Japan's intentions towards Hawaii?

World War II Japanese Military
#1

I don’t know if this has been discussed before, but nothing is coming up in the early search pages.

It is generally stated that the Battle of Midway was limited to the IJN’s quest for ‘the decisive battle’ to wrest control of the Pacific from America.

However, it has been argued that Midway was part of a larger Japanese plan to capture Hawaii to exclude America from effective action in the western Pacific, in part to force America to come to terms with Japan. A summary of the research and argument is here.
http://www.users.bigpond.com/pacificwar/midway/ScopeofMidwayOp.html

If Japan had captured Hawaii, it would certainly have diminished America’s ability to project its naval power into the western Pacific, with obvious consequences for the thrust across the central Pacific towards Japan.

Hawaii combined with the Aleutians, Truk, and Rabaul would have given Japan a north-south maritime ‘Iron Curtain’ of sorts in the Pacific, which combined with Japan’s advances towards the Solomons etc would have put it in a very good position to deny or at least limit American LOC to Australia to build up a base for the SWPA attack towards Japan.

Occupying Hawaii makes a lot more sense in strategic terms than confiing Japan’s actions to a naval win against the US when American production capacity could easily replace and exceed the naval losses at Midway when Japan clearly had no ability to invade the US mainland.

The argued threat to Hawaii reinforces the inference that the battles which mattered most in turning the tide against Japan’s relentless advance in 1942 were the naval battles in the Coral Sea and at Midway, as they forced dramatic re-evaluations of Japanese strategic intentions and prevented Japan from gaining territory which could have put it in a much better position to negotiate terms with the Allies or, failing that, just hold what it had taken. Or even advance further, notably into Australia which would then have created massive problems for the Allies as America would have to cross the whole Pacific to reach Japan or a thrust would have had to come from India, which was beyond British and even Allied resources given the LOC, fuel and shipping required to get there from America as the main combatant and logistical supplier.

#2

I just read a passing reference by a mid-level WWII Japanese naval officer to occupying Hawaii.

He didn’t expand on it, but it got me wondering again whether there was some plan or intention to take Hawaii at some later stage after Pearl Harbor?

This could explain why Japan didn’t destroy the oil storages as it was desperate for oil. It also had almost no ships which could reach Hawaii without refuelling en route, so capturing oil stocks there would be a huge benefit after occupation to use it as a base for operations.

It could also explain why Japan didn’t attack the dock facilities to cripple the port and repair capacity when Japan knew its attack in shallow water wouldn’t necessarily prevent some ships from being repaired and returned to service.

Then again, doing any of that was beyond the necessary scope of the first wave attack which had to sink ships and neutralise the American air capacity, so the decision not to launch a second wave is a sufficient explanation for the failure to destroy oil storages etc.

Still, the preservation of oil and dock facilities fits equally well with the arguments in the link in my first post that Japan intended to take Hawaii, and more so as Yamamoto was the strategic planner for both Pearl Harbor and, apparently, the Hawaiian occupation. Moreover, Yamamoto is said to have requested on 9 December 1941 a plan for taking Hawaii, which could be consistent with his earlier intention to take Hawaii depending upon the success of the Pearl Harbor attack.

#3

But wouldn’t the US Army destroy the oil if an invasion was imminent? Surely Yamamoto would consider that as to be expected.

The greatest difficulty Japan would have is supporting the troops landed for any lengthy stay. That’s a awful long supply line to go from Japan to Hawaii. A supply line submarines would undoubtedly try to cut.

Consider this, even we had to wait several years to invalid Japan territory with any hope of being able to keep our gains.

Deaf

#4

Sorry, Rising Sun, but no cigar. It simply would have made infinitely more sense and been much easier to invade Hawaii as part of the attack on Pearl Harbor. That they had no marines or army units with them that could have done this was a matter of very poor planning on their part and betrays an entirely naive belief that the shock of this attack would cause the US to whimper in silence. Leaving the oil storage tanks was not premeditated tactic, but rather the consequence of not ordering the second strike which had been planned. The fact that not a single carrier was in the anchorage at the time was the result of poor intelligence and, as it happened, was fatal for the Japanese.

#5

Id go along with this. In fact I read recently that the Japanese maritime transport capability couldnt even feed the population of Hawaii let alone a proposed Japanese garrison. I suspect that the Japanese hierarchy knew this as they were not entirely stupid.

#6

The lack of merchant shipping was perhaps the primary single reason Japan lost the war.

It lacked the shipping to maintain and fully exploit its expansion in South East Asia and and the South Pacific, never mind Hawaii. This deficiency was duly compounded by Allied reductions in that shipping and further compounded by Japan’s inability to replace those losses.

This led to some desperate but ultimately inefficient measures to try to overcome that lack and those losses, notably the Burma railway which never managed to deliver more than about a third of the intended tonnage to maintain Japan in Burma and supposedly to equip it for the thrust into India. And some other hugely inefficient attempts to compensate such as using submarines, which could carry bugger all compared with a merchant ship, as supply ships to remote posts.

Separately, shipping to feed the Hawaiian population wasn’t likely to be an issue. The Japanese wouldn’t bother feeding the Hawaiians unless it was in their interests. Much more likely to use them, or at least the non-Japanese elements, as barely fed expendable slave labour as they did everywhere else they went.

Japan’s leadership mightn’t have been entirely stupid, but it went close as a result of allowing arrogance to blind it to the reality any adequately informed and reasonably dispassionate analysis would have revealed about its ability to win the war, even without the benefit of modern hindsight.

#7

Your link is broken, RS*. :smiley:

In any case, I wonder even if the Japanese brought a Naval infantry landing force, if they would have been repelled almost unquestionably. The Japanese tended to underestimate their enemies at points and the initial landing on Wake Island was a near disaster with the first Japanese landing almost wiped out to the man.

Secondly, with the US carriers being away from Pearl, this surely would have complicated any plans for a landing to begin with…

#8

Does anyone know the U.S. troop strength in Hawaii at the time of Pearl Harbor? Was there a division or regiment? How may costal batteries (14 inch, 8 inch, etc…?)

Could the U.S. have stopped say one full Japanese infantry division, 15,000 men, from landing and holding for several days? I doubt the Japanese could feed that many troops for a long period but could we have repelled them?

I also feel the Japanese, knowing they had to invade Singapore, Malaysia, the Philippines, Java, etc… not to mention China, well they were pretty stretched. So I doubt any prolong stay could have been envisioned. BUT, they could have totally destroyed all the facilities, including all those oil tanks with the Pacific Fleets oil reserves! Maybe a 1000 man commado raid.

Deaf

#9

The US had 45,000 troops in Hawaii at the time of PH. The full order of battle can be seen here http://www.usarpac.army.mil/history/dec7_hawndept.asp

BUT–these were peacetime troops–not trained men and the US was woefully poor at having trained soldiers and sailors even well into the war.

#10

The two divisions had been through a full training cycle since the mobilization in 1940. The overseas garrisons, particualry Hawaaii & Panama had priority for the best trained men & battalions. The National Guard regiments there had the bulk of the incompetent state politcal appointees weeded out. Most of the officers and NCOs had been through the school appropriate to the job they were holding. Both divisions had a high portion of Regular Army officers on their staff & command positions. While very few of the US Army soldiers had any combat experince they were not ill trained.

The US/Fillipino Army on Luzon was overall far less trained, or equipped than either the US corps on Oahu or the Brit Commonwealth army in Maylasia. Yet they were able to stall the japanese on the Battan pennensula for over four months.

#11

The problems for the Japanese planners were actually much worse than this implies. Not only were the US troops on Oahu very well trained and armed, and all the supporting arms in position, but the natural defenses were extremely formidable. During the winter months, the surf in the North Pacific closes out most of Oahu’s beaches in terms of reasonable landing conditions, The few southward-facing beaches which have possible surf conditions a few days a month (these however, are unpredictable) tend to channel any potential landings right into the teeth of the coastal defenses. A Japanese invasion force might arrive off a given beach to find itself forced to wait days for reasonable surf conditions. Meanwhile the defenders will be fully alerted, beach defenses would be manned, and the American long range artillery (155 MM guns) shelling the transports from pre-sited positions in the mountains behind the beaches.

Moreover, the Japanese would face an impossible dilemma involving American air power on Oahu. Historically, the IJN approached Oahu from the North, making a high speed run-in at night to a point about 250 miles Northeast of the island, from which point the Pearl Harbor attack was launched. That was all well and good for the purpose of launching a couple of quick air strikes. But getting a large, 10-knot invasion convoy into position a few miles off the beach is another matter entirely.

Such a convoy cannot approach closer than about 250 miles until Oahu’s air power is neutralized, but once that occurs, the island’s defenders will be alerted and manning the beach defenses. If the convoy tries to sneak in without destroying Oahu’s air power it will be destroyed. Either way, what it boils down to is that any Japanese attack cannot achieve full surprise and will have to face the full force of the defensive measures. The Japanese just did not have the overwhelming force, nor the means to transport it, necessary to give them any chance of capturing Oahu.

#12

I once read a book on Japanese intelligence, descriping how thouroughly the Japanese investigated Pearl Harbour, with a view to attacking the US fleet. There was no mentioning at all about Oahu as a whole, possible landing sites or other invasion related intelligence gathering. It could be on omnision…

Anyway, 9dec1941 is awfully late to request planning for an invasion and suggests that there was no plan.
Surprise would be essential to a succelful invasion and securing surprise coming back a second time seems impossible. An invasion plan requested on 9dec41 must have foundered on this issue alone.
That leaves an invasion launched together with the first strike on the US fleet, retaining the element of surprise. Leaving out Narvik´ing Pearl Harbour with troops riding in on destroyers and cruisers (apart from the suicidal aspect of the idea, the distance from Japan to Hawaii probably makes it impracticable), this would still be extremely unlikely.

#13

From what I have gleaned from various books and documents, this is essentially correct; prior to Pearl Harbor, Japanese intelligence had focused on the Naval Base, and larger military installations like Schofield Barracks, and knew little about Oahu itself or defense plans in case of an invasion.

On the other hand, The Japanese were often casual, to the point of stupidity about invasion planning. At Midway, aside for some submarine reconnaissance of the atoll and a few aerial pictures, the Japanese had no information whatsoever. They were unaware of the northern passage through the reef, had no idea of the tides, beach gradients, defensive positions, etc. But that didn’t stop them from “planning” an invasion. According to “Shattered Sword”, it probably would have failed.

Aside from the logistical shipping (which the Japanese didn’t have), an invasion of Oahu required two things; control of the sea around the landing beaches, and continual air superiority from the time the invasion transports came into range of Oahu’s air power, until the bulk of the troops were ashore (probably a period approaching 36 hours). Given that Pearl harbor held a very heavy concentration of surface sea power, land-based air power, and could call on naval aviation in the form of three large carriers, it’s obvious that attacks to neutralize these factors would be absolutely necessary before the invasion transports could approach the island.

However, in doing so, the element of surprise would be lost as far as the actual landing was concerned. Given that the Japanese historically planned to commit only three divisions to an Oahu invasion in the fall of 1942, it’s extremely likely that losing the element of surprise would be fatal to any hope the Japanese might have of establishing a secure beach head. Even a warning of an hour or so before the landing would give the very formidable coastal batteries sufficient time to be manned, and open fire on the transports as they came into range, not to mention the heavy 155 MM guns of the field artillery which could be deployed to pre-built firing positions in the mountains.

In my considered opinion, a successful Japanese invasion of Oahu at any time in the war, is a non-starter.

#14

Given that the Japanese historically planned to commit only three divisions to an Oahu invasion in the fall of 1942

They did plan for an invasion in the fall of 1942?
By then their only chance was to dig a tunnel from :wink:

#15

Yes, my understanding from reading Tully and Parshall’s “Shattered Sword”, is that Midway was a preliminary step in a plan to invade Oahu about three months later. The IJA planned to use three divisions, which, in my opinion, was woefully inadequate in late 1942.

And I agree, their best bet for success would probably be starting a tunnel from Tokyo as soon as possible…or maybe negotiating a license form Howard Hughes to build about 250 “Spruce Geese”…

#16

And I thought the Germans were the masters of supporting military ambition on unfounded optimism :wink:
And for natural obstacles: September 1942, how is the surf at Oahu at that time of the year?

By the way of large aircraft… in 1944 the chief of Nakajima had proposed for 400 of his Fugaku project aircraft, in a transport version, to unload 120000 troops at Seattle -Tacoma airport, to move overland to destroy the Boeing, Renton plant, and then fly home.

Needless to say no Fugaku was built in any version, but Chikuhei Nakajima certainly had big plans for this aircraft.

#17

The Japanese military always had “big Plans” and those plans often got them into “big Trouble”. The Japanese far out weighed the Germans in unsupported and unjustified military optimism. Often their plans were just nothing m ore than wishful thinking.

What were the beaches like on Oahu during the winter? Well, Oahu is in the North Pacific where the prevailing swell is north westerly. So the Northern and western beaches on Oahu are almost always closed out by high surf to any landings. Beaching a loaded landing craft becomes problematical in anything above a two foot swell. At three feet it becomes more than problematical, and at four feet, you can forget it. The Eastern beaches aren’t much better because of the orientation of the beaches and the way the swell rolls in. There are many good landing beaches on the western side anyway.

The only decent landing beaches are at the southern end of Oahu in front of Honolulu and Waikiki. These beaches are fringed by a reef, so one has to time the tides correctly to allow boats to get over the reef. Even the south side can be closed out by heavy surf, and during the winter, there are only perhaps eight to ten possible landing days per month. Of course it’s impossible to predict which days will allow landings each month unless you have a pretty good picture of the North Pacific weather cycles, since prohibitive surf might be generated by storms thousands of miles away.

Besides high surf, and the reef, the problems of landing on the southern beaches of Oahu were complicated by the fact that Americans realized that the Southern beaches were the only possible ones which could accommodate a large scale landings, and this is where they cited most of the coastal defenses; from 16" to 12" batteries, 155 MM field artillery, 75 MM anti-boat guns, and heavy AA artillery, The beaches also were strewn with barb wire entanglements and MG positions. Fort Derussy, which still sits right in the middle of Waikiki beach, mounted 14" guns and 3" AA guns. It is now a museum where you can see the shell handling arrangements for the 14" guns. A pre-landing bombardment was not possible, unless the ships were willing to risk a duel with the shore batteries. The transports would be forced to anchor far out and use their landing barges to run ijn troops and supplies, slowing any assault landing to a crawl.

An assault landing on Oahu in 1941-42 would have presented the most difficult military problems of any landing anywhere in the world at that time. The following link is for a surf height model which demonstrates why an assault landing on any of Oahu’s beaches would be difficult.

http://www.stormsurf.com/locals/hi.shtm

#18

Dang, I gotta go to Hawaii one day!

By the way of large aircraft… in 1944 the chief of Nakajima had proposed for 400 of his Fugaku project aircraft, in a transport version, to unload 120000 troops at Seattle -Tacoma airport, to move overland to destroy the Boeing, Renton plant, and then fly home.

And what were his plans to, uh, you know defend against fighters? Defend against lots and lots of fighters.

Well you can’t blame him. Hitler came up will all kinds of ideas to ‘crush’ the Allies. Italy though was smart enough to get out of the game early.

Deaf

#19

Pictures of me and my wife in front of the Fort Derussy Museum

Hawaii08B.jpg

Fort Derussy 02.jpg
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If you Google 'Fort Derussy", you can find links to nearby hotels. We stayed at the Sheraton which was less than a block away. I normally stay at the Ilikai, which is about a quarter mile away.

Man you got me on that one! I was trying to figure out how he was going to sneak in under the radar, avoid all the troops at Fort Lewis, and then take off again, while half the fighters in the Pacific Northwest were strafing the runways at the Seattle-Tacoma airfield.

Since the planes were never built we don’t have to worry about it, LOL!

#20

Your wife looks rather pleasant, but you seem somewhat rigid and hollow. :wink: :smiley: