Japan invade Hawaii!!!!

Hmmmm.....Going to some data on this.I think the last one on Japanese technology is the most interesting.Sounds like the US fleet went to the Pearl Harbor for all the wrong reasons?? And the Lindberg´s non-interventionist movement? Never heard of that one before...Anyone else?
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Three events involving the sites at Cavite and Heeia, Hawaii, from 1938 to 1941 will strikingly illustrate how truly primitive were the communications which served the Navy's COMINT function overseas. In September 1938, Lieutenant Jack S. Holtwick, then the CINCAF Radio Intelligence Officer, complained to OP-20-G about the lack of electrical communications between the unit at Cavite and the flagship. He said that "it now takes days to obtain COMINT information needed to prepare a daily status report." In 1940, Hawaii commented on tracking Japanese naval vessels during annual maneuvers stating that "the only helpful direction finding came from the Philippine unit by Clipper mail!"96 Finally, on 5 January 1940 Admiral Stark, CNO, requested the Bureau of Engineering to connect the site at Heeia to an Army cable which then terminated at Kailua, eight miles away. Stark also requested the engineers to arrange for an intercom between the communications intelligence unit at Pearl harbor, the Lualualei direction finding site, and Heeia, also by Army cable, using "other than teletype instruments." These arrangements were meant to replace the public party line telephone service. By 7 December 1941, the work had not been done, and with the loss of telephone service in the attack, there were no communications between Heeia and Pearl Harbor (about thirty road miles) except by vehicle!

On 7 May 1940, the U.S. fleet moved its headquarters from San Pedro, California, to Pearl Harbor. The move was undertaken with great reluctance by Admiral James O. Richardson, Commander in Chief, U.S. Fleet. Richardson and most Navy officials who opposed the move thought a fleet anchored in Pearl Harbor would be unnecessarily exposed to Japanese naval strength. President Roosevelt, however, considered the move as a necessary countermeasure to growing Japanese bellicosity. Throughout 1940 Richardson bitterly voiced his objections to relocating his headquarters to Pearl Harbor because it challenged the soundness of U.S. policy in the Pacific. He claimed that Pacific naval offensive -- the heart of the Navy's War Plan Orange -- was sure to fail because the U.S. did not have the capability to support an offensive west of Hawaii. He also noted a factor not considered by the war planners: the U.S. was now vulnerable to attack in the Atlantic and the Caribbean. In January 1941, Roosevelt ordered him relieved. His replacement was Admiral Husband E. Kimmel who, at the same time, was designated Commander in Chief, U.S. Pacific Fleet (CINCPACFLT).

On 7 December 1940, exactly one year to the day before Japan attacked Pearl Harbor, Lieutenant Commander Edwin T. Layton, a Japanese linguist with past experience in OP-20-G, became the Fleet Intelligence Officer, and a few months later, Commander Joseph J. Rochefort, who was the only man in the Navy who was both a cryptanalyst and a Japanese linguist, became OIC of the 14th Naval District's Radio Intelligence research effort.
They quickly established a close working relationship, and the liaison would soon prove immensely beneficial to the U.S. Pacific Fleet.

In one instance Layton's analysis of callsign and address usage, which he had undertaken during 1941 at Rochefort's request, was sent to Washington on the order of Admiral Kimmel.99 His conclusion that the Japanese had begun a military buildup in the Mandate Island (Marianas, Carolines, and Marshalls) was a development which had gone unnoticed by COMINT analysts in Washington, Unexpectedly, rather than foster good relationships between Pearl Harbor and Washington, this episode caused considerable ill feeling toward Layton and Rochefort. It may also have marked the beginning of an unhealthy intramural OP-20-G rivalry between the Washington and Hawaiian centers over the issues of COMINT reporting responsibilities and Japanese intentions which persisted well into 1942.

The COM-14 daily summaries clearly showed that Lieutenant Thomas A. Huckins and Lieutenant John A. Williams, who headed the traffic analysis unit, had solved both the strategic and tactical Japanese naval communication structures. They understood the callsign generation system and were able quickly to reestablish order of battle data after routine callsign changes. This insight permitted unit identifications to the squadron level in ground-based-air and destroyer units.
The capability to exploit these features of Japanese Navy communications lasted until about three weeks prior to the attack on Pearl Harbor when callup and addressing procedures changed abruptly.

http://www.history.navy.mil/books/comint/

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Congress was specific in its finding against the 1941 White House( October 2000 ): Kimmel and Short were cut off from the intelligence pipeline that located Japanese forces advancing on Hawaii. Then, after the successful Japanese raid, both commanders were relieved of their commands, blamed for failing to ward off the attack, and demoted in rank.

President Clinton must now decide whether to grant the request by Congress to restore the commanders to their 1941 ranks. Regardless of what the Commander-in-Chief does in the remaining months of his term, these congressional findings should be widely seen as an exoneration of 59 years of blame assigned to Kimmel and Short.

Roosevelt believed that provoking Japan into an attack on Hawaii was the only option he had in 1941 to overcome the powerful America First non-interventionist movement led by aviation hero Charles Lindbergh. These anti-war views were shared by 80 percent of the American public from 1940 to 1941. Though Germany had conquered most of Europe, and her U-Boats were sinking American ships in the Atlantic Ocean—including warships—Americans wanted nothing to do with “Europe’s War.”
(What?? )

Japanese leaders failed in basic security precautions. At least 1,000 Japanese military and diplomatic radio messages per day were intercepted by monitoring stations operated by the U.S. and her Allies, and the message contents were summarized for the White House. The intercept summaries were clear: Pearl Harbor would be attacked on December 7, 1941, by Japanese forces advancing through the Central and North Pacific Oceans. On November 27 and 28, 1941, Admiral Kimmel and General Short were ordered to remain in a defensive posture for “the United States desires that Japan commit the first overt act.” The order came directly from President Roosevelt.

http://www.independent.org/tii/news/001207Stinnett.html

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Throughout 1941 U.S. radio interception stations kept track of major Japanese ships by listening to messages. Although the messages could not be decoded, they usually could be traced to specific ships because U.S. eavesdroppers knew the Japanese “fists”--the characteristics of individual Japanese telegraph operators--and linked them to certain ships. But in December 1941 the messages stopped--the Japanese fleet had been ordered into radio silence.

The mystery of the “missing” ships worried Lt. Comdr. Edwin T. Layton, intelligence officer on the staff of the U.S. Pacific Fleet commander at Pearl Harbor, Adm. Husband E. Kimmel.

“Do you mean to say,” Kimmel asked Layton on December 2, “they could be rounding Diamond Head [an Oahu landmark] and you wouldn’t know it?”

“I hope they would have been spotted before now,” Layton said.

intelligence officers in Washington did have some general indications of Japanese moves. But for perceived security reasons, the Washington officers declined to share that information with intelligence officers in Pearl Harbor.

In Hawaii the U.S. naval commander, Admiral Kimmel, took minimal steps to increase readiness, sending aircraft carriers to deliver Marine planes to Wake Island and the Midway Islands. The Army commander, General Short, also did little, except to line up his planes in tight groups to protect them against possible sabotage.

http://plasma.nationalgeographic.com/pearlharbor/ngbeyond/stories/story6.html
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The real surprise was not the intentions of the Japanese military, or even the proximate time, it was the ability of Japanese pilots and ordinance to successfully execute the attacks.
There was a shortlist of four targets: the two most likely being Pearl Harbor, where the US Pacific fleet was stationed, and Clark Air Force Base, where virtually all of the US bombers were stationed.What was unexpected was Japanese capabilities.US military intelligence had assessed, based on observation of Japanese air shows, that Japan did not have the capacity to launch torpedoes from airplanes in shallow water. Torpedoes in 1941 were usually deployed in deep water, so their motors could start to propel to the surface before they hit the ocean floor. If Japanese pilots did not have the technology and skill to launch torpedoes in shallow water, the safest place for the US battleships would be in the shallow waters of Pearl Harbor. So, marshaled in the presumably safe harbor, the fleet was kept on an alert 1 status (the lowest of three alerts)

At Clark Air Force base, there could be no possible surprise about Japan's intention. Japan had already attacked the US, nine hours earlier. The US command assumed, however, its bombers were safe because, with the Japanese carriers now known to be in Hawaii, the nearest available Japanese bombers, based in Taiwan, could not reach the Philippines without mid air refueling. And US intelligence had assessed that these land-based bombers could not by refueled in mid-air by Japanese pilots. So the U.S. left its only wing of bombers parked, wing to wing, in the open. What was unexpected was that Japan, like the US, had perfected mid-air fueling techniques. In both cases, the US were surprised, not by the intentions of the Japan, but by its technology.

 

SOME MORE INFORMATION

March 1941

Nagao Kita, Honolulu's new Consul General arrives on Oahu with Takeo Yoshikawa, a trained spy. As the military of both countries prepared for possible war, the planners needed information about the opponent.

The U.S. knew that Hawaii was full of Japanese intelligence officers but because of our constitutional rights very little could be done. Untrained agents like Kohichi Seki, the Honolulu consulate's treasurer, traveled around the island noting all types of information about the movement of the fleet. When the attack occurred the Japanese had a very clear picture of Pearl Harbor and where individual ships were moored.

April

American scientists had developed a machine, code named 'Magic" which gave U.S. intelligence officers the ability to read Japanese secret message traffic. 'Magic' provided all types of high quality information but because of preconceived ideas in Washington some data was not followed up on and important pieces of the pre-attack puzzle were missed.

While the U.S. had all the data needed to arrive at a clear picture of Japanese intentions, the Navy had an internal struggle between the Office of Naval Intelligence and the War Plans Division about which department should be the primary collection office. When the War Plans Division was finally designated the first in line for data, all of the Navys intelligence collection was degraded .

To further complicate this problem the Army had its own intell office, G-2. At times the Army and the Navy did not talk to each other, again reducing the ability to divine Japan's intentions. Finally, Washington did not communicate all the available information that was received to all commands, at times thinking that such a transmission would result in duplication. All in all the U.S. knew that Japan was going to expand its war but the question remained, where? If U.S. Intell people had communicated , preparations for the attack could have been improved.

May

Admiral Nomura informed his superiors that he had learned Americans were reading his message traffic. No one in Tokyo believed that their code could have been broken. The code was not changed.

November

Tokyo sends Saburo Kurusu, an experienced diplomat to washington as a special envoy to assist Ambassador Admiral Kichisaburo Nomura, who continued to seek a diplomatic solution.

On the 16th the first units,submarines, involved in the attack departed Japan.

On the 26th the main body, aircraft carriers and escorts, began the transit to Hawaii.

December 7th

At 0750, Hawaiian time, the first wave of Japanesee aircraft began the attack. Along with the ships in Pearl Harbor, the air stations at Hickam, Wheeler, Ford Island, Kaneohe and Ewa Field were attacked.

http://history.acusd.edu/gen/WW2Timeline/RD-PEARL.html

 

Something the Japanese were very interested in Europe...Somehow..

FAA and the Strike on Taranto

Shortly before 2100, on 11 November 1940, 12 swordfish biplanes took off from the Illustrious. Six carried torpedoes, four carried six 250lb bombs and 2 had four bombs and heavy illuminating flares.All carried extra fuel tanks either in the rear cockpits or slung on the outside.

By 2250 they were approaching Taranto. Anti-aircraft and machine-gun fire rose to meet them. Just off Cape San Vito, the two aircraft with flares swung away to starboard while the first wave of aircraft lined up to attack through the line of Barrage balloons, from the east. As they flew in across the bay, in front lay the battleship Cavour. The second wave which arrived an hour later swung in over Cape Rondinella, but by 0300 all except two aircraft were safely back aboard Illustrious. They had left Taranto in chaos. The Italian battleships Cavour, Littorio and Duilio had all been successfully torpedoed; Cavour was permanently out of action as were the other two for many months. Behind Mare Grande an aircraft hanger had been left blazing and a cruiser damaged by bombs. Of the two Swordfish that failed to return, one crew member had been taken prisoner. The other two were killed during the attack.
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The cost in human life had been surprisingly light and nothing compared to some of the other great naval engagements of the war. The Royal Navy had lost two men killed and two more taken prisoner-of-war. The Italians had lost a total of 40 men; one on the Duilio, sixteen on the Conti di Cavour and twenty-three on the Littorio. The Littorio was to be out of action for five months, the Duilio for six months, and the Conti di Cavour was still being repaired when Italy surrendered. The Trento was out of commission for months from the damage of the single unexploded bomb. Perhaps as important as the physical damage done to the Italian warships was the psychological damage. Taranto, the main offensive base of the Royal italian Navy had been shown to be insecure. The day after the raid Supermarina ordered the Vittorio Veneto and the Giulio Cesare to sail north for the port of Naples, where they would be safer. They would also be so far away from the important sealanes as to pose almost no threat to the British. The Italian fleet did fight other actions against the British, the largest being at Cape Matapan, but the raid on Taranto effectively ended any hope the Italians had of actually turning the Mediterranean into the Mare Nostrum so beloved of Fascist propaganda. For the Royal Navy it had been a good night's work

http://www.geocities.com/Broadway/Alley/5443/tar3b.htm

 

This changes the course of the war in a huge way. Had the Japaneese invaded Hawaii then FDR has a hard time convincing the country to go after Germany first. In this What-If USA goes after Japan first and defeats Japan in 1944, but suffers more casualties because no A-Bomb is ready and has to invade Japan. Germany still gets crushed by the Russians.

 

Didn't FDR decide to go after the Japanese first?

If we want to get technical, wouldn't the Doolittle raid be the first US offensive action of the war?

I had the impression that the US did in fact go after Japan first...

 

Thinking about it it probably was one of the first offensive operations the U.S took in the Second World War. Its got me thinking now actually. There might of been air attacks on some of the Japanese islands before the Doolittle raid but im not entirely sure.

Jet

 

Yeah... I'm kind of just guessing- don't really want ot look this up right now.
But as far as the emphasis goes, it certainly does seem that American efforts were directed towards Japan first, and Germany second. At least in the first couple years of the war- with Pearl Harbor still fresh.
Correct?

 

The American government agreed that the Germans were a bigger threat. However, alot of Americans wanted to attack Japan after what they did to them at Pearl Harbour. But the first military actions of the war were done in the Pacific theatre. I guess its only natural that the Americans wanted to go after the Japanese straight away.

Jet

 

I had the idea that Roosevelt and Churchill together thought First Europe then Japan and Pacific Ocean...gotta check on that.

Anyway, here´s FDR´s speech which includes the data how Canaris probably got the 60,000 planes per year figures for the US that got Hitler mad...

THE ANNUAL MESSAGE TO CONGRESS

Delivered by President Franklin D. Roosevelt on January 6, 1942

http://history.acusd.edu/gen/WW2Text/fdr_speech_420106.html

I have just sent a letter of directive to the appropriate departments and agencies of our Government, ordering that immediate steps be taken:

1. To increase our production rate of airplanes so rapidly that in this year, 1942, we shall produce 60,000 planes, 10,000 more than the goal set a year and a half ago. This includes 45,000 combat planes-bombers, dive bombers, pursuit planes. The rate of increase will be continued, so that next year, 1943 we shall produce 125,000 planes, including 100,000 combat planes.

2. To increase our production rate of tanks so rapidly that in this year, 1942, we shall produce 45,000 tanks; and to continue that increase so that next year, 1943, we shall produce 75,000 tanks.

3. To increase our production rate of anti-aircraft guns so rapidly that in this year, 1942, we shall produce 20,000 of them; and to continue that increase, so that next year, 1943, we shall produce 35,000 anti-aircraft guns.

4. To increase our production rate of merchant ships so rapidly that in this year, 1942, we shall build 8,000,000 deadweight tons as compared with a 1941 production of 1,100,000. We shall continue that increase so that next year, 1943, we shall build 10,000,000 tons.

These figures and similar figures for a multitude of other implements of war will give the Japanese and Nazis a little idea of just what they accomplished in the attack on Pearl Harbor.

[ 19. February 2003, 04:48 AM: Message edited by: Kai-Petri ]

 

http://www.valourandhorror.com/DB/BACK/Diepptxt.htm

Though American military officers were in England as observers as early as October, 1940, the World War II alliance between the English-speaking nations began to take definite shape only in January, 1941. This was the month when American and British military officers met in Washington for conversations that became known as ABC-1. The agreements reached--that the two nations were to maintain joint planning staffs in Washington and London, and that, if forced into war with both Japan and Germany, the United States would join Britain in defeating Germany first--started the chain of events that led to the eventual cross-Channel invasion and victory in Europe. It was two months later, in March, when Congress passed the Lend-Lease Act, which authorized the United States to provide war materials for nations under Axis attack. By June, with the American observers in London having become the Special Observer Group, and the British having sent representatives to Washington, the two countries were in close liaison. Though the United States still was not at war, American troops replaced British troops in Iceland in July, 1941, and later in the summer began to construct naval and air bases in the United Kingdom, ostensibly for British use.

as American and British military leaders met in Washington in a series of conferences known as Arcadia (December, 1941-January, 1942), they reaffirmed the ABC-1 decision to remain on the strategic defensive in the Pacific, while defeating Germany first. They decided to wear down German resistance in 1942 by air bombardment, by assisting the USSR, and by trying to gain the entire North African coast, before initiating, in 1943, a large-scale land offensive against Germany across either the Mediterranean Sea or the English channel. They also created the Combined Chiefs of Staff (CCS), consisting of the United States Joint Chiefs of Staff and the British Chiefs of Staff, as the body to assist and advise President Franklin D. Roosevelt and Prime Minister Winston Churchill on the direction and conduct of the war. The most prominent members of the CCS were Gen. (later General of the Army) George C. Marshall, United States Army chief of staff, and Gen. (later Field Marshal) Sir Alan F. Brooke (later 1st Viscount Alan Brooke), chief of the Imperial General Staff. Because the CCS met only periodically, the American and British members did the detailed work of planning separately. Those most concerned with planning a European invasion were the Operations Division (OPD) of the United States War Department and the British Combined Commanders (the senior ground, naval, and air officers, together with Lord Mountbatten).

 

You are right Kai-Petri, FDR and Winston Churchill both agreed that the Germans were a bigger threat and that they would go after the Nazis and then go up against Japan.

Jet

 

Nice... interesting stuff, Kai. I would have thought that the Japanese were the priority, but apparently not. Interesting that it appears that here is more evidence of FDR's willingness to go to war despite the American people being undecided. If FDR make that agreement in 1941 to help the British defeat the germans "if the US was brought into the war", that would suggest to me that he was certainly ready to join the war against the Nazis.

I guess the first strikes against the Japanese must have been more due to logistics and prestige. I think that after Pearl Harbor, the Americans needed some kind of victory against the Japanese for morale more than anything else.

 

Can't remember the specifics and my research is at my folk's house. But, the war in the pacific was the main focus of us media, believe it or not. By media, I mean Life magazine, time magazine, hollywood, etc. That was the topic of a paper I wrote back in 98/99, but of course I've had alot of beer since then, so memory of it is a bit hazey.

As far as the US is concerned,the pacific war did of course last longer, and we had more casualties there, if my brain remembers facts from 5 years ago correctly......... So often when researching with primary sources, it SEEMS that US emphasis was in the pacific

[ 19. February 2003, 09:27 AM: Message edited by: Doc Raider ]

 

It is debateable who was the bigger threat. For the British the Germans were, but for America the Japanese were. The Japanese were a far more vicious fighting force than the Germans, in the sense that the Japanese would fight to the last bullet and the last man. But the thing is that I believe that FDR decided to take priority in Europe because the Americans were in no threat of being invaded. The British were and they needed help, and the Americans had to help their ally.
I think you're right Crazy D, the Dolittle raid was nothing more than a morale booster and gained nothing strategically. But it did send a message that the Americans were still alive, and they would fight.

Jet

 

Ok, here´s some more of the Doolittle boys:



Lieutenant Colonel James H. Doolittle, USAAF (front), leader of the raiding force, wires a Japanese medal to a 500-pound bomb, during ceremonies on the flight deck of USS Hornet (CV-8), shortly before his force of sixteen B-25B bombers took off for Japan. The planes were launched on 18 April 1942.
The wartime censor has obscurred unit patches of the Air Force flight crew members in the background.



Lieutenant Colonel James H. Doolittle (left front), leader of the attacking force, and Captain Marc A. Mitscher, Commanding Officer of USS Hornet (CV-8), pose with a 500-pound bomb and USAAF aircrew members during ceremonies on Hornet's flight deck, while the raid task force was en route to the launching point.

http://www.history.navy.mil/photos/events/wwii-pac/misc-42/doolt-p.htm

 

I still think it's possible the Japanese could have invaded Hawaii even IF it would just have been re-invaded later.
As for how, I noticed someone talking about planes having to attack the beach AND attack the ships. Well I think the answer is quite simple; launch the invasion into the port itself. Japan has had experience launching amphibious landings on ports and harbours before, from their Chinese campaigns. And just imagine the effect on the Americans stationed there. Everything exploding around them, and suddenly they hear the scream of hundreds of Japs running around the corner at them. Also, the Japs had plenty of spies in Hawaii, they knew where every ship was going to be and where facilities were, taking the same information to plan an amphib. landing would have been comparitively easy. I don't doubt that if the Japanese had invaded Hawaii that they would have succeeded, not only in destroying the USN but in denying it the use of its main Pacific fleet base and the entire turn of events in the Pacific would have been much different. the US wouldnt have been able to stage the ambush at Midway or to even protect Australia or the Phillipines, the Commonwealth would have been alone in their fight and with pressure in Europe they would either abandon the Pacific or just be defeated. Then the door would be open for Japanese expansion into SW Asia and India, and perhaps threaten the British in the Middle East and thus North Africa.. yadda yadda!

I know these are probably "fantasy" theories but all thoughout WW2 there were many "surprises".

As for supply lines and logistically supporting an invasion of Hawaii, I doubt it would have been that hard for the Japs. First of all they had a very broad network of supplies to all their battles throughout the Pacific, and that was under constant USN superiority. Without the USN's main base at Pearl the Japs would have a much larger "safety zone" in the Pacific and be able to supply themselves more successfully.

 

The key to a successful Japanese invasion of the Hawaiian Islands, I believe, would have been AIR and NAVAL supremacy. That is, the Japanese would have to knock out both American naval AND air forces in the area in order to have a feasible chance at even invading Hawaii.

Assuming, however, that the IJN sucessfully eliminated every American fleet and air force in the Hawaii area, the Japanese would have to secure the Hawaiian Islands (or at least the critical military and population centers in Hawaii) before the US could mount an effective counter-offensive from the West Coast. Japan's best opportunity for invading Hawaii would've probably been in 1942, when American military forces were at their weakest in the Pacific. Invading Hawaii, however, would've required considerable Japanese forces, forces that, as several posters have already mentioned, were already committed to military operations in Asia and the Western Pacific. Substantial delays or losses from any of these operations could have easily jeopardized Japan's ability to launch an effective invasion against Hawaii at all, let alone during 1942.

Finally, assuming that Japan invaded Hawaii with substantial ground forces and with air and naval supremacy in 1942, the questions come down to how long and how difficult it would have been for Japan to seize Hawaii. One possibility would be that Japan could try to seize some of the less defended neighbor islands first (e.g. Kauai or the Big Island) and build airbases and resources on these islands before invading Oahu, where the vast majority of American military forces and facilities would most likely have been concentrated. This probably would have taken too much time, however. Japanese fleets blockading Hawaii would have then faced a grueling naval war of attrition with American fleets sailing from the West Coast or Panama. With geography and resources on their side, American ships would more than likely break the Japanese blockade, paving the way for American forces to invade any Japanese-held islands in Hawaii.

The other, and probably more feasible option, would be to launch a rapid aerial and amphibious assault on Oahu before securing the neighboring islands. This would've involved the use of paratroop/commando units to seize key areas near the invasion beaches (a la Operation Overlord) followed by a powerful amphibious assault. This of course would've also required elaborate deception tactics in order to fool the Americans as to where the actual assault would take place on Oahu. Assuming that the amphibious assault goes well, the Japanese would then need to secure key American military bases and facilities in the Fort Shafter and Pearl Harbor areas. The Americans would've obviously foreseen this situation, and would've heavily fortified these areas accordingly. Invading Oahu would've almost certainly resulted in heavy Japanese losses without naval and air supremacy.

To sum up, invading the Hawaiian Islands would not have been impossible for Japan to accomplish, but it certainly would've been very difficult. Invading Hawaii would've required good timing, speed, and air and naval supremacy. Surprise also would have been critical. As the Battle of Midway illustrates, the loss of surprise could easily turn any Japanese invasion of Hawaii into a disaster.

These scenarios do not account for everything that could've gone well (or wrong) for Japan in invading Hawaii. If the U.S., for example, was forced to commit greater forces and material to Europe and the war against Germany (e.g. if Russia collapsed or Britain was invaded by the Nazis), the U.S. would've been forced to concentrate their limited military forces in the Pacific on the West Coast and Panama Canal. This certainly would've made invading Hawaii alot easier for Japan. Even if such a scenario did occur, however, American forces left in Hawaii would have put up a spirited defense. Hawaii's large population of Japanese and Japanese-Americans are a big question mark. If the "Niihau Incident" is any indication, Japanese residents could've played a significant factor in facilitating any Japanese invasion of Hawaii (assuming that these people believed that Japan, not the USA, was going to win the battle for Hawaii).

In any case, I believe that the Japanese would've needed alot of men, ships, and planes in order to sucessfully invade the Hawaiian Islands. They would've also needed alot of luck.

 

No need to revive a 6-years-dead thread.