Why did Japan attack Pearl Harbor?

[Jecito]

The obvious answer to destroy the U.S pacific fleet due to the oil embargo. Japan took the gamble that destroying the fleet would give them time to consolidate their position until the US rebuilt. A gamble that would have looked very risky with US industrial power ten times that of Japan.

But what if Japan had gambled that US isolationism would prevail as it had done with Hitler, and ignored Pearl Harbor and the Philippines, concentrating its forces on the British and Dutch East Indies, India and Australia. They would have had a much larger combat force. With this force could Japan have invaded Australia, threatened British India?

Without Pearl Harbor would Hitler have prevailed in Europe or have been defeated by the Soviet Union? Or would Hitler have won with the Soviet Union being attacked in the Pacific by Japan. Leaving Britain alone to fight Germany.

Would the US have declared war on the Axis powers without the shock attack of Pearl Harbor? If so, when? What would be the trigger? And by that time would it have been too late? One cannot underestimate the America first isolationist policy in the American public. Americans overwhelmingly supported Roosevelt when he openly declared in a campaign speech on October 30,1940: "I have said this before, but I will say it again and again and again: Your boys are not going to be sent to any foreign wars."

 

[swerve]

The USA was already intervening against Japan, & although Japan didn't know the full extent of it (e.g. the US fighters & crews being sent to help China hadn't yet encountered Japanese aircraft), the Japanese were well aware of the US embargo.

You don't orchestrate an embargo on supplies, jointly with Britain & the Dutch government in exile, to keep NEI & Malayan resources from being sold to Japan, then stand by while they are taken by Japan. Or at least, not in the thinking of the Japanese government. They (correctly) took US intervention for granted if they invaded the NEI & Malaya. What they were uncertain about was the probable scale of it, & in that they may have prompted to act by mistaken views.

 

[Beatmaster]

The obvious answer to destroy the U.S pacific fleet due to the oil embargo. Japan took the gamble that destroying the fleet would give them time to consolidate their position until the US rebuilt. A gamble that would have looked very risky with US industrial power ten times that of Japan.

But what if Japan had gambled that US isolationism would prevail as it had done with Hitler, and ignored Pearl Harbor and the Philippines, concentrating its forces on the British and Dutch East Indies, India and Australia. They would have had a much larger combat force. With this force could Japan have invaded Australia, threatened British India?

Without Pearl Harbor would Hitler have prevailed in Europe or have been defeated by the Soviet Union? Or would Hitler have won with the Soviet Union being attacked in the Pacific by Japan. Leaving Britain alone to fight Germany.

Would the US have declared war on the Axis powers without the shock attack of Pearl Harbor? If so, when? What would be the trigger? And by that time would it have been too late? One cannot underestimate the America first isolationist policy in the American public. Americans overwhelmingly supported Roosevelt when he openly declared in a campaign speech on October 30,1940: "I have said this before, but I will say it again and again and again: Your boys are not going to be sent to any foreign wars."

Your comment is not totally correct because Japan was already cut off oil so they did have left a few months of oil supply to fund there war, so attacking the US fleet in pearl harbor was almost the only option to free up mutch more oil reserves.

Eventually these feelings translated into the USA leading an international movement to isolate Japan economically and thus force them to withdraw from China. Primarily the USA plan was to cut off credit to the Japanese which would prevent them from being able to purchase petroleum. Japan received petroleum (an absolutely vital economic and military commodity, then as it is now) from three sources: The USA, Dutch east indies (Indonesia) and Burma (British controlled in the 1940's). The USA inspired movement included all three sources.

Japan could/would not accept a withdrawal from the Chinese war and instead began planning a first strike against the USA navy. Eliminating or reducing the USA naval forces in the Pacific would make the Japanese navy paramount, and thus Japan would be able to defeat the economic consequences of the USA ultimatum. After eliminating the USA navy Japan planned to occupy the Dutch East Indies and Burma, thus gaining control of enough oil to run their military and economy.

The strike on Pearl Harbor did exactly as hoped by the Japanese. The USA fleet was crippled. The Dutch lacked forces to repel the Japanese. The British navy (as ordered by Churchill) sent forces to defend their areas but these were totally inadequate for the job and were decimated quickly. Japan occupied all the oil producing areas and settled down to a war of attrition against the USA, which they hoped would wear down the USA politically and enable them to keep their conquests.

Pearl Harbor was bombed by the japanese for several reasons. 1. When the japanese decided to attack america, they knew that almost all of the immediate forces were naval. Hence, they decided to bomb pearl harbor, as it held the majority of the american naval forces in the pacific. By bombing the navy, they managed to cripple any efforts at an attack force following them immediately to retaliate. 2. Geography. They also decided to attack pearl harbor, but i believe the final decision was not made until approximately 2 to 3 days before the attack. Other targets included san francisco, large coastal cities, etcetera etcetera. They decided upon pearl harbor because it was closer to japan than the U.S., and they would have less distance to travel. The closer they came to the U.S. coast, the larger the chance of being detected, and forced to turn back. Also, if they attacked the mainland, they would have to pass hawaii on the way back, and by that time a force would be following them. 3. Deception. While the japanese navy was steaming towards hawaii, their ambassadors in D.C. were trying to convince the government that japan would not attack. Unfortunately for them, some people were getting suspicious. The fleet decided to attack then, instead of risking the longer journey to the coast. hope this answered your question.

Source for this coment: Several historical Websites


And the britain part of your comment before Japan did strike the US there was already massive support to the UK by the US with Food, Weapons, and Pilots the attack on the US only speeded up the proces to send US troops to Europa to defeat Hitler. and eventually Japan by dropping a 2 A-bombs.

And do not forget it was not the US who declared war to Hitler but Hitler ordered his U-boats to attack food convoy's and American shipping routes to cut off supply to the British forces so infact, the US was already at war with Hitler because Hitler Declares War on the United States December 11, 1941 and the attack on pearl harbor was December 8, 1941
This due the fact that Japan and Germany are ally's around this time period.
So avoiding a war by the US is totally nonsens because they are already several months unoffial at war with nazi Germany due the massive help they did give to the British forces.

anyway i hope that this gives a little view of the situation at that time.

 

[Citgab]

The Japanese made the same mistake as the Germans. Their actions were predicated on a flawed analysis that their potential adversaries would not resort to total war.

They both started their programs of territorial expansion by nibbling around the edges, taking bites so small that in their deluded perception of their potential adversaries reluctance to fight, the loses would not pass the threshhold of general warfare.

The Japanese were themselves surprised by their success at Pearl Harbor. They were realistic enough to understand that the could never defeat America because of its industrial superiority and the great distances across the eastern Pacific Ocean. The US had many potential staging points in a drive to the east but except for the Hawaiian islands the eastern Pacific is bereft of possible staging points within range of the American heartland. Japan and Germany both errroneously regarded America and Britain as paper tigers that might talk the talk but when push came to shove would not fully commit to total war and would collapse internally like France.

 

[merocaine]

I've always wondered why the Japanese didn't push there advantage after Pearl Harbor, and seek again to inflict that all important decisive defeat on the American Fleet, pretty much the fleet that they would fight at Midway and Coral sea.
In my mind I can't see why they didn't blockade or assault Pearl Harbor, and force the American fleet back to the Mainland. I don't imagine that would have changed the end result, just delayed the reckoning.

Pearl Harbor was an attempt to eliminate the carrier fleet, when it failed why didn't they follow it up?
If I was them I would have made it my mission to completely destroy the pacific fleet.

No doubt someone who knows something about naval warfare will set me to rights!

 

[Ananda]

I've always wondered why the Japanese didn't push there advantage after Pearl Harbor, and seek again to inflict that all important decisive defeat on the American Fleet, pretty much the fleet that they would fight at Midway and Coral sea.

From several publications and at one time I have read a memoir of a Japanese captain (he's the last captain of Yahagi the last japanese cruisers)..the order for the rest of the fleet (at the same time Nagumo's task force attacking Pearl Harbour) was imediately went south. Japanese did not hide their main intentions was Oil Riveneries in Dutch East Indies on Sumatra and Borneo.

They don't have much supplies to extend fight with US in pearl harbour at the same time doing South East Asia conquest. It has to be a one time deal, destryoing as much as possible of US Pacific Fleet, to reduced much of potential adversaries when they're after the rest of SEA.
That's why many Japanese historian also say that Yamamoto was a great gambler.

 

[Firn]

I think swerve has laid out the strategic situation quite well. A coordinated blockade of all ressources important to wage war and the increasing efforts to support the enemies of Japan left basically with two paths:

a) Coming to terms with the allies. This would mean a humilating retreat in which the military and political leaders of Imperial Japan would loose their face

b) A quick decisive offensive to knock out the military might of the blockading forces. This is followed by a concentrated effort to secure the ressources necessary for war. Hopefully the military might of Japan will limit the objectives of the USA and thus the war. In this case the attack would have been a huge strategic victory.

So whe you analyze the strategic position of Japan the decision to attack Pearl Harbor is not as farfechted as it seemed. To which extent Roosevelt gambled on the fact that after all the blockades Japan might feel forced to act directly against the USA is hard to know.

 

[Gremlin29]

But what if Japan had gambled that US isolationism would prevail as it had done with Hitler, and ignored Pearl Harbor and the Philippines, concentrating its forces on the British and Dutch East Indies, India and Australia. They would have had a much larger combat force. With this force could Japan have invaded Australia, threatened British India?

The attack was preemptive, I doubt the US would have stayed out and the Japanese did as well. Only problem is, the attack was a complete failure. No flat tops were harmed in the making of this attack (attempt at humor) which was the strategic target, one WW1 era battleship and 2 tin cans destroyed. Every other ship at Pearl that day that was damaged, was put back into action.

Would the US have declared war on the Axis powers without the shock attack of Pearl Harbor?

The US didn't declare war on the axis even with the shock of Pearl Harbor. Hitler declared war on the US some days after Pearl Harbor.

 

[HKSDU]

The attack was preemptive, I doubt the US would have stayed out and the Japanese did as well. Only problem is, the attack was a complete failure. No flat tops were harmed in the making of this attack (attempt at humor) which was the strategic target, one WW1 era battleship and 2 tin cans destroyed. Every other ship at Pearl that day that was damaged, was put back into action.



The US didn't declare war on the axis even with the shock of Pearl Harbor. Hitler declared war on the US some days after Pearl Harbor.

ITs not the ships that were damaged that hurt the Americans. Ships can be re-built. It was the number of Americans died during that attack. So it had a big impact.

 

[Ozzy Blizzard]

The whole pacific conflict was a geopolitical contest between two rising maritime powers, the US and Japan. The ENTIRE conflict between these two powers, the introduction of Britain and Australia into the war was incidental. The US could not have allowed Japan to achieve hegemony over the eastern Pacific basin, that's the whole reason the US employed an embargo on japan in the first place. "Isolationism" only applied to Europe because at the time it seemed that US interests were not served in the First World War and that vital US interests were not at stake in the current European contest. It would have been IMPOSSIBLE for japan to conduct a pacific war and not confront the US, if they hadn't have launched the pearl harbor attack they just would have faced an intact pacific fleet off Malaya supplied from manila, in addition to UK and Australian naval forces. Not a pretty strategic outlook.

The entire premise of this thread is faulty.

 

[Ozzy Blizzard]

I've always wondered why the Japanese didn't push there advantage after Pearl Harbor, and seek again to inflict that all important decisive defeat on the American Fleet, pretty much the fleet that they would fight at Midway and Coral sea.
In my mind I can't see why they didn't blockade or assault Pearl Harbor, and force the American fleet back to the Mainland. I don't imagine that would have changed the end result, just delayed the reckoning.

Pearl Harbor was an attempt to eliminate the carrier fleet, when it failed why didn't they follow it up?
If I was them I would have made it my mission to completely destroy the pacific fleet.

No doubt someone who knows something about naval warfare will set me to rights!

I think it was mainly because Pearl Harbor was the enabling attack, not the objective. It was by no means certain that the Japanese would be able to take Singapore and Manila, the allies still had significant naval forces and armies in place. If the Japanese kept the bulk of their navy around pearl harbor for an extended period (possibly of months) they would not have have had adequate naval forces to protect the invasion forces in the push to the dutch east indies, which would have allowed the allies a chance to reinforce and strengthen their positions in Malaya and the Philippines. Now Allied forces in Malaya and the Philippines were inadequately supported with air and naval assets, but the Japanese could not have bet their entire war planes on this. Thus if they decided to blockade pearl harbor they could not have moved south toward the oil fields of Borneo, the reason they attacked pearl harbor in the first place. They didn't want to get bogged down in an amphibious invasion of a well defended US possession thousands of kilometers away from main supply centers when it did nothing to alleviate their oil supply situation.

The Japanese didn't have much of a choice, their objective was South East Asia, and apart from disabling the US' ability to stop their drive south Pearl Harbor was not strategically vital. Its easy to view Japans actions in 1941 through the prism of 1943, but from their perspective pearl harbor itself (the base not the attack) was a sideshow, their objectives lay to the south.

 

[DTA]

aim

:japan's main aim was to shock the US as never before, destroy them mentally

 

[Gremlin29]

ITs not the ships that were damaged that hurt the Americans. Ships can be re-built. It was the number of Americans died during that attack. So it had a big impact.

US casualties were roughly 2400 killed including men, women and children and another 1800 wounded. Hardly a big impact on military manpower for the US, even for the still smallish 1941 US military.

:japan's main aim was to shock the US as never before, destroy them mentally

I have always understood that Japans goal was to eliminate meaningful US naval involvement for a short period of time while they made their final gains, consolidated and then sued for peace.

In comparison, just 6 months later the US and Japan had a little battle at Midway where Japan lost 4, count em 4, carriers and numreous other ships.

 

[wtsimpson7]

Amazing what a demand for precious resources can cause.

 

[Ozzy Blizzard]

Amazing what a demand for precious resources can cause.

It was more than demand for resources, it was demand for hegemonic control of the region because Japan could not rely on the sentiment of foreign powers as an assurance not to interfere with resource flows. Hence the need for a world class navy and hegemonic control over china and eventually South East Asia. Japan was on a collision course with the US well before the battle of Tsushima, and she was always at a significant disadvantage. Its probably a rivalry that will rear its head again in the next 50 years with a similar outcome.

 

[The_Zergling]

Its probably a rivalry that will rear its head again in the next 50 years with a similar outcome.

Wait, what? Japan against the United States?

 

[Ozzy Blizzard]

Wait, what? Japan against the United States?

Sure, think how different the world looked 50 years ago. Japan and the UK were allies in 1918, at war just 25 years later in 1943, and were de-facto allies again by 1968. The rise of china will cause Japan to come into its shell and militarize. Once it does it will likely be the major east Asian power (japan is much stronger fundamentally than China which suffers serious centrifugal forces such as crippling social and demographic problems), and will need to dominate parts of East Asia and South East Asia to secure both labor and hydrocarbon supply routs from the middle east. The US will oppose any rising power on the Eurasian land mass that could potentially threaten its global domination, especially a naval power in the pacific basin. The fundamental geographical and economic realities that lead to the pacific war in 1941 still exist today, but we are still in the artificial state of "recovery" after the Japanese defeat in 1945.

Imagine how unthinkable the cold war would have seemed to someone in 1910, the Franco-British and German alliances were the global powers of the day, the US was a neutral rising power and Russia was a second rate but stanch ally of capitalist the west. By 1950 the two dominant global powers were the US and the Soviet Union, one with an empire as close as anyone had come to complete domination of the Eurasian land mass since the Mongols and the other with total domination of the worlds oceans, the great European powers new junior partners in alliance systems (Germany split in two). Yet the fundamental geopolitical question that drove all European conflicts in the 1st half of the 20th century would have been as plain as day to someone in 1910: What place did Germany have in the European system? That question would only be resolved in 1992 after reunification and 3 world wars, 2 hot 1 cold. In the pacific the same motivations that drove the US into a confrontation with imperial japan still stand, and as Japan rises t reclaim its true place as the leading regional power the US will confront the threat to its hegemony. Truly the US will confront any threat to its hegemony, remember friendships are not eternal, only interests.

 

[Palnatoke]

I think it's important to realize that both Germany and Japan viewed themselves as being the weak. Germany knew that it was outmatched by UK, france and the USSR together with their allience partners, and Japan knew that it was outmatched by the US and USSR.

That meant that Japan and Germany were not only willing, but infact forced to accept big riscs.
As Halder put it, when he finally accepted the operational plan: "Fall Gelb" (the attack on Low countries and Northern France), a plan he had strongly opposed:

Our situation is anyway impossible, so great riscs has to be taken [to achive victory]

(Own translation)

Germany, perhaps rather Hitler, sought to get around the basic strategic defiency of it's position, by the concept of "Blitzkrieg". Which is not about surprise attacks, or disrupting mobillisation or bring about a strategical collapse of the enemy by fast advancement, but is instead defined alone in the floowing "Fuhrer" quote:

IF I cannot win a great war, I will cut that war into small pieces and win those one by one

(Own translation)

Which is, that the concept of Blitzkrig is a "war-concept". Namely to attack and achive local victory quickly with the sole objective to deliver a "fait accompli", which will then be turned into a strategical victory by use of diplomacy (F.ex. Rhinland, Anschluss, checcoslvakia)

The war-politic of Blitzkrig begins to end at Poland, were France and UK, to Hitlers surprise, actually declares the great war, though it's reenvitalised in "Weserubung" (The attack on Denmark-Norway) where the concept is used in regard to the US.

Japan's position was different, but not less hopeless, in the regard that Japan was allready "committed". Japan had been waging war in China since 1933/1937. As Firn and Swerve correctly layed out above, the necessity of war with the US was actualized by Rossevelts embargo politics coupled with unacceptable (for Japan) demands.

The Japaneese surprise attack on Pearl harbour and the simultanious attacks into the South-east, was simply good, but highly riscy, millitary handcraft, based on the decades old Japaneese doctrine that the US navy was the primary enemy of the Emperial navy, and that the only road to victory was a devastating first strike. It's noteworthy that Japan missed it's primary targets in the attack: One or two of The carrier fleet. And as such the attack on Pearl Harbour was far from a full succes.

We can speculate what would have happened if the american carrier fleet had been largely destroyed in the attack (a full succes). One possibility is that the US would have been able to counter attack not earlier than 1944. Couple that with a (by 1941 still likely) outcome on the russian plains to germany's advantage, it's not entirely impossible that f.ex. a diplomatic solution could have neded the war, to the advantage of Japan.

 

[The_Zergling]

In the pacific the same motivations that drove the US into a confrontation with imperial japan still stand, and as Japan rises t reclaim its true place as the leading regional power the US will confront the threat to its hegemony. Truly the US will confront any threat to its hegemony, remember friendships are not eternal, only interests.

I don't doubt that it's possible that very strange things can happen, and that friendships are based strongly on self interest.

However, I would argue that Japan will not militarize easily. First, there is the obvious obstacle in public will, which as far as I can tell is still strongly anti-war, particularly against nuclear states. The right-wing nationalists have certainly done their best to make their voices heard (and the recent North Korean incident helped them somewhat), but they are still a minority by far. Second, it seems that for the most part, Japan is already getting what it wants politically. It has access to most of the resources that it needs, and has the US as a strong military ally against likely adversaries. This has come at the cost of some autonomy of course (such as the sacrificing of Okinawan interests, or shouldering much of the burden for the Gulf War), but overall I feel that most Japanese view the current arrangement positively.

Now, if China is able to truly challenge US power in East Asia, then this may change - much of Japan's comfortable position is due to the United States, and if the US isn't the power that it is now, then it is possible that Japan would try to find an alternative. However, even in those circumstances I don't feel that war with the United States would be a desirable option, particularly from the Japanese perspective. Militarily, there's just a huge difference,and culturally it seems almost unthinkable, given the close relations established since WWII. (I acknowledge that there are real problems, but they don't seem to be worth fighting a war over, in the likes of WWII)

 

[Palnatoke]

In the US japaneese relationship. One can't draw comparisons between the 20ties and 30ties and today.

In the 20ties and 30ties much of the problem vis a vis Japan was it's (rightfull) claim to be considered and treated like a first world nation and then the US reluctance or rather refusal to do that.

That made Japan abandom it's "Do like britain" policy and try to establish her own independent position(which included territorial ambitions on the chineese mainland - something that Japan did ofcourse not have a right to, but after all the americans and Europeans had served themselves well at that table for a couple of 100s years)

To day Japan is integrated into the world economy on an equal footing and it's regarded as a prime first world nation. And if anything the US wants Japan to arm and not disarm like in the 20ties.