What does Japan do if War against USA/UK/DEI postponed to Spring 1942?

SaparotRob said:

I forgot if it was Lexington or Saratoga that successfully "bombed" Pearl Harbor.

Click to expand...

It was the Germans.

The Japanese can look at ww1 how America mobilization.

Don't need no crystal ball.

Admiral Beez said:

I have to wonder how the war would have gone had the Axis invested into foreign intel, including signals intelligence, and especially improved both their encryption and security/sops of diplomatic and military communication. A good intel network may have discovered the Ultra and Magic signals intelligence programs, forever changing the Battle of the Atlantic, Pearl Harbour, Midway, etc.

Some examples of where good foreign intel or even basic research into your opponent would be useful:
- Hitler is informed in early 1941 that the Soviet Union has >25,000 tanks, >18,000 aircraft, >117,000 artillery pieces, >5.7 million men.
- Japan gains an accurate appreciation of the US ability to scale up its military and of its cultural willingness to fight on no matter the losses.
- Mussolini now understands that he has no hope of beating the Allies in North Africa, and that his best course of action is to follow Spain's neutrality.

Click to expand...

The nice thing about threads like this is it makes me put some effort into becoming more informed about a topic before I post (usually). Regarding Japanese understanding of the US I came across this:

In 1940, Japanese planners had calculated that the industrial capacity of the United States was 74 times greater, and that it had 500 times more oil.

From this article: How (Almost) Everyone Failed to Prepare for Pearl Harbor

The Japanese took a risk. Earlier, in this thread I also stated that the Japanese failed to understand the US. I would like to change that to be the Japanese did understand the US, to a point. The Japanese underestimated American resolve and didn't plan an option other than hitting the enemy hard and hope they fold.

NevadaK said:

The Japanese underestimated American resolve and didn't plan an option other than hitting the enemy hard and hope they fold.

Click to expand...

But they didn't hit the US hard. Hitting them hard would include attacking the US mainland and Panama Canal, sabotaging/terror bombing major US factories, release poison gas, assassinating FDR. Basically cut the head off the snake.

It's an interesting post, Nevada K. The Japanese psyche was very different to the US one and the plan was an imaginative one for the time, equal to the likes of the attack on Copenhagen by Adm Nelson's fleet in 1801, (also Taranto a year earlier - you can thank the British for giving the Japanese the idea, dating back to aircraft carrier based torpedoplanes being sent to Japan, along with instructors in 1921) something that perhaps we forget in hindsight. Part of the impact that was hoped for by the Japanese was the psychological consequences, and because they believed they were spiritually and psychologically superior to Westerners, the impact should have been a major blow to the US collective psyche. That they underestimated US resolve is obvious, but it undercut their personal beliefs about the abilities of the average Western soldier and the impact a major blow might have.

Admiral Beez said:

I have to wonder how the war would have gone had the Axis invested into foreign intel, including signals intelligence, and especially improved both their encryption and security/sops of diplomatic and military communication. A good intel network may have discovered the Ultra and Magic signals intelligence programs, forever changing the Battle of the Atlantic, Pearl Harbour, Midway, etc.

Click to expand...

That's more a job of humint -- penetrating the decryption ops with spies -- than sigint, though the latter could be used. You're absolutely right that their foreign intel ops were deficient, except perhaps for the spy the Japanese placed in the Honolulu consulate, who from all accounts I've read provided good dope.

Admiral Beez said:

- Hitler is informed in early 1941 that the Soviet Union has >25,000 tanks, >18,000 aircraft, >117,000 artillery pieces, >5.7 million men.

Click to expand...

I seem to remember reading from John Erickson's The Road to Stalingrad that Gehlen at FHO had more accurate info regarding Soviet ToEs and ORBs, but was ignored by OKW as Hitler argued the whole "kick-in-the-door" thing. But it's been 20 years since I read the two-volume work and so the ole memory may be off.

Admiral Beez said:

- Japan gains an accurate appreciation of the US ability to scale up its military and of its cultural willingness to fight on no matter the losses.

Click to expand...

They had sent many officers to study in US universities as part of their military training. They should have schooled those officers thus detached to be observant of these matters. My reading indicates that a couple of IJN officers were (Yamamoto being the most famous), but that they were overruled by the Army clique ruling Japan at the time.

Admiral Beez said:

- Mussolini now understands that he has no hope of beating the Allies in North Africa, and that his best course of action is to follow Spain's neutrality.

Click to expand...

The Italians were reading American codes from our embassy in Cairo iirc. I don't remember if that was before or after America entered the war. They'd burgled the American Embassy and that's how they managed it.

Admiral Beez said:

But they didn't hit the US hard. Hitting them hard would include attacking the US mainland and Panama Canal, sabotaging/terror bombing major US factories, release poison gas, assassinating FDR. Basically cut the head off the snake.

Click to expand...

Admiral Beez,

I don't have the data at the ready, but I believe between Pearl Harbor and the attacks southward to the Philippines and Southeast Asia campaigns the Japanese had pretty much committed their entire offensive capabilities to knocking the United States out of the fight.

It's worth noting that none of the heads of states were assassinated during the war or gas warfare or terrorist attacks. It seems some things were still out of bounds.

Dimlee said:

It was the Germans.

Click to expand...

This is my all time favorite motivational speech. I was actually saving that line for an appropriate moment. Oh well.

NevadaK said:

Admiral Beez,

I don't have the data at the ready, but I believe between Pearl Harbor and the attacks southward to the Philippines and Southeast Asia campaigns the Japanese had pretty much committed their entire offensive capabilities to knocking the United States out of the fight.

It's worth noting that none of the heads of states were assassinated during the war or gas warfare or terrorist attacks. It seems some things were still out of bounds.

Click to expand...

The US had chemical weapons in readiness to use in Europe. An American ship carrying mustard gas was bombed in Bari harbor in December 1943. Nearly 100 died and over 600 injured by the chemicals released.

nuuumannn said:

That they underestimated US resolve is obvious, but it undercut their personal beliefs about the abilities of the average Western soldier and the impact a major blow might have.

Click to expand...

Imagine what they'd have assumed about US resolve if Japan had rolled over Malaya first, where >90% of the British forces surrendered. Did the IJA ever surrender in those numbers? After similarly rolling through FIC and DEI Japan will be thinking that any Western soldier would just need a poke and he'll fold.

French Indochina was under control of pro-axis Vichy leadership.

Greg Boeser said:

The US had chemical weapons in readiness to use in Europe. An American ship carrying mustard gas was bombed in Bari harbor in December 1943. Nearly 100 died and over 600 injured by the chemicals released.

Click to expand...

Right. But not even Hitler, who used insecticide on Jews, initiated gas warfare. What was at Bari was in readiness in case US troops were gassed; it was not planned for use in any other circumstance.

Greg Boeser said:

French Indochina was under control of pro-axis Vichy leadership.

Click to expand...

Japan still had to fight their way in. Japanese invasion of French Indochina - Wikipedia

Looks like they chose to.

Thumpalumpacus said:

That's more a job of humint -- penetrating the decryption ops with spies -- than sigint, though the latter could be used. You're absolutely right that their foreign intel ops were deficient, except perhaps for the spy the Japanese placed in the Honolulu consulate, who from all accounts I've read provided good dope.


I seem to remember reading from John Erickson's The Road to Stalingrad that Gehlen at FHO had more accurate info regarding Soviet ToEs and ORBs, but was ignored by OKW as Hitler argued the whole "kick-in-the-door" thing. But it's been 20 years since I read the two-volume work and so the ole memory may be off.


They had sent many officers to study in US universities as part of their military training. They should have schooled those officers thus detached to be observant of these matters. My reading indicates that a couple of IJN officers were (Yamamoto being the most famous), but that they were overruled by the Army clique ruling Japan at the time.



The Italians were reading American codes from our embassy in Cairo iirc. I don't remember if that was before or after America entered the war. They'd burgled the American Embassy and that's how they managed it.

Click to expand...

Italian reading of US Embassy codes lasted from Sept 1941 to June 1942

The Germans did invest in signals intelligence and code breaking from pre-war. And they had their successes against British, US and Soviet codes.

And like Britain they had their successes in capturing codes books. One notable case was when the raider Atlantis captured the SS Automedon in the Indian Ocean in Nov 1940. A whole host of useful papers, including Admiralty code books, were discovered in her strongroom. These were immediately taken to the German Embassy in Tokyo where they arrived before Christmas and much was then shared with the Japanese. Why weren't they dumped overboard? A very unfortunate set of circumstances including the responsible officers being killed by German shelling, and a request from a Mrs Ferguson to have her tea set rescued!

And the Japanese too had their intelligence & code breaking successes both before and during WW2. That included both US and British diplomatic codes in 1940/41. It is just that we hear little about them as so much was destroyed at the end of WW2 or disappeared into classified US archives.

Admiral Beez said:

But they didn't hit the US hard. Hitting them hard would include attacking the US mainland and Panama Canal, sabotaging/terror bombing major US factories, release poison gas, assassinating FDR. Basically cut the head off the snake.

Click to expand...

While there were minor operations against the mainland USA either carried out or proposed, geography was against the Japanese. With the exception of part of the pre-war aircraft industry, most US war production was based on the eastern part of the country, from the east coast to the Great Lakes. It is over 6,000 miles from Tokyo to Chicago. Over 8,000 to Panama. When, from 1940, new plants were needed, they were being created well away from the coasts.

But we do have examples of the Japanese striking or attempting to strike the mainland USA and shipping in West Coast waters-

Japanese submarine operations in 1941/42 including shelling by I-17 & I-25

These events, occurring in the months following PH certainly added to US hysteria about a possible Japanese invasion, leading to "The Battle of Los Angeles"

Fu-Go balloon bombs in 1944/45

Plans to bomb the Panama Canal in 1945. But when conceived in 1942 it meant designing and building a new aircraft and the submarines to carry them.

Ultimately none of these activities turned out to be more than pin pricks but they do demonstrate Japanese intent.

While there were many plans by countries to assassinate other countries leaders during the war, I can't think of one that was carried out. Always seems more of a Cold War activity. Besides all the issues of access and high levels of security to be overcome, there is a much more difficult question. Who will succeed them? Sometimes it is a case of better the enemy you know, and the hope that, if incompetent, he will continue to make mistakes!

As for the use of chemical weapons in WW2, every major combatant nation had them, tested them and moved them around in their rear areas, and had plans to use them if someone else did. Britain had extensive plans to use gas in the event of a German invasion. The Germans invented nerve gases to sit alongside more "conventional" chemical weapons, but never used them, allegedly because of Hitler's experiences in WW1. The Bari incident was the downside of what could happen due to the secrecy involved in their movement.

But in 1945 with Operation Olympic coming up the US was moving chemical weapon stocks from rear areas in Australia to the Philippines in case they were needed. The Japanese disclosed post war that if the US had used them first then they would retaliate in kind. In a backs to the wall invasion, who knows, they might have adopted the British approach.

Biological weapons were used by the Japanese in China. Churchill wanted to use anthrax against Germany but cooler heads prevailed. The US contemplated using biological weapons against Japanese crops, but then realised that if it invaded in the aftermath it would have to feed the Japanese population as well as its own troops so putting a great strain on logistics.

The problem with both chemical and biological warfare is that, unless you are using it in a China type situation with a non technologically advanced country, the risk is that you will reap what you sow. But against the industrial might of the USA at least tenfold.

EwenS said:

While there were minor operations against the mainland USA either carried out or proposed, geography was against the Japanese.

Click to expand...

Good points. And demonstrative that Japan really couldn't do anything to harm the USA. But they could try to terrorize the place? As you say the distances are huge and there are few targets on the west coast, but how about a Scarborough Raid? Sail a battlecruiser force to Seattle, bombard the place. It's about 15,000 km round trip, well within the 19,000 km (@ 14 knots) range of the Kongo class.

Had the USA decided not to redeploy its battlefleet and carriers from the US west coast to Hawaii what would the Japanese have targeted in Dec 1941?

Coastal batteries.

Try googling a map of Seattle.

Shortround6 said:

Coastal batteries.

Click to expand...

Will they be more prepared and effective than the radar operators and air defence coordinators at Pearl? I expect anyone assigned to WA's coasts shore batteries never expected to ever fire a shot in anger, with perhaps limited training or live ammunition practice, and will likely be playing cards or otherwise larking about.

But I am really just reaching for anything now, so I mostly jest. Clearly there's nothing Japan can do to strategically hinder the USA. It was a dumb move on their part. The smarter move was to find a face saving way out of China so that the sanctions are canceled and Japan can continue its military build-up and wait and see whose side they should join in the expanding world war.

One of the reasons shore batteries did not respond to the shelling from the sub, was that during practice the shore batteries' firing broke windows in town as well as terrifying citizens. Return fire for sub deck guns was not going to happen.