What are plausible decisions Imperial Japan could have made after Pearl Harbor to improve their performance in the war?

I always wondered, if the I-400's left all three floatplanes behind plus their supplies could the hanger accommodate a tank? A Panzer IV might be possible but a Panther would probably weigh too much and the Tiger I'm sure is too large. It could certainly carry jet engines and maybe a complete Me-163 (disassembled of course).

The I-13's had a hanger for 2 floatplanes, might be too small for a tank but it could carry a large amount of other material.
 
How about wising up a bit with the cryptography?

And for tech how about these:

Fire control improvements on carriers.

Anti-tank rockets, like a bazooka, ready by the time the defense phase starts to kick in.

Building more of the sturdier plane designs with more firepower but less range and agility. All around, it was definitely feasible to transition away from the zero and oscar by 44 and with extra breathing room, they should have been fielding stuff that could compete at least with hellcats. The zero just didn't have enough engine power to go much further. Also, they had to really work on their tactics and quit with the inclination toward one-on-one dogfighting. Having good radios would make coordinating easier. Their doctrine never emphasized survivability but that's exactly what they needed most.

Better oil refining for high octane fuel.

A more effective overland route through China for transport to bypass the subs for most of the route. Or did they already have this?

Get a lightish medium bomber with some damn self sealing tanks. It's worth the loss of range.
 
I always wondered, if the I-400's left all three floatplanes behind plus their supplies could the hanger accommodate a tank? A Panzer IV might be possible but a Panther would probably weigh too much and the Tiger I'm sure is too large. It could certainly carry jet engines and maybe a complete Me-163 (disassembled of course).

The I-13's had a hanger for 2 floatplanes, might be too small for a tank but it could carry a large amount of other material.
What good would a single tank do?
 
Delaying the war will not (odds are) delay the Atomic Bomb by all that much. The main meeting that truly started the ball rolling on the Manhattan Engineering District took place on Dec 18th 1941. It consists of a number of important folks and was already scheduled before December 7th so it was going to happen on December 18 no mater what.
The huge any expense push probably does not happen until things get more urgent. But the US was already starting to spend huge money on the military as everyone knew the war was coming. Case in point we were already looking at what became the B29 as well as the B36. We new it was going to happen and we (the US) was taking steps to prepare for it.
As for the Atomic Bomb. Much of the begining of that project (and any other for that matter) is getting managers and personal together. And finding out what you know and what you don’t know. Then starting to plan what you need to do. Non of that needs a HUGE commitment on day one.
So if you assume war with Germany comes a year later you are not losing a year. You are losing a few months. And in the end maybe not even that. As you will have a lot of things figured out so when the “panic” comes and the money is released it will be spent in the needed areas without as much time needed to figure out what to do with it.
Also the project will start when the US does not have the restrictions on resources so it won’t need the overri priority.
Please note I an mot saying it won’t be delayed, but that it won’t be delayed years unless you assume the US sits on its but. And being as the US spent much of 1940 and all of 1941 gearing up for the war it is hard to justify the idea that they would take a nap in 42.
That being said it could easily be argued that the bomb will not be delayed at all. As it is such a game changer that the US may just jump on it to have as a trump card. Heck you could argue that it may get sped up a bit. You probably are not getting the tech work done sooner so the First Bomb will odds are not get to the front sooner but you may see production go faster so that you see the 10th Bomb sooner.
As if the US does realize how importantthe atom bomb is and gives it the same priority and budget as otl you could be using that when In peace time. So you can get you hands on equipment meterials and skilled labor a LOT easier.
And you can hide things like Oak Ridge as part of one of the public works projects of the Alphabet Agencies.
So yes odds are it delays Bomb 1 a bit and we probably get bomb 10 on about original schedule.
But it has a pretty good chance of hardly being sloweed down and a minor chance to actually see Bomb 10 ahead of original schedul.
Hard to say but could be argued either way.
 
To be honest, I am rather skeptical that any of these German-Japanese tech transfers could do much, except be interesting historical curiosities.

Plus with Japan, had gotten very used to the fact that much of their shipping came on foreign hulls, and subconsciously did not want that loss, so no loss of Commerce, or plans to take over that trade were seriously looked at prewar.

Afaik, the IJN used submarines as if they were fleet units, ie, to attack other warships and conduct scouting for the main battle fleet, as part of their doctrine of "destroy enemy fleet, win the war". Comercial/logistic warfare was not part of this.

One curious aspect of Japanese submarine doctrine was that they actually didn't really test it that much in their naval maneuvers or training which is strange when you take into account how important they thought submarines were to their overall strategy. It was really only in the late-1930's that the IJN started to notice that it might not necessarily work as well as they had initially thought.

A more effective overland route through China for transport to bypass the subs for most of the route. Or did they already have this?

This was one of the aims of Ichi-Go in 1944, in addition to capturing American air bases in the region, but Japanese never found the route as useful as they had thought, partly due to a large amount of damage to the area's infrastructure. Maybe they could fix that if they had more time but that assumes Japanese were somehow succesful in an operation like that much earlier.
 
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McPherson

Banned
I always wondered, if the I-400's left all three floatplanes behind plus their supplies could the hanger accommodate a tank? A Panzer IV might be possible but a Panther would probably weigh too much and the Tiger I'm sure is too large. It could certainly carry jet engines and maybe a complete Me-163 (disassembled of course).

The I-13's had a hanger for 2 floatplanes, might be too small for a tank but it could carry a large amount of other material.

The PZKW IV tanks were heavy and awkward to shove into the aircraft shelters (which leaked), and would have affected the sub's roll moment. 30 tonnes concentrated in mass on a weak strong-back) on an overall 4,000 tonne submerged displacement sub (which had lousy roll moment underwater anyway) might not seem much but it would have been VERY problematic with trim control in a boat that handled like a drunk top-heavy swimming cow under the best circumstances. The I-400 was a really lousy boat.
 
Besides, the I-400 is too late in the war. We need something that could make the trip in late 42/early 43 at the most, loaded back with tons of blueprints and basic parts.
 

nbcman

Donor
Besides, the I-400 is too late in the war. We need something that could make the trip in late 42/early 43 at the most, loaded back with tons of blueprints and basic parts.
You mean like Commandante Capellini who sailed there successfully in mid 1943 or I-30 who sailed to France successfully but was lost returning in late 1942. See the wiki page for Monsun Gruppe for info about the cargo shipments.
 
What good would a single tank do?

For study.

The PZKW IV tanks were heavy and awkward to shove into the aircraft shelters (which leaked), and would have affected the sub's roll moment. 30 tonnes concentrated in mass on a weak strong-back) on an overall 4,000 tonne submerged displacement sub (which had lousy roll moment underwater anyway) might not seem much but it would have been VERY problematic with trim control in a boat that handled like a drunk top-heavy swimming cow under the best circumstances. The I-400 was a really lousy boat.

That's a good point.

Besides, the I-400 is too late in the war. We need something that could make the trip in late 42/early 43 at the most, loaded back with tons of blueprints and basic parts.

Another good point, the I-13 and I-14 weren't available until 1944 but the I-15 class with a hanger for one plane are available prewar. Large enough to carry a disassembled radar set or other bulky gear.

I agree that AT technology (Panzerfaust, Panzerschrek and HEAT rounds) need to be obtained ASAP as well as AA rocket and missile technology.
 
The PZKW IV tanks were heavy and awkward to shove into the aircraft shelters (which leaked), and would have affected the sub's roll moment. 30 tonnes concentrated in mass on a weak strong-back) on an overall 4,000 tonne submerged displacement sub (which had lousy roll moment underwater anyway) might not seem much but it would have been VERY problematic with trim control in a boat that handled like a drunk top-heavy swimming cow under the best circumstances. The I-400 was a really lousy boat.
The premise behind this transfer is extremely odd, Though my knowledge of Tanks is much more limited, it doesn't seem like later generation German Tank designs represented an idea that the Japanese needed German Technical assistance for, as opposed to Radar, Jet/Rocket propulsion and Nuclear Weapons. The other problem with this argument is that the lack of heavy tanks was far from the most pressing issue the Japanese army faced. Even without heavy tanks the Japanese army could still be effective in China in 1944. Against the US Tanks would have been little to no use in defending their Island bases against the Americans, while I don't think they where all that decisive in the New Guinea, Guadalcanal and Philippines campaigns.

Larger tanks didn't allow the Germans to defeat the Western Allies on the battle field, and for Japan the moment they could use these tanks against the Americans in the Philippines they have already failed by preventing the Americans from landing forces within the defensive perimeter.
 
If I might suggest something that someone else only even hinted at and everyone else ignored. Mayperhaps the Japanese figure out that their enemy is listening to every conversation of strategic importance they're having. That would help a lot.
 
If I might suggest something that someone else only even hinted at and everyone else ignored. Mayperhaps the Japanese figure out that their enemy is listening to every conversation of strategic importance they're having. That would help a lot.
I just mentioned that but, yeah, they had no excuse to keep ignoring it for so long. I mean, the Italians and Germans told them they were being read before Pearl harbor. The Japanese military of wwii had a level of hubris that almost defies belief.
 
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I just mentioned that but, yeah, they had no excuse to keep ignoring it for so long. I mean, the Italians and Germans told them they were being read before Pearl harbor. The Japanese military of wwii had a level of hubris that almost defies belief. It's like they were trying to lose. It's amazing they fought as effectively as they did.
You were that someone, apologies.
 

McPherson

Banned
The premise behind this transfer is extremely odd, Though my knowledge of Tanks is much more limited, it doesn't seem like later generation German Tank designs represented an idea that the Japanese needed German Technical assistance for, as opposed to Radar, Jet/Rocket propulsion and Nuclear Weapons. The other problem with this argument is that the lack of heavy tanks was far from the most pressing issue the Japanese army faced. Even without heavy tanks the Japanese army could still be effective in China in 1944. Against the US Tanks would have been little to no use in defending their Island bases against the Americans, while I don't think they where all that decisive in the New Guinea, Guadalcanal and Philippines campaigns.

Larger tanks didn't allow the Germans to defeat the Western Allies on the battle field, and for Japan the moment they could use these tanks against the Americans in the Philippines they have already failed by preventing the Americans from landing forces within the defensive perimeter.

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Kanto plains.

Source: tokyorailwaylabyrinth.blogspot.com

As pointed out, the American army was not that stupid.

The largest lowland in Japan is the Kanto Plain, situated on the Pacific coast of Honshu and bordering the northern shore of Tokyo Bay. It is only 5,800 square miles (15,000 sq km) in area. Other important lowlands are the Osaka Plain in west central Honshu, the Ishikari-Yufutsu Lowland in western Hokkaido, the Echigo or Niigata Plain in northwestern Honshu, the Nobi or Nagoya Plain in Honshu at the head of Ise Bay, and the Tsukushi Lowland in northern Kyushu. All of these are much smaller than the Kanto Plain.

Few of the depositional lowlands are actually flat-floored. Most of them display considerable slope; others, including the Kanto Plain, are marked by at least two levels of alluvial deposits, one old, one recent. The older alluvial materials are known as diluvium, and because of geologically recent uplift they rise as terraces anywhere from several feet to several hundred feet above the level of the newer alluvial deposits. Most are thoroughly dissected and in some cases resemble "badlands." Associated with them are soils, drainage, natural vegetation, land uses, and occupance patterns that further differentiate them from the lower areas of more recent alluvium. Thus the "plains" of coastal Japan are characterized by considerable surface differentiation. In fact, almost nowhere in Japan are there extensive level plains of the sort associated with horizontally bedded sedimentary formations, as in the Great Plains of the United States.

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Credit: Saved by Jose Capricorn on Pinterest. That is Italy.

Chi Nu

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Not everyone at IGHQ was completely insane or stupid, either. Just a tiny few of them.

About cryptology.

Comment: The Japanese thought they, hiding behind the wall of an ideograph based writing and the ideogram as opposed to phonetic systems of European root languages, had an extra firewall to guard their encryption. The Americans (not the British) blew through that firewall by understanding that mechanical printing and Japanese typewriters were extremely vulnerable to cracking and they went out of their way to figure out how the Japanese language would HAVE TO BE TYPEWRITTEN in code.

McP.
 

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You were that someone, apologies.
It's still a very easy and very important way to improve things so it's surprising we haven't touched on. What is more difficult is getting a code that is harder to break and having a better idea of how to tell when the next one is broken. Because any code is going to be broken fairly quick.

On that note, a bit better use of deception could have been of value. The Japanese lacked resources so they should have been working hard to improvise decoys and other tricks to make the attacking allies waste as many of their considerable resources as possible. The large number of very skilled small scale craftsmen for example, could have produced fake tanks, ships and planes like the British did.
 
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View attachment 522028

Kanto plains.

Source: tokyorailwaylabyrinth.blogspot.com

As pointed out, the American army was not that stupid.



64b2f24a04ce1aef125c916f6cda9478.jpg


Credit: Saved by Jose Capricorn on Pinterest. That is Italy.

Chi Nu

View attachment 522035
Not everyone at IGHQ was completely insane or stupid, either. Just a tiny few of them.

About cryptology.

Comment: The Japanese thought they, hiding behind the wall of an ideograph based writing and the ideogram as opposed to phonetic systems of European root languages, had an extra firewall to guard their encryption. The Americans (not the British) blew through that firewall by understanding that mechanical printing and Japanese typewriters were extremely vulnerable to cracking and they went out of their way to figure out how the Japanese language would HAVE TO BR TYPEWRITTEN in code.

McP.
How dumb did they think the Americans were? While not readily studied in most schools, there were plenty of people in the United States who could speak and read Japanese by then. Including but not limited to, Japanese-Americans. It's not like it was some obscure language. That should have been obvious to them. I think that the leadership may have had a very flawed understanding of the world outside of Japan.
 
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McPherson

Banned
How about wising up a bit with the cryptography?

1. See my comments about what they thought about ideographic (symbol/pictograph alphabet) languages.

And for tech how about these:

In order.

Fire control improvements on carriers.

2. If one means firefighting, then it varied from ship to ship. The IJN liked to automate their firefighting measures, because they thought their men would run away from fires. The exception was the Captain of the HIJMS Shōkaku. He believed in his men and did it the right way.

Anti-tank rockets, like a bazooka, ready by the time the defense phase starts to kick in.

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3. Source. Here. (1944)

Building more of the sturdier plane designs with more firepower but less range and agility. All around, it was definitely feasible to transition away from the zero and oscar by 44 and with extra breathing room, they should have been fielding stuff that could compete at least with hellcats. The zero just didn't have enough engine power to go much further. Also, they had to really work on their tactics and quit with the inclination toward one-on-one dogfighting. Having good radios would make coordinating easier. Their doctrine never emphasized survivability but that's exactly what they needed most.

1581120640636.png


Raiden. (Jack)

CREF "Tojo", "Frank", "George"

4. The problem is that they duplicated efforts and could not get the watts out of their aero-engines to make those things work.

Better oil refining for high octane fuel.

5. Need better aero engines more.

A more effective overland route through China for transport to bypass the subs for most of the route. Or did they already have this?

6. If they could do that thing, in the first place, then they would not be up to their eyeballs in American Marines.

Get a lightish medium bomber with some damn self sealing tanks. It's worth the loss of range.

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"Helen"

7. What killed it? Lack of watts from those engines.

How dumb did they think the Americans were? While not readily studied in most schools, there were plenty of people in the United States who could speak and read Japanese by then. Including but not limited to, Japanese-Americans. It's not like it was some obscure language. That should have been obvious to them. I think that the leadership may have had a very flawed understanding of the world outside of Japan.

8. Very dumb at the top (Imperial Japanese General Headquarters). And very flawed.... even Yamamoto failed to understand the similarities between Samurai and Cowboy cultures. It was going to be a war to the knife no matter what the Japanese did.
 

marathag

Banned
Though my knowledge of Tanks is much more limited, it doesn't seem like later generation German Tank designs represented an idea that the Japanese needed German Technical assistance for
IJA cut no metal for a tank that would be the equal of a 1940 Panzer Mk IV until 1943, years after they had experienced curbstompings from M3 Lees and M4 Shermans, and then the few built never left Japanese Home Islands.

The best was this the Type 4 Chi-To,
640px-Type_4_medium_tank_Chi-To_planned_production_model_01.jpg

two were finished in 1945, using a supercharged aircooled V-12 of 400hp, with a L56 75mm, comparable to the US 76mm, and 4 more unfinished chassis.
Mitsubishi was planning to build 20 a month

An M4 Sherman to IJA Armor was akin to the Panther to 75mm Shermans, the need to get with a couple hundred yards for a side shot, as the Frontal aspect was totally immune.
They needed Tanks, but they needed all that other stuff, as well
 
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