Invading Pearl Harbor 1941?

Invading Pearl Harbor 1941?

Now, on my Pacific War videos I quite regularly
get comments of people suggesting the Japanese should have invaded Pearl Harbor (Oahu) and/or
the Big Island (Hawaii) in the initial surprise attack on 7th December 1941. Additionally, the authors of the excellent
book Shattered Sword, also have a homepage where they also get a similar
question . Although, usually revolving about a Japanese Victory at Midway and this was
indeed a plan by the Japanese in March 1942:
“It envisaged the following timetable: Midway and some of the Aleutians would be seized
early in June, triggering a decisive battle with the U.S. Pacific Fleet. Johnston and Palymyra were to occupied in
August. The attack on the Big Island (Hawaii) would
begin in October, culminating in an assault on Oahu [where Pearl Harbor is located] in
March 1943.” Now, Parshall made a lot of strong arguments
on their homepage that this had no chance of success, even assuming a tremendous victory
of the Japanese at the Battle of Midway. He also dealt with the December 1941 scenario
mainly focused that it would never happen from a strategic side. I thus will add more on the tactical and operational
capabilities of both the Japanese and US forces at that time. The points brought forward might seem obvious
to some, yet, I think some can learn a lot about warfare and military history if we tackle
this question. Let’s start with the actual attack on Pearl
Harbor as it happened. I think some don’t really understand how
incredibly dangerous this attack was in the first place. The Japanese used their best carriers and
drove them across the whole Pacific, we are talking about the distance of almost 4000
miles here. To give you some idea how far that is, the
distance between San Francisco and Pearl Harbor is around 2300 miles and the distance between
Berlin and Moscow is 1000 miles. [EDIT IN PEARL HARBOR VIDEO]
And the Japanese were clearly aware of this: “It [Japanese Navy General Staff] pointed
out that the essential surprise element could easily be lost by chance meeting with a foreign
ship or plane; that the ships of the attack force would have to refuel at sea in the stormy
waters of the North Pacific; and that Yamamoto would be gambling the entire first-line carrier
striking force on a single operation, one which might well provide futile if the American
fleet happened to be absent from Pearl Harbor.” So why did the pulled through in the first
place, well, after 2 war games in which in one the Japanese lost actually 2 carriers,
Yamamoto resorted basically to black mail: “Although the results [of these war games]
were far from conclusive, Yamamoto continued to insist on the Pearl Harbor plan, even threating
to resign if it were not approved. In October 1941 Admiral Nagano gave his reluctant
consent.” So, we have an already extremely reluctant
general staff. The issue is for an invasion, you need two
more things, first the Imperial Japanese Army and second more ships. Now, the Japanese are well known for their
interservice rivalry, generally the Army was concerned with everything about the continent,
whereas the Navy looked at the Pacific. “It was primarily the Japanese army which
had specialized in amphibious warfare, the navy to a lesser degree.” Only after the Doolittle Raid in 1942, the
Army seriously considered the Pacific an important area:
“It [the Doolittle Raid] accomplished what neither the Combined Fleet nor the Navy General
staff had been able to do. It convinced army leaders that the Pacific
was an important theater. For the first time, the Army General Staff
paid serious attention to the Pacific in general and to Hawaii in particular.” Yet, we are not even at war yet. The invasion of Pearl Harbor would have required
at least 2 divisions, even for the very optimistic planning of the Japanese in 1942 assumed 2
divisions. And this requires the Imperial Japanese Army
assigning those, something very unlikely. But we are not finished yet, the other problem
is, you have to add a lot of ships to your fleet. This is a major issue, see the initial strike
fleet consisted of fast vessels. The issue is transport ships and assault ships
are not. Furthermore, these ships need to be protected
as well. In other words, you don’t just gamble your
first line carrier fleet, you also gamble two divisions and more ships in a strike force
that is slower and far larger, thus easier to detect. But let’s look at some data, the Japanese
Strike Fleet left historically at Tankan Bay on 26th November at 0900 and on the 6th December
at around 2100 it was about 400 miles from Pearl Harbor. Now, here is the issue, 3 days before on the
3rd December the fleet had to refuel, this was without difficulty, then again with a
larger fleet it would have taken longer and added more complication. Anyway, lets get to the point, namely that
the fleet had to increase its speed on the 3rd of December:
“With the smoother seas, the force, which had been sailing at an economical speed of
13 knots, increased its speed to 26 knots in order to reach the launch site on schedule.” Now, here is the first issue, although an
average speed of 13 knots doesn’t seem much at first. This is not the case for non-combat ships,
namely for transport ships and assault ships this was a big deal. The first landing craft carrier that was designed
as such was the Shinshū Maru, she had a max speed of about 19 knots . It would have a
capacity of around 1400 men. The issue is, her cruise speed was likely
below 13 knots, which would have increased her fuel consumption and thus reduced her
range. Additionally, see was one of the few exceptions
other Japanese transport vessels usually had a max speed of 9 to 10 knots at the time according
Parshall. More modern Japanese amphibious assault ships
like the SS-class landing ships had a max speed of around 14 knots and a range of around
3000 nautical miles, yet had a carrying capacity of only 170 men. If we assume about 2 divisions we are talking
about 30 000 to 50 000 men depending. So even with the assumption that the Japanese
had a plenty of landing ships – which they had not – they would have needed at least
20-40 landing ships that could carry around 2000 men. This would have also slowed down the whole
operation due their limited speed. Not to mention coordination and additional
escort vessels. Now difficult it was to conduct such landings
becomes probably more apparent if we consider the following:
“In fact, it would not be until early 1944, when the U.S. Marine Corps and the U.S. Navy
began perfecting their respective arts, that a naval force could reliably transport divisional
sized units across thousands of miles of ocean, park offshore an island bastion, crush its
airpower, land assault troops in the face of heavy fire, and then support the troops
ashore for weeks at a time. The Japanese never possessed any of these
essentials characteristics of amphibious power projection.” Anyway, I am not out of nails yet and you
are still watching. So, let’s change sides for a moment. For this we look at the defenses of Pearl
Harbor. In the Interwar Years the defenses were modernized
and extended several times: “The Hawaiian Department engineering section
(aided by selecting use of private engineering firms too) undertook a large variety of projects. Between 1907 and 1938, the Army had spent
about $ 150,000,000 on defenses of Oahu (twice as much as was spent on the naval base itself).” This included beach defense pillboxes, ammunition
depots within the hills, an underground command center, numerous fire control stations and
command centers for harbor defense. Additionally, the Navy also extended the defenses
too. There was also a 1940 program by the US Army,
yet I am not sure how much of the work was actually finished by December 1941, so for
now we discount that. Now, according to at least one author the
Japanese were leaders in amphibious landings. There is just a major problem, they were not. Yes, the Japanese conducted many amphibious
landings and were quite experienced, additionally, they also had developed very good landing
craft namely the Daihatsu in the late 1920s, but the devil as so often lies in the details. First, the main issue with Japanese amphibious
landings was that they were mostly conducted against undefended beach heads and during
night. Second, they stop innovating on their landing
crafts. And third, the Army was mostly focused on
fighting the Soviets: “We do know that the Japanese army continually
honed its armor, infantry, artillery, and engineer doctrine during the 1930s and that
its capstone manual, the revised Field Service Regulations (Sakusen yomurei), appeared in
September 1938. The 1938 regulations, however, were the culmination
of doctrinal thought about how to fight the Soviets, that is, continental not amphibious
warfare.” Yet, we even have far better hands-on information
about how the Japanese performed against US forces in an amphibious landing at nearly
the time-frame we are talking about December 1941. One day after the attack on Pearl Harbor the
Battle of Wake Island (1941) started and it lasted til 23rd of December. The main difference is that in this case the
landing was performed by mainly Japanese Navy forces namely the Special Naval Landing Forces
not the Imperial Japanese Army. Wake was defended by about 440 Marines, 70
sailors and more than 1000 civilian construction workers. Yet, some of those marines were pilots and
or service personnel for planes, as such: “The task of physically defending the island
against a landing fell to the 15 officers and 373 men of the 1st Defense Battalion […].” Basically, the base was not understaffed:
“Personnel shortages limited Devereaux [Commander of the Defense Battalion] to manning only
six of his twelve 3-inch antiaircraft guns and half of his heavy machine guns. All six 5- inch seacoast guns were manned,
but the Marines had a limited of conventional fire-control equipment and no radar.” Further the island or better islands were
not particularly well suited for defense and there was a lack of barbed wire, naval and
land mines. “The small size of Wake also precluded a
mobile defense. By elimination, Major Devereaux planned a
defense at the water’s edge. Compounding his shortage of gun crews was
a complete lack of infantry to conduct even local counterattacks. […] By Saturday, 6 December 1941, the 1st
Defense Battalion had its guns mounted. The Marines held simulated gun drills, but
no firing. Their first chance actually to fire the guns
would be against a Japanese landing.” Meanwhile the Japanese had support from land-based
aircraft based on the Marshall islands. In their initial attacks they lost 2 destroyers
to the coastal guns, later they landed around 1500 of their troops outside of the range
of these guns. Wake finally fell, nevertheless, the result
was quite extensive, depending on the sources the US to Japanese loss ratio ranged from
around 1 to 5.7 according to one source or even up to 1 to 8 , note that one source counted
general losses, whereas the second counted kills. Yet, here the Marines defended unsuited terrain
with a lack of material and men against a force that was at least 3 times larger in
size. Now, this brings us back to Defense at Pearl
Harbor. Now, some might argue. But the shock of the initial carrier strike
on Pearl Harbor might limit the fighting capabilities of the defenders on Pearl Harbor. And I agree, this indeed might have happened,
but there is one problem. The landing force can’t immediately attack
with the carriers. These were 275 miles off Hawaii when they
attacked. As such, when the landing ships escorted by
other ships would finally reach Pearl Harbor, the defenders would likely be well dug-in
and well prepared as well. To quote:
“By the end of the first wave, the coast artillery troops were beginning to disperse
to their assigned defense positions. The heavy guns, fire control stations, and
beach defenses were soon manned in preparation for landings that never came.” Additionally, even if we assume that the Japanese
would attack with the ridiculous high number of 50 000 men, they likely would only achieve
a numerical superiority of 2 to 1, since the garrison at that time was about 25 000 men. Even if the Japanese achieve a successful
landing, they might take control of some parts of the islands. Yet, the problem is, their supply lines were
extremely over-extended and they were lacking ships. Especially considering that at that point
in time they prepared or conducted operations against the Philippines, Thailand, Hong Kong,
Dutch East Indies, Malaya, Guam, Wake, the Gilberts, the Bismarck Islands and New Guinea
as pointed out by Parshall. So, bringing in supplies let alone further
reinforcements was out of question. The only chance would have been if the US
forces would have surrendered, but then again the Japanese would have still needed to bring
in supplies for their garrison, the civilians and the prisoners of war, for which they had
no shipping and would have to provided escorts as well, additionally also refueling during
the voyage as well. Or as Parshall put it:
“In short, the Japanese simply did not possess the amphibious and logistical wherewithal
to assault, capture, and hold the Hawaiian Islands.” And considering that the US leadership in
1942 was even so aggressive that it risked losing an aircraft carrier to drop some bombs
on the Japanese main islands, I don’t think they would have thought twice throwing everything
against Japanese convoys in the Pacific trying to reach Pearl Harbor. To summarize, a Japanese invasion of Pearl
Harbor makes look Operation Sea Lion like a walk in the park during a warm summer night
while fairies sing in the background. I hope you learned something new. Special thanks to Naval Institute Press for
sending me two complementary copies of their books that were used in this video. Also thank you to Justin for providing further
sources and Drachinifel for some details on Japanese Landing Ships. Special thanks to Michael for sending books
that helped making this video. Also, a big thank you to all my supporters
on Patreon. As always sources are linked in the description. I hope you enjoyed this episode, thank you
for watching and see you next time.

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  1. On another note, not every US ship in Pearl Harbor had been put entirely out of action, and the Enterprise wasn't even there to begin with. So besides that it would have been an extremely high risk operation, the Japanese carriers would have had expended a good portion of their ammunitions and the landing forces of the Japanese army would have had to face the guns not only of the defence batteries, but also of the heavy cruisers and the battleships that had settled on even keel. The effectiveness of naval guns in defensive scenarios are pretty well documented with for example the Soviet battleships at Leningrad, the German heavy cruisers in 1944/45 along the Baltic coast and the Allied naval artillery fire repulsing the German counterattack at Salerno.

  2. Another thing to think about would have been the attack plans. Had the Japanese taken out all of the fuel and supplies they could have before an invasion. They would just starved themselves out.

  3. I wonder if the U.S. Navy would have discovered (and admitted) to torpedo deficiencies sooner as submarines and aircraft attempted to attack a slow moving invasion fleet. When only bomb-dropping aircraft score hits on the invasion fleet, even the thick-headed Bureau of Ordinance would realize that "something is wrong with our torpedoes."

  4. I don't about capturing Pearl harbor, but if Japanese would have won battle of Midway. Then they could given Americans the room for the money.

  5. I like the parting words. I think a lot of people, my (younger) self included, overrate the abilities of planes and tanks, and planes. Its easy to see some documentaries on the terror of the Blitzkrieg (or whatever) and forget about their vulnerabilities and limitations. Sure you can bomb the harbor but invading Hawaii? and getting it all under your control? That's a tall order, even if they had ships ready.
    I love your videos, they've given me a lot of perspective on why decisions like this one were made. Namely the invisible hand of logistics throwing out plans for operations

  6. Minor detail. The US risked two carriers with the Doolittle raid, not one. USS Hornet carried the bombers, the USS Enterprise carried fighter escorts for the ships

  7. "Makes Operation Sealion look like a walk in the park during a warm summer night while the faeries sing in the background." I'll go with that 🙂

  8. so if the japanese didn't have the ships to effect an invasion of hawaii, how'd they do it to the philipines? isn't that a similar, albeit much closer to the japan, example?

  9. I always wondered what would've happened had Japan not attacked pearl harbor. Or what would've happened had Hitler not foolishly not declared war on the US following Pearl harbor? Would the US go to war over the Philippines? If yes then could Japan have been able to achieve success without invading the Philippines too? Basically could Japan have achieved their strategic aims without provoking the US?
    In the US the popular mood at the time was overwhelmingly against going to war (%75-80 against war), so I don't think anything short of a large scale attack on the US would've made the US declare war.
    Of all the theories I've heard about how the axis could've won the war the I think the best is Japan not attacking pearl harbor and/or Germany not declaring war on the US afterwards.

  10. the Germans and Japanese were fighting an old Templar war…they baited you with one bastion..while they prepared a killer blow of UN told misery…

    Pre was German Refinery systems that converted the soviet oil into usable fuels….it was the fuel from USA and Siberian reserves that saved the Soviet collapse in Dec 1941….it was also the reason for the Japanese preemptive attack to cut that supply line from Iran to the western Soviet boundaries…

    the West became so target focused on Germany..they completely missed the prize in Asia…UK beat the German army..big whoop..they lost all their Asian colonies in one swoop thanks to Japan..

    win/win ..except for UK…USA paid for it all…it had the money though and caused the whole thing when it stole the opium trade from UK back in the 1930's…

  11. 10:41 Remember, though, that since all Marines are — first and foremost riflemen — the ground crews and remaining pilots would have also defended the island and would have been taught to crew the machine guns.

  12. The Japanese lacked the transport shipping to invade British, US, and Dutch holdings in the south AND Hawaii. They would also have major difficulties supplying a Hawaiian garrison.

  13. This had been thought about by the American Novelist Harry Turtledove in his alternative history series:

  14. Is it just me or were the graphics on the slides too high to read everything (note: I am on a chromebook, not my phone or usual laptop)?

  15. People do not understand the distances. There almost is no other point. Everything is about supply lines. I could see 1,000's of Americans getting their rifles, jumping on private boats and sailing from California, lol. If Yamamoto had a chance to see your video of how the Japanese could not win, he might have changed his mind. (you are rocking that beard bro!)

  16. This isn't exactly related, but I think the Japanese had a seriously warped view of what the American public's reaction to Pearl Harbor would be. Did they look at the outcome of the Sino-Japanese Warn, the rapid fall of European democracies, the American pleasure-seeking zeitgeist (after a decade of enormous suffering) and assume the Americans to be passive, unfit for war as a people, and that an overwhelming naval victory would bring us to the negotiating table? I may be way off and not educated enough on this, I'm just speculating. Was it just deemed necessary despite the risk of America going 0-100 in a matter of hours? It's probably somewhere in between ignorance and calculated risk, as I see it.

    I know the Japanese were extremely nervous about the potential of the Philippines, but was there some other way to avoid provoking such an overwhelming reaction amongst the American public? Was taking the Phil. necessary?

  17. Alternative question: would the Japanese have been better off not attacking Pearl at all, and fighting the US Navy when they arrived instead? Considering battleships were still considered the main striking force of the Pacific Fleet by men like Admiral Kimmel, and that the US didn't full know the capabilities of the Japanese carrier force till Pearl Harbor (as far as I can tell), seems like there is the definite possibility for a disastrous US defeat in that scenario, which would probably have a more negative impact on US public opinion since they wouldn't have cared as much about the Philippines and so on.

  18. Oil.

    14:43 Ha.

    For the IJN, taking Hawaii or even Midway would have been a disaster. Of course the justification would have been the CHANCE of forcing the USA to the negotiating table. Anyone with even a basic understanding of US (or Roman) history would have seen this to be delusional.

    The Pearl Harbor attack, and the Pacific War in general, was what the IJN did because they couldn't tell the IJA that defeating the USA was impossible. And the IJA couldn't tell the IJN the reason they had to try was that they couldn't face the Soviets. It was a stupid war.

  19. There’s a couple of things missing from this topic: A) if Japan had captured Pearl Harbor effectively every US warship in the pacific had to head for San Diego or Australia to avoid running out of fuel, instantly negatively the US fleet. Secondly an invasion attack on Pearl Harbor would have consisted of Japanese Americans attacking to sea defenses while destroyers sailed right up to the docks to unload their troops, similar to how Norway was taken.

    Yes, it was very unlikely the Japanese would have won, but if they had done it the entire US fleet would have been rendered useless due to logistical distances giving japan the time to secure the islands.

  20. Sorry but why didnt you compare it to the Invasion of the Philippines or the Malayan Campaign? In both cases the Japanese landed divisional forces and managed to defeat a numerically superior opponent, again seemingly “safe” areas that couldnt be conquered.

  21. Stupid logistics. Who cares about logistics. Like some needs to supply fuel, ammo, food and fresh troops. Nonsense I say!

  22. I saw a trailer for that movie midway recently and rolled my eyes at the premise. I was told 'don't take it so seriously, it's just a movie'.
    Some family members went to see it and the first words that came out of their mouth were 'it was a real eye opener!! Did you know that Japan was about to take over the whole of America?!'
    Propaganda like that about 'murica being the poor little underdog is why their voting population are always convinced that their military budget needs to be bigger and bigger in order to ' defend themselves'. Even when their military has more funding than God and is so far away from any potential threat it might as well be on Mars.

  23. I love my girlfriend but she Insists that the Japanese military should have invaded the West Coast after Pearl Harbor. Yolo with the entire Japanese Army and land on California

  24. The better question would be, what would have happened if the Japanese made another attack against the oil reserves.
    Could the US Navy have operated as they did with their largest fuel supply in up in smoke?

  25. Pearl Harbor raid was a huge risk and it paid off because it was a fast strike on a unalerted opponent. Trying to sail a invasion fleet at speed into the Hawaii region would have been noticed even if only at 200 miles it still gives plenty of time for full alert before troopships arive or even combat ships get in range to start bombardment.

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