Why didn't Japan invade Pearl Harbour or USA?

After bombing Pearl Harbour, why didn’t they invade it too because they could use it as a staging ground for invading USA? The US would take 6 months to get even remotely ready for war. So why didn’t Japan strike at the heart of the enemy (the US in this case) when it was still weak? They did that for Dutch East Indies, British Malaya, Burma, Philippines. So why not USA?

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In summation:

Taken as a whole, it can be seen that a Hawaiian invasion was hardly likely, regardless of the stage of the war. While an attack at the outset of hostilities might have succeeded in capturing the islands, it was strategically unsound, suffered from by horrendous military and logistical difficulties, and was risky to the point of lunacy. A defeat at Hawaii in which either Kido Butai or the amphibious forces involved suffered major losses would cripple the Japanese war effort before it had fairly begun, and make securing the resources of Southwest Asia much more difficult. Given the slender logistical base upon which the historical Japanese campaign was conducted, it is difficult to imagine how Japan would have been successful under such circumstances. An invasion of Hawaii after a victory at Midway was scarcely more realistic in terms of logistics, and had the added detraction of facing a very large, dug-in garrison who had had months to prepare their defenses. The Japanese chances of success in such an operation were minimal.

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Good stuff Norman. The Japanese did try the half step of taking Midway at their height of power, 6 months after the attack on Pearl Harbor…the result was the ending of Kido Butai for all intents and purposes.

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Add to that… look at how the invasion of Attu and Kiska turned out, even though I have read that those operations were an attempt to divert attention from Midway. The Japanese expected that the US Navy would head in that direction and leave Midway exposed.

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Very interesting scenario.

Situation 7 December bombing of Oahu/Pearl could have worked but:
1 Hawaii consist of a bunch of Islands with mountainess and easily defendable terrain.
2 The 6 Carriers could not support the invasion for ever and were needed in other places and moreover had limited supplies.
3 The US would have held on to at least some Islands and started a slogging match. With the Allies interdicting Japanese supply lines.

As for invasions Parshall makes a great case that the Japanese were good at invading weak points and march through jungles. There were not good at defeating an opposed landing like e.d. The USMC later in Iwo.

The Japanese suffered heavily against the very weak Wake Island. MIDWAY in June had 2 Marine defense battalions and on Midway you can’t flank anything. See link to the book.

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great question!
The US were not ready for war at the time all together but neither was Japan in any case capable of seizing more then they eventually did.
Consider the huge amount of territory they needed to defend with their fleet against the USA. Their regular army, fighting since the early 1930’s, however, was well established and equipped in the south east of Asia so logically they would go for easy pickings as they predominantly needed oil and rubber, not a holiday on the beach of Oahu :smiley:

I presume, the main reason for subsequently going for the “Germany First” of FDR, IMHO, was already settled before even Lend-lease Act or Trans Atlantic Charter both were conceived. During the late 1930’s, the biggest fight FDR was engaged in was domestic…against isolationism and even pro-German factions of antisemitic forces, undermining his (already flawed) New Deal politics and his wishes to get in the game on international economics…so: whereas his mind was also focused on beating or at least pressurizing the Japanese Empire, eventually, I believe predominantly, in his heart , FDR was determined to stay in support of the UK and thereby secure a bridgehead to ‘liberate’ Europe in order to establish a solid economic base and eventually dominate both the USSR and China.
All this said and done, let me be clear on my outspoken respect and appreciation to all the US and Allied forces, and even all other forces that endured this dreadful war…men, women and children, regardless of color, country or sides chosen, who gave their lives or limb during this war…Never forget!

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Wow, this is one of the best written articles I have come across. Thanks, Norman!

So tldr; japan wanted to secure resources first (which lie in malaya, the dutch east indies) and then launch an attack on american islands (this never takes place because midway).
Even if they did try to invade say pearl harbor and malaya, the would be overextended and they would not have had the success they had in the early stage of the war.

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You have asked an excellent question. The reason why the Imperial Japanese Army did not consider an invasion of the Hawaiian Islands is the strength of the US Army garrison on Oahu. During the interwar years, the US Army always kept the Department of Hawaii at full strength. On September 3, 1939, the 19,997 officers and enlisted men of the Hawaiian Division is one of only three divisions in the United States Army that is immediately ready for combat operations. They are backed up by the Hawaiian Coastal Artillery Brigade (coastal artillery regiment, 3 coastal artillery battalions, and an antiaircraft regiment.)

The Japanese Consulate will contnuously report on the build up of American forces on Oahu. During the leadup to Pearl Harbor, they will watch the Hawaiian Division be converted into the fully equipped 24th and 25th Infantry Divisions, 298th Infantry Regiment - Separate (Hawaii NG), and 35th Combat Engineer Regiment. The Coastal Artillery is also being transformed into 2 full strength brigades (Defense of Pearl Harbor, Defense of Honolulu) and the reinforced 53rd Coastal Artillery Brigade of 4 antiaircraft regiments.

Due to the strength of the American defenses, the Imperial Japanese Army calculated that it would take a minimum of three full strength infantry divisions plus supporting forces to seize Oahu. Now the problem arises is that Combined Fleet can only support operations for 14 days before they need to withdraw due to the lack of fuel. The IJA rightfully feared that the US Pacific Fleet would just withdraw from the area and run out the clock until the Japanese fleet had to withdraw. This would leave the Japanese soldiers defenseless against Pacific Fleet. Additionally, the IJA also rightfully concluded that the Americans will immediately build airfields on the other seven inhabited Hawaiian islands in the aftermath of Pearl Harbor making it impossible for the Japanese Navy to obtain air superiority and leaving the Japanese soldiers to American air attack. The combination of all of these factors is the reason why the Japanese Army never seriously considered an invasion of the Hawaiian Islands to be possible unless there was a drastic change in circumstances.

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This is a well detailed outline Robert, thanks for sharing, its very much appreciated.

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Welcome to the forum Macdrum and your excellent contribution is greatly appreciated.

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Welcome Robert! Appreciate your question.
My view on the topic is that the Pearl Harbour attack was purely a tactical move to neutralise the Pacific Fleet to get free roaming on the main strategic targets, being, imho, the Dutch East Indies and the peninsula of Malaysia, being rich in oil and rubber, and beyond the reach of the us forces, once the fleet was destroyed…3 aircraft carriers survived and the rest is history.
There was never any interest or necessity to occupy Hawaii or the west coast, simply because there was nothing to gain and everything to loose…again, imho

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I just saw this having been away for while. It occurs to me that the Kido Butai would not have wanted to support any invasion of Oahu even if fuel had not been an issue, given the very cautious nature of Nagumo, the commander. He had refused to launch a third wave at Pearl Harbor, which might have crippled fuel reserves for the US Pacific Fleet, because he was concerned about the missing carriers and worried he might lose the fleet. So I doubt he would have been willing to expose his fleet in any type of invasion. Just a hunch on my part.

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It has to be rembered that Yamamotos overall Strategic goal was to destroy the US fleet and sue for peace. He was fully aware of the industrial might of the US, and immediatly recognized the colossal blunder of attacking without a proper decleration of war. See the splendid japanese film Isoruku Isoroku (film) - Wikipedia

Also the great rivalry between the japanese army and navy must be remembered. The adventure to the south Pacific was seen by the army as a navy thing. The army was so busy in China, that they under no circumstances could provide the 15+ divisions it would require to take and hold Australia. I guess Australia was never in real danger for invasion, and neither was UK in 1940. The logistical and practical reality have been forgotten through the years.

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