What does Japan do if Pearl Harbor prepared in advance?

What does Japan do if Haiwaii and Pearl Harbour are overtly prepared in advance? I mean by summer 1941 there are effective radar chain systems and demonstrated effective fighter director SOPs, an effective and large fighter force conducting, five fleet carriers on station at PH (Saratoga, Lexington, Hornet, Yorktown and Enterprise). I don't want to debate the specifics of the above, but am instead seeking that level of US strength that demonstrates to the Japanese that a preemptive strike will not catch American unawares.

If we can achieve the above, how does Japanese alter its war plan?
I wonder if this could possibly be worse for the usn.

What I'm thinking is that the pearl harbour attack was historically somewhat handicapped by the fact the majority of strike planes went for airbases (for understandable reasons).

If Japan sees a fortified Pearl Harbour maybe they spend a few months trying to figure out a night attack.

If they do go for a night attack with twice as many planes over the harbour they may do better than historically.

Also with a change of date (for a full moon) maybe the carriers are in port.
 
maybe they spend a few months trying to figure out a night attack.
I see two problems. One, IJN (AFAIK) didn't operate a/c from CVs at night, so you need to change that. Two, Japan has a fairly narrow window to work in: after the oil embargo, supplies are increasingly limited; plus, U.S. fleet building is starting to reach service. If Japan waits too much longer, the attack will be futile. (Well, okay, more futile...:openedeyewink:)
 
I see two problems. One, IJN (AFAIK) didn't operate a/c from CVs at night, so you need to change that. Two, Japan has a fairly narrow window to work in: after the oil embargo, supplies are increasingly limited; plus, U.S. fleet building is starting to reach service. If Japan waits too much longer, the attack will be futile. (Well, okay, more futile...:openedeyewink:)
The op suggests US fortifications in summer 1941. Regarding flying off at night well necessity is the mother of invention. Maybe they will see base attacks as different from sea attacks as bases are somewhat easier to attack at night than ships at Sea (bases don't move).
 
The op suggests US fortifications in summer 1941.
Noted. I'm saying, Japan really can't wait much past OTL's date, or it's going to be for nothing, even from a 1942 perspective.
Regarding flying off at night well necessity is the mother of invention. Maybe they will see base attacks as different from sea attacks as bases are somewhat easier to attack at night than ships at Sea (bases don't move).
Attacking is less an issue for me than recovery...
 
A better prepared PH has posited a decent radar coverage. Therefore a night attack won't be a surprise. Sure in 1941/1942 the night fighting capabilities of PH won't be so much, but with a blackout over PH, AAA fire, exactly how effective will the KB's attack be. Unlike Taranto I can't see the defense at PH allowing the Japanese to flutter about dropping flares to guide torpedo bombers in. The runs in PH were difficult enough in daylight. Hitting the airfields will be difficult, and strafing runs won't happen. Of course a "prepared" PH has at least a fair number of aircraft in sandbag revetments. The net result, let's assume done Saturday night/Sunday morning 12/6-7, will be much less effective than OTL. Losses will be just as bad if not worse, with the inevitable losses from an attempt at a night landing or at best early dawn. Except for the carriers not being in port, what the IJN achieved was all that coukd be expected and more with 2 strikes.
 
If the premise of the OP is taken as our departure, I see 3 different options

1. Modify the attack plan, attack at first light and prepare to fight their way in (high risk, see "Battle at Dawn" for possible results of this. Likely result: probable heavy damage to the fleet (battleships) but at an excessive cost (potentially 1/3 to 1/2 of the attack force)

2. The Imperial Navy tells Yamamoto 'no' as the risks are too high. The carriers instead support the Southern Operation and the Navy goes with its original pre war plan which consists of using attrition tactics with aircraft and submarines to weaken the USN before defeating it in Decisive Battle. As the USN was willing to wait until 1943 to even start the main part of the drive based on Plan Orange (needs time for the support ships and combat ships being built under the 2 Ocean Navy plan) this likely ends poorly for Japan anyway, but potentially could be pretty costly for the USN too.

3. Variation of 2, but after seizing Rabual and the Solomons drive into the South Pacific (Fiji/New Caledonia/Samoa) earlier, say February/ March 1942) instead of May - August 1942 (the OTL plan) while the US is still trying to secure that line of communications. This requires some pretty substantial planning and strains tanker/oiler resources and definitely more troops from the Army earlier. Has the advantage of putting heavy pressure on the Americans and possibly drawing the USN into battle far from its major base at Pearl Harbor (instead of say Midway).
 
If the premise of the OP is taken as our departure, I see 3 different options

1. Modify the attack plan, attack at first light and prepare to fight their way in (high risk, see "Battle at Dawn" for possible results of this. Likely result: probable heavy damage to the fleet (battleships) but at an excessive cost (potentially 1/3 to 1/2 of the attack force)

2. The Imperial Navy tells Yamamoto 'no' as the risks are too high. The carriers instead support the Southern Operation and the Navy goes with its original pre war plan which consists of using attrition tactics with aircraft and submarines to weaken the USN before defeating it in Decisive Battle. As the USN was willing to wait until 1943 to even start the main part of the drive based on Plan Orange (needs time for the support ships and combat ships being built under the 2 Ocean Navy plan) this likely ends poorly for Japan anyway, but potentially could be pretty costly for the USN too.

3. Variation of 2, but after seizing Rabual and the Solomons drive into the South Pacific (Fiji/New Caledonia/Samoa) earlier, say February/ March 1942) instead of May - August 1942 (the OTL plan) while the US is still trying to secure that line of communications. This requires some pretty substantial planning and strains tanker/oiler resources and definitely more troops from the Army earlier. Has the advantage of putting heavy pressure on the Americans and possibly drawing the USN into battle far from its major base at Pearl Harbor (instead of say Midway).
While I think a variation on Option 2, Nimitz using his CVs to raid the edges of Japan's "barrier" defense while his (English's) subs (all of the Asiatic & Pacific Fleet boats, based out of Pearl) choke Japan's SLOCs. Politically, I think it's unviable, given MacArthur (not to mention Oz, which could be handed over to the Brits to deal with--if you're prepared to have MacArthur in Hawai'i.:eek: {I'd sooner have the plague in Hawai'i.:openedeyewink:})

So, what we get is SWPA with all the marbles, more/less. Now, this might leave Nimitz free to use English's subs on SLOCs, without risk of fratricide from SWPA...except, one of the best patrol areas (Luzon Strait, between Luzon & Formosa) would likely be off-limits for that reason... Still, if it puts the OTL Oz boats in Hawai'i & more boats off Japan & Korea, Japan loses faster--even while MacArthur takes his sweet time to go from New Guinea to Celebes to Tawi Tawi to...oh, wait, the Sovs have declared war: the war is over...:openedeyewink: ("I shall run for President"...)

Oh, FYI: IMO, the war would end sooner than OTL in this scenario--but not a lot.

Edit: I should add, it probably precludes Allied landings at Anzio, at the very least, & maybe Anvil, too--unless the Allies don't reduce the priority on building LC (which was done OTL after the decision to push Neptune back to '44 was taken); given SWPA demand for LC, it's likely the priority is as high as OTL, or higher--& fewer CVEs/CVLs are built, instead (which will not be a bad thing in the long run).
 
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IIRC the whole Barrier idea was thrown out the window with the carrier strike on Rabul by the Lexington. Big strongpoints like that were meant to be able to ward off and deal with any US air attack, but the IJN lost 23 aircraft to no damage to the USN ships and it was seen as a small disaster. The Salamaua-Lae raid also showed how porus the barrier was.
 
If torpedo nets had been installed I see fewer BB losses. The combination of non-continual radar coverage and fighters being protected from sabotage (thus not armed or fueled) was just inviting disaster.

Japan PLANNED on losing 2-3 carriers in the attack, the fact Kido Butai wasn't even attacked was a shock. If they had been then Hiryu and Soryu might not have been available to support the second Wake Island attack, we might have been able to get the civilians out and reinforce the Marines there...
 
If the premise of the OP is taken as our departure, I see 3 different options

1. Modify the attack plan, attack at first light and prepare to fight their way in (high risk, see "Battle at Dawn" for possible results of this. Likely result: probable heavy damage to the fleet (battleships) but at an excessive cost (potentially 1/3 to 1/2 of the attack force)

What altitude did the level bombing attacks occur at, and what altitude di any dive bombers at PH start from? How long would it take the P35 & P40s to reach that altitude?

2. The Imperial Navy tells Yamamoto 'no' as the risks are too high. The carriers instead support the Southern Operation and the Navy goes with its original pre war plan which consists of using attrition tactics with aircraft and submarines to weaken the USN before defeating it in Decisive Battle. As the USN was willing to wait until 1943 to even start the main part of the drive based on Plan Orange (needs time for the support ships and combat ships being built under the 2 Ocean Navy plan) this likely ends poorly for Japan anyway, but potentially could be pretty costly for the USN too.

Not any worse than the naval battles from May - November 1942. Both sides effectively lost their carrier fleets, and had large losses in cruisers/destroyers. A few BB went out of action as well.

3. Variation of 2, but after seizing Rabual and the Solomons drive into the South Pacific (Fiji/New Caledonia/Samoa) earlier, say February/ March 1942) instead of May - August 1942 (the OTL plan) while the US is still trying to secure that line of communications. This requires some pretty substantial planning and strains tanker/oiler resources and definitely more troops from the Army earlier. Has the advantage of putting heavy pressure on the Americans and possibly drawing the USN into battle far from its major base at Pearl Harbor (instead of say Midway).

Early on the USN made a decision to establish its S Pac base at Wellington. While not perfect it did serve as the main base from the spring of 1942 through 1943. Fuel storage, warehouses, machine shops, docks were adequate, and were improved fairly quickly during 1942. The big failing was lack of a large enough dry dock. In retrospect we can see Wellignton was out of reach of anything more than a IJN raid. Strictly speaking the Fiji, Samoa region was as well, but that might not have prevented a try.
 
While I think a variation on Option 2, Nimitz using his CVs to raid the edges of Japan's "barrier" defense while his (English's) subs (all of the Asiatic & Pacific Fleet boats, based out of Pearl) choke Japan's SLOCs. Politically, I think it's unviable, given MacArthur (not to mention Oz, which could be handed over to the Brits to deal with--if you're prepared to have MacArthur in Hawai'i.:eek: {I'd sooner have the plague in Hawai'i.:openedeyewink:})

Nonsense, you send him off to a very important duty station in Alaska dealing with the minor Japanese invasion there, and then simply instruct your secretary to not forward any calls to you.
 
What altitude did the level bombing attacks occur at, and what altitude di any dive bombers at PH start from? How long would it take the P35 & P40s to reach that altitude?



Not any worse than the naval battles from May - November 1942. Both sides effectively lost their carrier fleets, and had large losses in cruisers/destroyers. A few BB went out of action as well.



Early on the USN made a decision to establish its S Pac base at Wellington. While not perfect it did serve as the main base from the spring of 1942 through 1943. Fuel storage, warehouses, machine shops, docks were adequate, and were improved fairly quickly during 1942. The big failing was lack of a large enough dry dock. In retrospect we can see Wellignton was out of reach of anything more than a IJN raid. Strictly speaking the Fiji, Samoa region was as well, but that might not have prevented a try.

according to my research for "Battle at Dawn" the interceptors could (the Japanese were flying between 8-10,000 feet)

Yeah, the Japanese would likely have suffered the same levels of defeat particularly as the USN can afford to trade ships but the Japanese cannot. I don't think any of the choices are going to work out in Japanese victory, but I think the Japanese would think differently.
 
Agreed, galveston bay, Japan won't win. At best she does the same at Pearl Harbor and loses the war in 1945, or she does a lot worse and the war ends earlier.
 
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The Salamaua-Lae raid also showed how porus the barrier was.
At the risk of being monotonous, I'd suggest subs sinking merchantmen did that. If IJN couldn't protect its own SLOCs (& it couldn't...), the garrisons making up its "barrier" defense would end up ineffectual even if the USN never attacked them. (Cf island hopping...)
Nonsense, you send him off to a very important duty station in Alaska dealing with the minor Japanese invasion there, and then simply instruct your secretary to not forward any calls to you.
So where were you in 1942? The U.S. could've used somebody so smart.:openedeyewink::cool:
 
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So where were you in 1942? The U.S. could've used somebody so smart.:openedeyewink::cool:

Well honestly, I would also have suggested that he has a service pistol and should use it before capture in lieu of risking a valuable submarine to evacuate his failure of an ass. But penguin counting in the Aleutian islands is a vital duty for the general who managed to lose his command that badly!
 
Nonsense, you send him off to a very important duty station in Alaska dealing with the minor Japanese invasion there, and then simply instruct your secretary to not forward any calls to you.
I know that me being a MacArthur fan put something on a very short list when it comes to that. However is initial handling of the war in the Pacific was not real good, but Pacific was the bastard child of the war had time, he more than redeemed himself to the rest of the war he made Japan a democracy and his handling of Japan probably stopped a gorilla war.
The Inchon Landing is one best example of this ability as a general. The fact that the failed businessman from Missouri decided that he could run the war better. Yes that he is the commander-in-chief is true that he was another link in the worsening, it's a few examples Obama being one did not, decided to run the war of the way he wanted to not the way military did. While I agree that is their right Carter's fuck up of the hostage rescue shows exactly why you have experts below you, Obama is one example of giving the military a task and not making major changes to it, let the experts come up with a plan for the president to review and approve. Regardless of Mac Arthur's being way to open about what he thought of Truman we would not be having the Korea problem today had they let him fight the war. Korea gave Japan the Big boost in the economy by having some of the material for the war made in Japan he gave them a
boost in their economy. And you can thank Truman and Eisenhower that Korea is the problem it is today with an arm assist instead of an actual win. I consider Patton one of the great generals also which is just as disliked on the board. Both of these officers made mistakes has did all generals and the military in general but they also both okay very good results. From The Inchon Landing to the Battle of the Bulge, Patton was the only General who said he could get troops to the Battle of the Bulge all the other General said it was impossible including one of the worse generals lMHO Montgomery.
 
MacArthur ...more than redeemed himself to the rest of the war
No, he really didn't. His mania for retaking the P.I. diverted forces to SWPA to no gain (not least the "guerrilla submarine" missions), kept CVs away from the fighting for crucial months (which lengthened the war about 6mo), & contributed to making it harder to conquer Iwo Jima & Okinawa (which between them lengthened the war at least another two months).
he made Japan a democracy and his handling of Japan probably stopped a gorilla war
Dubious at best.
Carter's fuck up of the hostage rescue
You are so wrong, it's staggering. That was a clusterfuck right out of the Pentagon: forces unwilling to be denied access to a high-profile mission leading to use of unqualified aircrews in a rush job that was pretty well buggered before it launched.
we would not be having the Korea problem today had they let him fight the war.
We are having a Korea problem now, & have been for 50yr, precisely because MacArthur did fight the war his way: he advanced to the Yalu, to no purpose, & the PRC reacted as you might expect. (Imagine, if you will, a PRC army advancing northward from Belize to the Rio Grande...)
penguin counting in the Aleutian islands
I'd agree--except you're in the wrong hemisphere for it.:eek:

Do the Brits need help defending the Falklands from Nazi-leaning Argentina?:openedeyewink:
 
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