# Isoroku Yamamoto (Speculation)



## Ex-Dragoon (30 Aug 2008)

1) Had he not been shot down by USAAF P38s in 1943 what would have been the outcome of the War in the Pacific?
2) Had he survived the war, would the Admiral been captured, tried as a war criminal and executed?
3) If he was not tried and executed would he have cooperated with MacArthur based upon his fondness of the US in the prewar years?


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## Bearpaw (30 Aug 2008)

These are interesting questions----here are my best guesses:

1) No essential difference----Yamamoto's continued survival would have made some of the later battles more difficult for the Americans. The American's huge advantage in ship and aircraft production, better aircrew training schemes, better ship designs(damage control), and the advantage of retaining Hawaii as a forward operating base made their victory in the Pacifac inevitable.

2) Having read a couple of biographies of Yamamoto, I would think that he would not be taken alive.  If he remained alive at the Japanese surrender he would likely have committed ritual suicide well before capture.
If he had been captured alive, it is almost certain he would have been tried as a war criminal and executed. I am fairly sure he would have had a similar process that befell General Yamashita.

3) Yamamoto's cooperation or not would not have been of much importance at that point.

Another much more difficult question which I would like to add to this list is the following:

When Yamamoto was ordered to prepare an attack on the Americans he made a very bold strategic decision to attack Hawaii----should he also have tried to invade Hawaii at the same time? How much difference would a successful invasion of Hawaii have meant to the war?


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## TCBF (30 Aug 2008)

- I doubt they had the troops to do it.  The bulk of their army spent the war fighting in China. What they could spare was taking Hong Kong and Singapore.


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## Bearpaw (30 Aug 2008)

I think the problem was an overly complex plan for the start of the war with divided strategic goals. In addition to it's attack on Pearl Harbor, Japan launched near simultaneous invasions of Malaya,Thailand, Hong Kong, and the Philippines.  Had they delayed their attack on the Philippines, they could have had the shipping (about 80 transports) and 120,000 men from first-line units available from that source alone. The cost of delaying an invasion of the Philippines would have been a better organized defence but the fall of the Philippines would be inevitable.  

I am not sure if the Japanese ever weighed this option in their planning---there is not very much information available on this issue.

Japanese strategy tended to overly complex plans several times in the war ---- initial invasions, Midway, defensive actions near Philippines later in the war, invasion of Burma.


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## exspy (31 Aug 2008)

Ex-D and Bearpaw,

I agree, a very interesting topic, and I have to agree with Bearpaw on this.

1)  Absolutely no difference to the outcome of the war in the Pacific.  I don't think his leadership would have changed the outcome of the Battle of the Philippine Sea or in the defence of the home islands.

2)  Tried as a war criminal and executed.

3)  Had he not been executed Yamamoto's jail term for war crimes would have rivaled that of Rudolf Hess in Spandau.  I cannot envision any situation in which Yamamoto would not have been tried and allowed to live as a free man.  Therefore he would not have been in a position to either help or impede MacArthur's administration of post-war Japan.  Besides, MacArthur knew that the key to winning over the Japanese people was the Emperor.

Finally, yes he should have tried to invade the Hawaiian Islands.  If the Japanese Army could afford the troops for the Aleutians in 1942 than they should have tried for the direct approach in the first stages.

All speculation and hindsight on my part however.  At the end of the day the sleeping giant filled with a terrible resolve was going to win the war, Yamamoto notwithstanding.

Dan.


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## ExSarge (5 Sep 2008)

Interesting topic, I have to agree with the majority Yamamoto’s continuing survival would have had little impact on the remainder of the war. By 1943 the tide had turned and Japan was firmly on the defensive. The war may have been prolonged by a few months at best, with a higher causality count at the end. Yamamoto’s fate; He was seen as a prime architect of the Pearl Harbour attack and would have paid the price the American public demanded! 

Should the Japanese of followed up the attack on Pearl Harbour with a landing and occupation of the Islands. This is a favourite topic for “what if” historians. The question is complex as is the answer. However in a nut shell, the Japanese did not have the shipping to sustain an outpost so far removed from their main defensive perimeter. The seizure of the Aleutians (which was never intended as more then a feint and a distraction) proves that point. Had they tried it probable changed the course of the war in the Pacific, taking the pressure off the Philippines and Malaysia as shipping was diverted. American submarines would have had a field day taking out transports. The topic of Japanese method of sailing merchant shipping and defensive (or lack there of) tactics has filled volumes. 

A more interesting question is “During the attack what if the tank farms had been targeted as well as shipping at Pearl Harbour?” Had the focus of the attack shifted from shipping and airfields to fuel and repair facilities it would have made the Islands untenable as a fleet anchorage during the crucial first six months of the war. This would have required the Americans to withdraw fleet support from Hawaii to the west coast. Had the Japanese continued their raid attacking west coast tank farms etc the whole course of the war may have been altered.


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## Danjanou (5 Sep 2008)

Harry Turtledove who has written quite a few alternate histories has a two book series dealing with a follow up invasion of the Hawaiian Islands 

Days of Infamy 
http://en.wikipedia.org/wiki/Days_of_Infamy
http://www.amazon.ca/Days-Infamy-Harry-Turtledove/dp/0451213076/ref=sr_1_32?ie=UTF8&s=books&qid=1220621672&sr=8-32

And the sequel  

End of the Beginning 
http://en.wikipedia.org/wiki/End_of_the_Beginning
http://www.amazon.ca/End-Beginning-Harry-Turtledove/dp/0451460782/ref=pd_bxgy_b_text_b?ie=UTF8&qid=1220621672&sr=8-32

Both of which I recommend. The number of troops used for the invasion/occupation of the islands is surprisingly small, as the Japanese have total air superiority. The Carrier group does not withdraw and catches a couple of the US carriers and sinks them. Later a sort of battle of Midway takes place several thousan nautical miles east of where it actually did and the US lose. By 1942 have lost all their carriers as well as battleships in the Pacific and are forced to transfer more ships form their Atlantic fleet to protect their weest coast from hit and run raids thereby slowing down the war effort in Africa and Europe ( think no Torch/Husky).
Eventually the US will win and retake the islands and move west to retake the Philippines etc but at a much later date and a greater cost. 

A quick look att eh books and it appears Turtledove used the invasions (japanese in 1942 and US in 1944) of the Phillipines as his templates complete  to a death march of US prisoners to create these books,
BTW the Japanese very rarelt of numbers on the ground, relying on superior tactics, and air/naval superiority. IIRC they took Malaya and Singapore with 3 Divisions, the British. Australian, indian defenders had 5 Divisions there althouhgh most were green troops. Finally they never invaded Thailand as it was allied to Japan.


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## Bearpaw (5 Sep 2008)

Exsarge:

Yamamoto considered the failure to send in a third strike against the fuel and repair facilities one of the
greatest blunders of the war.  In fact this blunder directly contirbuted to the later battle of Midway by enabling the quick repairs on a damaged aircraft carrier(Yorkton??).

I am not so sure that an immediate invasion would not have been successul----the invasion fleet and forces for the Philippines could have been used for Hawaii---there was a fair number of idle Japanese divisions in Manchuria that could have be diverted over time to rebuild an invasion force for Philippines.
I really think the decision on an immediate invasion of Philippines was a gross strategic blunder---what was needed was the reduction of US air power---this was done and the containment of the small remaining USN presence in the Philippines.  Much of the Asiatic fleet had been redeployed to the South Philippines on Nov.18----some of the subs were deployed to Formosa and off N. Philippines. (I am researching this thanks to your comment).  I will also look into your comments about the tank farms on the US West coast.

Danjanou:

Thanks for the comments about Turtledove's books---I am an SF buff but have never read any of his stuff--I will read these books in the near future.  From your brief description I think that Turtledove's scenario is not too far different from some of my own musings on this topic.

Bearpaw


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## ExSarge (5 Sep 2008)

Bearpaw,

I don’t dispute that the troops needed for an invasion/occupation of the islands were available. My contention is only that the Japanese lacked the ability to keep them resupplied. The Hawaiian Islands were well outside their defensive perimeter and Japanese merchant shipping was already stretched to the max. Combining that with their attitude to convoy protection (defensive in nature and therefore alien to their offence doctrine) and you have a recipe for failure. American submarines would have had a field day taking out resupply shipping. If you look at the historical record you will see that Japanese merchant shipping was almost completely wiped out by 1945. Even as early as 1942/43 they were forced to use warships in forward areas as transports to make up for a lack of merchant shipping.

Had the Japanese continued the raid after attacking Pearl and the raiding force moved on to the west coast of the United States and Canada the course of the war might (and I stress the word might!) have been much different. Attacks such as delivered at Pearl on fuel facilities and port installations would of reaped rewards out of all proportion to the actual damage done. Public outcry and political pressure from local regional and state representatives would have ensured the fleet was pulled back and in conjunction with military assets used to protect the coast. If you look at what defensive measures were put into place along the west coast of both countries (to include the shameful forced removal of US and Canadian citizens of Japanese decent) as a result of the Hawaii attack, you can guess what they might have done for an actual attack on the coast. The Navy was and is always conscious of its logistics tail. A fleet without fuel or port facilities to conduct resupply or repairs cannot be sustained in a combat environment. Those assets must be protected if the fleet is to be effective. Even if the Japanese lost half the attacking force the results would have been worth the losses. It would have changed American priorities and possible delayed effective offensive operations by a year.


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## Bearpaw (9 Sep 2008)

I read the two books by Turtledove----the first one "Days of Infamy" is quite interesting---I recommend it as a good starting point for thinking about a Hawii invasion.  There are a few points that I disagree with Turtledove on but he has all the essentials covered.  

The second book "End of the Beginning" is more problematic----I suspect it would have taken 3 years at least before the US to re-invaded Hawaii.  Turtledove assumes that IJN would have passively sat in Hawaii and waited for the inevitable invasion----incapacitated by a lack of fuel and transport.  Assuming Japan did not deviate from its actions in the rest of South-East Asia and  allowed the US to establish submarine bases at Fremantle and Brisbane, then Hawaii would have easily been retaken. 

What happens if the IJN uses its submarines(with outstanding long range) to mine the approaches to San Diego, Panama Canal, San Franciso, ..... Brisbane, Fremantle?  The submarine force of the IJN played a relatively passive role in WW2----very few attacks on Allied shipping---mainly used in a fleet and base screening role. A more aggressive role for the IJN submarines may well have shielded their merchant fleets to some degree.

In any case the immense capacity of the US war production would have eventually prevailled---unless Japan was prepared to use the biological weapons that had been developed by early 1945.  This could have bought some time for Japan but the atomic devastation later wreaked in Japan would have been much worse.

Bearpaw


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## Ex-Dragoon (9 Sep 2008)

Try this book by Douglas Niles and Mike Dobson:
MacArthur's War: A Novel of the Invasion of Japan


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## Danjanou (9 Sep 2008)

Bearpaw

That was fast. I agree with your points re the second book BTW. I guess he was shooting for a short series for a change and needed a quick happy ending.

Re fictionalized accounts of the planned Operation Olympic and Operation Coronet
I also recommend

Lighter Than A Feather by David Westheimer 
http://www.amazon.ca/Death-Lighter-Than-Feather-Skates/dp/0929398904/ref=sr_1_1?ie=UTF8&s=books&qid=1220992114&sr=8-1

And to a lesser extent

The Burning Mountain by Alfred Coppel
http://www.amazon.ca/Burning-Mountain-Alfred-Coppel/dp/0727848844/ref=sr_1_5?ie=UTF8&s=books&qid=1220992258&sr=1-5


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## dapaterson (9 Sep 2008)

Interesting .  I recently returned from Hawai'i and that was my immediate take-away from the attack on Pearl harbour - the Japanese destroyed some of the combat power, but left the force projection platform intact.  The tank farms, supply depots, and R&O facilities should have been the objectives of the raid; they would have denied or delayed the American use of Hawai'i as a jumping off point for the Pacific campaign.


TANGENT WARNING
There's another good lesson from that attack (on the American side).  When new equipment comes into service, it's the junior personnel that will have the most familiarity with it, so pay attention to what they say.  The results of the attack would have been dramatically different if the early radar warnings had been heeded instead of ignored.


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## 1feral1 (9 Sep 2008)

I think for the get-go (7 Dec 41) Yamamoto knew that Japan was deemed to lose the war in time, as he was quoted 'we have just awakened a sleeping giant'  (referring to the USA)or words to that effect.

In 3 yrs, 10 months later, it was all over.

OWDU


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## Bearpaw (11 Sep 2008)

Yamamoto was really let down by his tactical commander Adm. Nagumo when he failed to take the opportunity to destroy the tank farms, submarine base, drydocks and repair facilities, supply depots and other shore facilities.   Nagumo was blinded by his tactical success in the first two airstrikes AND the fact he had taken no losses of major ships---he was contented to win the battle but lose the war!  Nagumo was really a battleship admiral---the extensive damage done the the US battleships in Pearl Harbor blinded him to the strategic victory which still remained to be won(even in the no-invasion plan).  
The only reason NOT to destroy the Pearl Harbor infrastructure is a non-invasion strike plan.  These facilities were probably more important than the ships that were destroyed or damaged.

Without the support of Pearl Harbor, the battle of Midway would have been a much closer affair(likely 2 US carriers vs the 3 that were actually used) if the battle took place at all.  

In a certain sense the US Navy had a major problem solved by the attack---no disrespect for the heavy US casualties intended---in the late 1930's up to Dec.7,1941 there had been a tense dogfight among the top admirals of the USN---Carrier Admirals vs. Battleship Admirals.  This internecine warfare had seriously impeded the building program for the USN: battleships or carriers?.  Pearl Harbor put that argument to rest permanently. Only the battleships nearing completion or substantially built were completed---the rest were scrapped in the construction yards.

TO THE MAIN ISSUE

How could  Yamamoto's limited no-invasion plan be amended to produce the strategic set-back for the US that Yamamoto knew was needed for Japan to have a hope for a successful war?

I think that problem actually is much deeper than just the no-invasion plan.  Yamamoto was too good an admiral not to have forseen how the US would react and how it would operate in the central Pacific.
In the 1920's, 1930's and even though World War II, Japan suffered from divided strategic command.
An intense inter-service rivalry (the US problems(Army vs Navy) were pale in comparison) prevented Japan from strategically focussed plan for the start of the war.  In 1941, the Japanese Army was in ascendancy----most of the actions on Dec. 7, 1941 were ARMY-centred operations----the IJN just supplied assistance/transport.  This divided strategic leadership was at the root of Japan's problems and had profound strategic consequence before the first shot had been fired

DISPERSION OF EFFORT

There were too many initial side-invasions of little strategic or economic(oil,steel,rubber,..) consequence.

1) Hong Kong could have been left for invasion much later---it was basically a self-feeding prison camp for the Allied Forces(including Canadians) that had been foolishly sent there as reinforcements.
2) The Philippines was bereft of natural resources needed by Japan---it would have sufficed to knock out the airpower, destroy the Subic Bay naval base and mine approaches, destroy the Cavite dockyard and submarine base and mine Manila Bay.  These goals could have and were partially accomplished by strong air attacks from Formosa(Taiwan) and Hainan Island---they could even have been later supported by the airgroup based in Saigon(tasked versus Malaya).
The US had already seen in early November that the Philippines was strategically indefensible---the USN was largely ordered out of the Philippines on Nov. 18.
The Japanese wasted too many of their soldiers(130,000) and transport capacity(80 ships) in launching an immediate invasion of the Philippines. 
3) Some of the actions against small island groups in South Central Pacific, except for invasion of Guam, should have been delayed.  

NO FOCUS ON ADVERSARIES SUPPLY LINE or LINES OF ADVANCE

1) The supply lines and support bases of the US should have and could have been driven right back to North America(I will post more on this later)

2) Advances should have been made toward the South Central Pacific and to Indonesia in a way that would prevent Australia and New Zealand becoming American bases of operation.(more on this later)

3) The advance to Burma should have been halted once the Burmese oilfield were captured.  Britain was in no strategic position to recover them---by letting the Japanese advance on the British Forces in the mountains of Assam was exactly the wrong thing to do.  The Japanese should have force the British to transit Assam to try to retake Burma.  The RN in the Indian ocean posed no real threat to Japanese control of Singapore and Indonesia----they could have been neutralized by mining and submarine warfare.

Had Yamamota been the Supreme Commander of ALL Japanese forces and been able to direct the overall strategy of the war, I think he may well have tried what I will outline in the next posting to address point 1) above.

ExSarge correctly pointed out in an earlier posting the lack of Japanese transport capacity.  The problem was not only a lack of transport, but what they had was not well utilized.  

Another of ExSarge's points was the US submarine campaign against the Japanese transports----this was true in 1944 and 1945----one of the my main points in the next posting is to show how the bases supporting those subs could have been driven back to North America in the Pacific and probably back to South Africa and Western India in the Indian Ocean.  The Japanese were much more capable of long range submarine warfare in the first 2 years 1942-1943 than the US was---for some reason I have yet to discover they never utilized the superior range and weaponry of their subs.

Bearpaw


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## a_majoor (12 Sep 2008)

The divide between the Imperial Japanese Navy and Army was driven by the argument over which region could best supply Imperial Japan with strategic resources. The Army tended to look at mainland Asia and Siberia in particular, but that plan was hampered by the lack of capital to develop and exploit these resources (even without a military dimension to securing them). The IJN argued that taking the territories of the European Empires provided both developed resources and manpower for quick exploitation by the Japanese Empire.

In either case, the Hawai'in Islands were not relevant to the _Japanese_ plans, except as the forward base of a potential (and eventually actual) enemy force. As noted, the Japanese really didn't have the resources to devote to invading or occupying Hawai'i, and taking out the fuel tank farms would have set back the American war effort, but not changed the eventual outcome. The counterfactual history would have VJ day in late 1946 or early 1947 (and the European war might have also suffered similar delays).


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## TCBF (12 Sep 2008)

- The end may have differed if Japan had more freedom of action to continue her atomic weapons programs. The final decision may have been the same, but the final death toll MAY have been higher.


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## Sito Origami (13 Sep 2008)

dapaterson said:
			
		

> TANGENT WARNING
> There's another good lesson from that attack (on the American side).  When new equipment comes into service, it's the junior personnel that will have the most familiarity with it, so pay attention to what they say.  The results of the attack would have been dramatically different if the early radar warnings had been heeded instead of ignored.



I wonder about this. The naval vessels would have taken time to get moving, but Pearl Harbor only had one exit, so they would have been trapped in the harbor allowing little chance for escape. How many U.S. aircraft could have been airborne to defend the fleet, and how much (effective) anti-aircraft fire could have been put up to deter the attackers? All interesting questions. I think considerable damage could still have been done to the U.S. battleships, but the raid would simply have been much more costly to the Japanese pilots. They were prepared to die in the attempt. The cascading effects would have been perhaps poorer performance at the Coral Sea had their good pilots started being siphoned off in December 1941, perhaps the Battle of Midway never got fought - meaning no great climactic turning point - or just as likely Midway went ahead, and things ended up just as they did in June 1942 at the status quo.


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## Ex-Dragoon (13 Sep 2008)

I did not think Japanese pilots ascribed to the kamikaze philosophy until later in the war


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## Sito Origami (13 Sep 2008)

Ex-Dragoon said:
			
		

> I did not think Japanese pilots ascribed to the kamakaize philopsy until later in the war



You are correct, they did not; that was introduced in 1945. But you're confusing willingness to die with the formal practice of kamikaze units. They are not the same thing.


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## Blackadder1916 (15 Sep 2008)

Sito Origami said:
			
		

> I wonder about this. The naval vessels would have taken time to get moving, but Pearl Harbor only had one exit, so they would have been trapped in the harbor allowing little chance for escape. How many U.S. aircraft could have been airborne to defend the fleet, and how much (effective) anti-aircraft fire could have been put up to deter the attackers? All interesting questions. I think considerable damage could still have been done to the U.S. battleships, but the raid would simply have been much more costly to the Japanese pilots.   . . .



The premise that if the reports of junior (radar) personnel had been heeded, the outcome of Dec 7 may have been significantly different is a bit of a red herring.  While it is true that the report of a radar sighting was misinterpreted to be 'perhaps an incoming flight of B-17s', it must be recognized that the 'Information Center' (located at Fort Shafter) that received the report was basically shut down for Sunday routine and the only pers on duty were a switchboard operator and the duty officer (an inexperienced Lt. who had only been there a few days).  The first radar sighting was made at 0702 and the duty officer made his decision that further action was not necessary at approx 0720.  By 0740 the Japanese had begun their attack run (early due to error) at Ford Island and Hickam Field and the order to begin the general attack was sent by 0749.  It should also be considered that, while the Army was "ignoring" the radar reports, the Navy was "ignoring" the reports of submarine contact from the WARD.

What was probably the greater error (re the radar) was inadequate air defence C3 as well as poor Army/Navy liaison and a mindset (perhaps more so in the Navy) that while war was expected, they did not expect the Japanese to show up at Hawaii and believed that the fleet would be at sea when they would meet and engage the enemy.  Though the deployment of radar on Oahu was probably not the most professional due to an unfamiliarity with this new technology by many higher in the food chain, from a practical aspect, the only action that may probably have been taken (should the radar report had been heeded) would have been to move up to Alert No. 2 or 3, disperse planes on the ground and break out ammunition.


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## Sito Origami (15 Sep 2008)

Blackadder1916 said:
			
		

> The premise that if the reports of junior (radar) personnel had been heeded, the outcome of Dec 7 may have been significantly different is a bit of a red herring.  While it is true that the report of a radar sighting was misinterpreted to be 'perhaps an incoming flight of B-17s', it must be recognized that the 'Information Center' (located at Fort Shafter) that received the report was basically shut down for Sunday routine and the only pers on duty were a switchboard operator and the duty officer (an inexperienced Lt. who had only been there a few days).  The first radar sighting was made at 0702 and the duty officer made his decision that further action was not necessary at approx 0720.  By 0740 the Japanese had begun their attack run (early due to error) at Ford Island and Hickam Field and the order to begin the general attack was sent by 0749.  It should also be considered that, while the Army was "ignoring" the radar reports, the Navy was "ignoring" the reports of submarine contact from the WARD.
> 
> What was probably the greater error (re the radar) was inadequate air defence C3 as well as poor Army/Navy liaison and a mindset (perhaps more so in the Navy) that while war was expected, they did not expect the Japanese to show up at Hawaii and believed that the fleet would be at sea when they would meet and engage the enemy.  Though the deployment of radar on Oahu was probably not the most professional due to an unfamiliarity with this new technology by many higher in the food chain, from a practical aspect, the only action that may probably have been taken (should the radar report had been heeded) would have been to move up to Alert No. 2 or 3, disperse planes on the ground and break out ammunition.



Well stated. And even had American pilots found themselves somehow with fuelled and armed aircraft with pilots in the general vicinity of their planes, with clear airfields and enough time to marshal them aloft - Michael Bay movies and Death Star Trench scenes aside - what possible good raw pilots in P-36 and P-40s could have done against Japanese pilots in A6Ms remains to be seen. The results may have been surprising, though - the US did manage to fly 25 sorties in the event, and the USAF credits six pilots with 10 victories, six of them by Lieutenants Taylor and Welch, both in P-40s. Three of the other four kills, one apiece by four P-36 pilots, were unverified by the Japanese and there is speculation that they were actually lost to anti-aircraft fire. Then again, the number of friendly fire incidents would probably have increased as well - naval aircraft from U.S.S. _Enterprise_ were shot down later in the day, for example. But as I stated earlier, I have to agree with you that it is a red herring, and that I believe that this early warning would have made the attack costlier for the Japanese pilots by some degree but probably had little material effect on the outcome of the attack itself.


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