Malaya...............................2............ ........2
Hawaii................................2........... .........9
Total.................................11.......... ........11

(includes Yamato serving in a limited combat capacity at Oahu, OTL commissioned Dec 15th, 1941),

I assume that her construction had been accelerated early in 1941 when the imminence of war in the Pacific became apparent....the accelerated construction resulted in no problems or operational difficulties. Her trials in October 1941 were a great success, and a speed of 27.4 knots was realized....
Battleships, Garzke, pp54)

Heavy Cruisers.

Area...................................Hist....... ........ATL
Malaya.................................7.......... .........7
Hawaii..................................2......... ..........5
Marshalls...............................0......... ..........1
Johnston...............................0.......... .........1
French Frigate Shoals..............0...................1
Philippines.............................5......... ...........3
Guam...................................4.......... ..........0
Total...................................18........ ..........18

Light Cruisers.

Area..................................Hist........ ..........ATL
China...................................1......... ............1
Hawaii..................................1......... ............5
Johnston...............................0.......... ..........1
French Frigate Shoals..............0....................1
Japan...................................4......... ...........3
Marshalls...............................1......... ...........1
Malaya..................................4......... ...........4
Philippines..............................5........ ............3
Wake....................................3......... ...........0
Total...................................19........ ...........19

Destroyers.

Area.............Hist.....................ATL
China.............3.........................3
Guam.............4.........................0
Hawaii............9........................27
Japan...........25........................13
Midway..........2..........................0
Philippines.....30........................20
Air Rescue......3..........................0
Malaya.........24.........................24
Borneo...........5..........................5
Marshall.........8...........................2
Johnston........0.........................10
FFS...............0..........................3
48th/16th.......0..........................6
Total............113.....................113

But the major problems don't really start with logistics although that issue was patently impossible for the Japanese to overcome;

I don't agree, as I believe that my data above clearly shows.

the real problems are the defenses of Oahu. You've said that the only way a Japanese invasion of Hawaii can succeed is if the invasion force achieves complete tactical surprise; therein lies the insurmountable problem.

Maybe but I have done my homework and I don't think so.

It is axiomatic in warfare that, when attacking a single objective, tactical surprise can only be achieved once.

Then it had better be a good one, hadn't it ?

Yet, in order to successfully invade Oahu, the Japanese had to do three things there, all of which were dependent on tactical surprise for their success and two of the three could not be done simultaneously.

In your opinion.

1. They had to destroy completely the American naval force at Pearl Harbor and in the surrounding waters. If they weren't able to do that, any attempt at a landing is purely academic.

One of the reasons that I have sent 8 (and possibly 9 if posters here can agree on an early Yamato appearance) of the Combined Fleet's 10 battleships along to help out the Kido Butai. You haven't forgotten about the 28 (+5 minisubs) OTL Japanese submarines surrounding Oahu have you ?

2. They had to destroy the American air power based on Oahu. It is a proven axiom that without air supremacy, no assault landing can prevail.

Considering that my CF battleships will add to the destruction wrought by 3 waves (not just the OTL 2 waves) of the Kido Butai's warplanes, I don't think this too difficult. IJA landing troops will also be assaulting the coastal Bellows Field and Kaneohe NAS just after dawn also , thus freeing up additional KB flights for other strike missions against American air power on Oahu.

3. They had to effect an assault landing against ground defenses as formidable as anywhere in the world.

Except that at dawn on the OTL morning of Dec.7'41, the US Army's two Divisions on Oahu, save for a few anti-sabotage sentries ordered out by General Short, were still tucked into their Schofield Barracks and Fort Shafter beds, well within the totally unexpected reach of ATL bombarding IJN battleship guns.

None at all were even deployed, let alone dug-in, at their assigned invasion beaches. Historically the first US Army battalion left Schofield Barracks for it's assigned beach at 0930 when the OTL Japanese air attacks had begun at 0755. Nearly 1.5 hours later while NOT under IJN battleship bombardment as they would be under in my ATL scenario

The real problem is that all three of these conditions can only be brought about by the Japanese through attacks enjoying tactical surprise, but while the first two conditions might be achieved with one series of air attacks during daylight hours, as historically almost happened at Pearl Harbor, an assault landing cannot succeed at tactical surprise unless it is launched during hours of darkness.

Which is why my ATL Japanese will first land at night. Seems obvious.

You can't have tactical surprise by both the landing forces and the carrier air forces; one or the other has to come first, which will deny the necessary condition to subsequent attacks.

I don't see the situation in that way at all.

Prange's book "ADWS" details that Genda had originally scheduled his air attacks for take-off in total darkness with a just after dawn arrival over Pearl Harbor to allow daylight attacks on the USN's warships found there.

This was delayed to a sunrise take-off time when it was realized that not all of the 5th Carrier Division's (the new Shokaku and Zuikaku) pilots were night flight certified. They had been trained in night operations but rigid KB training schedules for the OTL air strikes had prevented their actual certification testing. By the simple choise of reshuffling the warplanes of the 1st and 2nd waves, this delay could have been avoided and more daylight hours thus provided to allow a 3rd wave later in the day on Dec.7'41.

Yes, such a earlier air attack might have been detected earlier by the Opana Point US radar but since the OTL Japanese didn't know of it's capabilities, I cannot now allow my ATL Japanese to attempt to circumvent it.

I can only point out that in the OTL, that radar did pick up the inbound Japanese air strike and nothing effective was done to warn PH or the rest of Oahu. I also point out that the two Japanese cruiser scout planes dispatched by Nagumo were both picked up by 3 seperate American radars and once again, nothing was done to warn either PH or the rest of Oahu.

Even if an air attack warning were issued, kost American fighters on Oahu were parked wingtip-to-wingtip without fuel nor ammunition. None would have been able to get off of the ground before the 1st ATL Japanese airstrike wave arrived.

Thus in my ATL, the 1st wave of KB warplanes will be attacking Pearl Harbor at about 0615 rather than at the 0755 time of the OTL.

with the proper co-ordination, all three ATL Japanese attack types will thus be able to "arrive" at around 0615.
The IJN battleships off Oahu's eastern shore will open fire at 0615,
The 1st KB wave will begin to bomb at 0615.
The IJA and JSNLF troops that snuck ashore in the darkness will emerge from cover and begin to overrun their assigned targets, also at 0615.

Only a very few Japanese attacks will begin before 0615, most notably an 0600 covert attempt on the Mutual Telephone Company's downtown Honolulu switchboard office.

In any case, assault landings rarely are able to achieve tactical surprise; a seaborne invasion force is just too difficult to conceal on approach and requires too much time to prepare the landing force once it is positioned off the target beaches.

With the initial landing wave of IJA light infantry troops already loaded into their lifeboat davit mounted landing barges, I don't think so.

For example, The Japanese carrier force attacking Pearl Harbor remained undetected at 200 miles distance from Pearl Harbor, largely because it could run into it's launch position at 25 knots or better from over 500 miles out. An invasion convoy proceeding at a maximum of around 10 knots does not have any such luxury.

It appears to me like you haven't yet read that my 1LW will consist of only 3 cargo-liners and just 6 JSNLF "patrol boats" already converted with diahautsu landing barges and stern ramps from which to quickly launch them into the sea. All capable of 20+ knots, not just 10.

In order to be able to launch it's attack it has to be within 4-5 miles of the beach and has to be there, not a few minutes before it launches the attack, but at least two to three hours beforehand. That means it has to start it's run in from under 100 miles. In an area with as much routine air and sea traffic as Pearl Harbor the odds of being spotted at that distance are overwhelming.

Perhaps we can have a more fruitfull discussion AFTER you have read my previous invasion postings here for the first time ?

I can guarantee that neither the IJA, nor any other Army with any amphibious experience is going to allow their slow and vulnerable transports, packed to the gills with troops and valuable equipment, to steam within 100 miles of enemy air bases as existed on Oahu, nor for that matter an intact enemy naval base. They are going to insist that those bases be destroyed, or at least neutralized, by air or naval attack long before their precious transports come anywhere near the target. Of course, if that happens, there goes your tactical surprise.

Desperate times call for desperate measures.

Again, I might find your criticisms more valid if you had actually read any of my previous postings here. You are not even remotely discussing the ATL Japanese landing plans that I have presented.

Creating the absolute minimum conditions for a successful assault landing precludes the one other minimum condition for the success of that landing; tactical surprise.

I have been quite clear that my ATL Japanese will NOT be making any assault landings at all, if, by the term "assault landings" you refer to landings on defended Oahu beaches. My vision of the initial night time landings on Oahu's shores is one of barge loads of Japanese quietly coming ashore on deserted peacetime beaches often backed by the electric lighting of the still sleeping Hawaiians.

Since Genaral Short had issued ONLY anti-sabotage alert watch orders for important installations on Oahu, there were NO extensive beach patrols nor oceanfront sentries watching for landing barges out on the dark ocean, on that last peacetime liberty Saturday night. The only "beach patrol" on that Saturday night was a once every 4 hours truck mounted drive around Oahu's coastal highway. At night, the truck headlights could be seen approaching from miles away thus giving my Japanese landing troops ample time to hide from American sight.

Even the CAC observers who were usually posted to the 100+ ridgeline observation bunkers on Oahu had been given their usual weekend off. So sure was General Short that Admiral Kimmel's (actually non-existant) long ranged PBY patrols would provide him with adequite warning, that he sent home the very men that were supposed to be watching from above to defend Oahu from seabourne invasion.

Can you imagine the telephone calls made to the Oahu police just befor sunrise ? "Yes sir, and how many Saturday night beers DID you have before you saw the entire Japanese Fleet sailing by just off of the end of your boat dock ?"
"Sure sir, we'll be right over to check it out, sir."
"Yes indeed, right away sir". Click.

My ATL Japanese landing troops would carry a few silenced pistols within the lead elements of each landing party, with one or two English speaking troopers being in American uniforms so that any accidental encounters with real Oahu Americans might be resolved quickly, and quietly.

Once ashore most would be ordered to find cover while using their night infiiltration training to carefully move into their assigned dawn attack positions.

Two groups however would be met by Japanese agents from the Honolulu Consulate, driving closed box trucks rented privately for the weekend.

One group of JSNLF troops (with a few demolition trained combat engineers assigned) from Oahu's western shoreline would be thus driven some three miles thru the pre-dawn darkness to the edge of Fort Barrette which was the home of 2x16" American CAC guns watched over by only a few anti-sabotage sentries. The American guncrews were actually billeted some 12 miles away and were themselves trucked to man that battery after breakfast each morning. Today would be much different.

Another JSNLF group landing on the Kaneohe Plains would also be met and similarly trucked 1,800' up Highway #61 to the summit of the Pali Pass, the ONLY over the Koolau Mountains road connection between Kaneohe Bay and the still slumbering City of Honolulu at that time. Once there the JSNLF troopers would deploy in highway ambush positions, set up their heavy radio (and it's generator, fuel supply and batteries) and dispatch small patrols into the darkness, both north and south along the Koolau ridgeline. Once those reached the first weekend unmanned CAC observation bunkers, the buried 25 pair telephone cable that connected all of the CAC's observers with their coastal defense guns, deployed far below, would be quickly cut. All done well before the 0606 surise.

There are other objections to the feasibility of a successful Japanese invasion of Oahu on December 7th., but I'll let you figure this one out before I dump them on you.

Perhaps you might actually read my ATL plans before wasting any more time ?

Devilsadvocate responded with more,

This BS doesn't hold up to any close scrutiny. The Japanese seldom made landings against defended beaches,

Which is exactly why I specified undefended beaches.

and when they did they invariably got into trouble. The initial Malaya landings were against a beach defended by a half-trained Indian brigade armed with rifles and a few machine guns, yet they came within a hair of being repulsed. They succeeded only when the British commanders lost their nerve and ordered a retreat. The landings against the beaches on the Bataan peninsula were all annihilated to the last man, The landings against Corregidor were badly botched and proved extremely costly, they succeeded only because the defenders were badly demoralized by their situation.

Yet, they still won didn't they. There is always back and forth in almost every battle. Such is war. But the winner is the one who quits, last

The initial landings on Wake were repulsed with heavy losses.

There were no initial landing attempts even made during the Wake Island #1 fighting. The Japanese warships were driven off by coastal defense gunfire and some good bomb hits well before any Japanese troops even tried to board their landing barges.

The Japanese may have been good at making assault landings against Chinese peasant conscripts, but when they had to face defenses like those on Oahu, they were in deep trouble. In the first six months of the war, with few exceptions, the Japanese were successful largely because they were, in effect, expanding into a military vacume.

Smart of them wasn't it.

Yeah? Well, how do you explain the fact that every time the Japanese came up against the US Marines on anything like an equal basis in 1942, they lost?

AFAIK there weren't any equal basis battles against the Marines in 1942. The Japanee were almost always low on food, ammo, air support and radio sets. And of course, we all know that the US Marines were supermen too,

What the Japanese had going for them was years of intelligence that told them where to attack so that they wouldn't meet heavy opposition.

Exactly the ATL sceanrio that I have tried to design for an Oahu invasion

When they had to improvise after their "First Phase" operations ended, they were pathetic.

What better reason for the Japanese Empire to aim for a short war against the Americans, as I have been saying all along ?

Dabrob, I think you will fit in just right here

__________________
WHEN YOU GO HOME, TELL THEM OF US AND SAY, FOR YOUR TOMORROW,WE GAVE OUR TODAY. Epitaph on the Kohima memorial .

Your plan is "Island Hopping" in reverse.

So what beaches would the Japanese land on?

If the Marines at Wake repulsed an IJN landing force why wouldn't the Oahu defenders be able to do the same thing?

The Japanese were beaten at Midway and almost beaten at Wake why would you expect them to be any more successful attacking a larger target?

I think the Japanese knew that invading Hawaii would have been too costly and a "raid" on Pearl Harbor was the most effective way to accomplish neutralizing the American fleet.

__________________
"Logos, Philos, Arete"

T. A. Gardner typed,

While I had this massive response, it seems the system has eaten it.

The same thing just hapened to me. Damn.

The IJN did not practice using floatplanes from their ships for gunnery spotting either against shore targets or at sea. These were intended for scouting. So, the battleships are firing off a map as they did at Guadalcanal. Gunfire support of naval landings was not something the IJN made a habit of practicing. So, the likehood is that their efforts in this area would be like they were elsewhere:
They would fire far too few shells to be effective.
They would largely leave the target(s) undestroyed.
They would grossly exaggerate the effect they had.
The result would be the landing troops would be hosed by the defenses.

If you were to read on and around page #260 of the 1997 Peattie & Evans book titled "Kaigun: Strategy, Tactica and Technology in the IMPERIAL JAPANESE NAVY 1887 - 1941" you would find that you are completely mistaken in your just expressed PoV. At that time the IJN was probably the best in the world at very long ranged, aircraft adjusted, indirect, heavy calibre naval gunfire. Their "Decisive Battle" plan had depended on it for decades to help in bridging the gap in battleship numbers imposed by the Washington Naval Treaty.

As for the coast defenses:

I think that you'll much prefer my listing instead:

Weapons on hand, Oahu, Dec 6th (PHA Vol 23, 2017) with corrections

Type...................Authorized..............On hand
16" ..BA.......................4...................... ....4
14".DC.........................2.................. ........2
12" DC.........................0...................... ....2
12" BA.........................2...................... ....2
12" Mortar....................0....................... ..20
8" fixed........................2.................... ......2
8" rail..........................12.................. ......12
6" DC..........................2..................... ......4
3" Coast, fixed.............0............................4
155mm.gun.................24...................... ...36
240mm..how................0....................... ...12
155mm...how..............24....................... ..24
20mmAA.....................12..................... .....0
3" AA(fixed)................26....................... ..26
3" AA(mobile).............60......................... .60
75mm M1897 ............16...........................16
75mm M1917.............72...........................64
37mmAA...................74....................... ....20
37mmAT..................160....................... ...18
37mm M1916 INF........0............................54
81mm Mor................68............................6 8
3" trench Mor.............0............................32
60mm Mor................150.........................150
Cal 50 AA................166..........................107
Cal 50 MG................185...........................12
Cal 50 MG................52.............................. 0
Cal 50 MG.................17...........................17
Cal 45 SMG.............524............................21
Cal 30 MG...............375.........................1504 **
Browning Auto.........1929........................2448

Some smaller items are still missing such as the US Army's 4.2" chemical mortars not yet listed.

However, to get an idea of the real state of Oahu's defences back then,
two more columns need to be added, the number of guns that actually had trained crews available to fire them AND which guns were actually deployed in their firing positions on the morning of Dec.7'41.

For instance, of the 36 + 24 = 50 x 155mm on Oahu that morning there were only guncrews for 24 at any one time. And on that peacetime Sunday morning NONE at all were field deployed out on their circular concrete "panama mounts". Not a single blessed one since it was the weekend and live artillery was NOT left lying around unattended in the field where it might be sabotaged.

The 37mm AA guns are another example. 20 had arrived on Oahu but by Dec.7'41 none of their ammo had arrived and no Americans were yet trained in their use.

Of the old 3" AA guns, 26 were indeed permanently installed (in groups of 4 usually or 2 sometimes) in firing positions inside of US Army bases on Oahu but each only had one (1) locked ammunition box of 16 rounds at the gun. The rest of their ammoo was locked up in the Aliamanu Crater Ammunition Depot as per General Short's anti-sabotage orders.

NONE of the 60 mobile 3" AA guns were field deployed on that dreadful morning since Kimmel had not warned Short that an enemy was near to Hawaii.

It goes on and on and on ... the deeper you dig, the more crap that you find.

Much like an apple which can look good on the outside while still being rotten to the core.

Which brings me to the 12" mortar issue. My readings indicate that the American 12" seacoast mortars exclusively fired high trajectory AP rounds intended to pierce the thinner topdeck armor of any attacking warships.

On Corregidor at least, those AP rounds, when fired at Japanese ground troops, simply punched deep into the soil before exploding and did VERY LITTLE damage at all, as a result. Why then do you repeatedly insist that Oahu's seacoast mortars would do great damage to my ATL Japanese invasion troops ?

I'll provide an Oahu battery listing next week as I am now late for a heavy date with a fishing rod, several trout and some cold beer ...

Whats the betting someone may just have seen em coming at some stage....Its one thing to launch a surprise attack from the air...Its another to sneak in a massive amphibious landing and hope it works...Yes in Malaya round back of Singapore..and others...but I think Jugheads former comrades of years gone by, may just have said hold on a doggone darned minute....

Thanks but alas I fear, not.

I am a "one trick pony" knowing much about Oahu, some about the Pacific/China War and not much else about WW2.

A specialist posting to a discussion board populated by many posters who believe that they know everything ... LOL.