I’m guessing changing codes is a really big deal and a super hassle because I cannot imagine sticking to one for most of a war when you know your enemy is doing their level best to break your codes.
…aaand that brings us back to Midway. The IJN code, known by the US as JN25, had regular updates. The version in use, JN25b, had been distributed right before Pearl Harbor in December 1941. It was to have been replaced April 1st, but due to difficulties in distributing the new update across their conquests, was delayed to May 1st and then to June 1st.
The US had succeeded in cracking large parts of the code, leading to the Coral Sea and Midway actions. While the battle of Midway was still ongoing, the Chicago Tribune filed a story “Navy Had Word of Jap Plan to Strike at Sea.” The story called out, correctly, the ships in the Japanese force.
There was no mention of codebreaking or communication intelligence, but the USN feared the Japanese would realize the details would have come from reading their coded messages.
The Justice Department convened a grand jury to investigate whether the Tribune had violated the Espionage Act, and though none of the press coverage of the case mentioned codes, it was clear that a trial would have called attention to something that no one wanted to discuss openly for fear of alerting the Japanese.
After it was all over, a congressman made a speech on the floor of the House castigating the Tribune for misuse of freedom of the press, and said “that somehow our Navy had secured and broken the secret code of the Japanese Navy.” That the Tribune had not published that seems to have slipped his mind. Navy codebreakers were beside themselves, but it seems to have passed by the Japanese. They did note, though, that codebreaking started to get harder from then on.
I know you know this but …
It’s important to distinguish between coding systems and a specific instance of a code in that system.
Changing codes involves handing out new materials to all participants. Which in the 1940s may have been paper books, specially machined cams, things like that. Difficult for an inherently dispersed force like a Navy.
Changing systems involves building, integrating, & deploying new hardware & operator training. Plus new coding material to match. A much more daunting problem.
From the code-breaker’s POV, each new set of coding materials represents a fresh challenge in a fairly well-understood problem space. Each new coding system represents a fresh challenge in a completely mysterious problem space.
The former might be hard, but the latter is super-hard.
Even today, every code and coding system is best understood as a wasting asset. The longer / more volume it’s used, the less secure it becomes.
Now that I have a little time, I wanted to go back and respond to a few of the earlier points.
One of the problems with strategy games and alt-hist scenarios is that they inevitably discount the importance of experience and accumulated knowledge in the creation of strategies and the ability to carry them through. What was possible to do by the end of the war was impossible at the beginning because the military didn’t have the necessary core knowledge.
The IJN’s Combined Fleet was the most powerful fleet in the world until it was decimated at Midway because no other country had thought of bring together a large group of carriers and having them work together. The Japanese were able to cause such destruction at Pearl Harbor because they had a fleet of carriers which were able to use squadrons of three different type of aircraft which completely different flying speeds and characteristics, from six separate platforms, and made a unified attack. This was something the USN wasn’t able to really do until much later in the war. The US did learn and by the end of the war, the US had far larger task forces than the First Fleet and was able to overwhelm the local defenses.
A major failure of all parties in the war was to suppose that the enemy would follow your own doctrine, combined with the lack of imagination of military intelligence to conceive of alternative doctrines which the enemy may have and then fail to anticipate possible attacks.
Prior to December 7, 1941, it was well-know that Japan had a record of starting wars by sneak attacks. A United States war game had the Japanese attack Pearl Harbor, from the north, IIRC on a Sunday. Where the US failed was to take into consideration that the Japanese had far more advanced carrier doctrines than the US. Local leadership believed that Japan would likely only attack with one or two carriers, because that’s what the US would have done.
Interestingly enough, the attack on Pearl Harbor resulted in the USN having to fundamentally change its core believe in the supremacy of the battleship, while the architects of the raid failed to understand the true significance of what they had done and didn’t alter their beliefs until much later.
The 7th Cruiser Division with four heavy cruisers, was only 45 minutes away from position to bombard Midway when they received the order to withdraw. It happened that were was a US sub in the area, and as they turned back they spotted the sub, taking evasive maneuvers, resulting in two cruisers ( Mikuma and Mogami) colliding, leading to the eventual sinking of Mikuma. As has been noted, any shelling would not have likely degraded the defense of the island.
I’ve already responded to a similar question, but thought that it would be good to further clarify.
It doesn’t seem to be that clear cut. There really wasn’t a great strategy to begin with, in that it was just an assumption by the various parties in the Japanese military and government that somehow the US would give up after they were soundly defeated in the early months. Perhaps the US would continue, but they US wouldn’t devote their entire might to the fight. That assumption was necessary for them because it was obvious to most of them that America was too strong.
After six months of nonstop Japanese victories, which still didn’t result in an US capitulation, there was further debate on the next steps. This is were a possible invasion of Australia was discussed, as was the cutting of the line of communication between the US and Australia. The same willful ignorance of the overwhelming odds against them that lead to the start of the war also lead Yamamoto and the Combined Fleet planners to continue to want to take territory in Central Pacific, first with Midway and then Hawaii. This is despite its easily proven fatal flaws; the overwhelming forces on Hawaii and the logistics, among others.
Things as gone too well for six months and they didn’t have any really great strategies or ideas of how to get the US to give up. In early April, Yamamoto had an assumption that the US was already beat and it would take something on the level of an invasion of Midway to draw them out into the fight. The Doolittle raid and Battle of Coral Sea didn’t force him to rethink this assumption.
Great post. Thank you.
I know you’ve lived in Japan and may still. I’m curious whether your username was chosen because of where you live(d), or because of your expertise on WWII in the Pacific which famously came to an end in, yes, Tokyo Bay?
To answer the question, first I want to refer back to a post by John DiFool
and following that example, I, too would like to quote from Shattered Sword
There was nothing that they could have done because they didn’t understand modern warfare.
The problem with relying on a decisive battle is that it requires the cooperation of the other party, and the US simply wasn’t going to play ball with them. The US could pick and choose which battles to fight and which to retreat from, which they only needed to in the early days.
Ironically, Yamamoto’s planned attack on Pearl Harbor made the decisive battle less likely rather than more likely as the decisive battle relied on battleships attacking battleships. If you sink and put a bunch of the enemy’s BB out of action they aren’t going to steam out to fight you. Again, no one really debated this.
I’ve been rereading Eri Hotta’s 1941 and reading again how they had chance after chance for individuals to have spoken up and stopped the path to war. They needed to have not declared war. Once it was declared, their fate was out of their hands.
That led to a major Japanese error. A message was encoded using the new code and sent out to ships at sea. And then, because they knew that not all ships had received the new codes yet, they recoded the same message in the old code and sent it a second time. This is something they teach you about in code school in a class titled “Don’t Do This 101”.
I agree. Japan spent the entire war trying to push the war into the kind of war they could win. But they had no way to compel the United States to fight that kind of war.
This went all the way back to the start of the war. People have noted that the Japanese made a mistake during the Pearl Harbor attack by not targeting the oil tanks and repair docks.
But the reality is Japan couldn’t target those facilities. Attacking logistic facilities would have been an acknowledgment that logistics mattered; that the war was going to be drawn out and things like the ability to supply and rebuild ships would be a factor. And if Japan acknowledged those things were going to be a factor in the outcome of the war, they would have to admit they couldn’t win the war.
So Japan dismissed logistics from their plans. They told themselves that the war would only last a few months before the United States agreed to terms so things like who had a secure supply of oil and who could repair ships and put them back into battle wouldn’t matter. The plans for the Pearl Harbor attack were drawn up on the assumption that it was going to a short war and targets should be chosen on the basis of what would give Japan the most short term advantage.
This was a problem for Germany also - early on Germany had a lot of luck and really good operational doctrine, so managed a lot of rapid and total victories. But they never had a plan to deal with the UK, they just assumed the UK would give up after France fell, maybe with some bombing. When they invaded the USSR, they had no actual plan to force a surrender, they just picked an arbitrary line on the map (that would be difficult to reach with zero opposition) and said ‘we’ll keep conquering until they get here and kill their armies on the way, then they’ll surrender’. When they had destroyed more armies than their intelligence said the USSR possessed before the war and were still facing larger armies in the field than they expected to even see in the first place and were nowhere near the Archangel-Astrakahn line they were supposed to reach, they still continued to think that they were just inches from victory.
That took/takes some powerful weed!
Of some interest this video was recently posted:
Not only did they make their perimeter harder to defend, it made logistics that much worse. Each kilometer further they expanded added two kilometers to the already overly strained shortage of ships. As there was nothing of value in most of these distant islands, the return trip was wasted.
Among all the combatants of the war, only Japan depended on ocean shipping for a major component of domestic transportation of goods. Hokkaido was a major source of rice, for example, and Japan depended on sugar from sugarcane grown in Taiwan and Okinawa. Sugar was a highly valuable commodity not only for diet but also for its use in industrial alcohol and munition.
Part of the war planning involved wishful thinking about the inability of the US to sink Japanese merchant marine ships and overly optimistic estimates of Japanese ability to offset the losses. At the
At the outbreak of the war, Japan lacked adequate shipping capacity for it’s civilian needs. It’s been estimated that Japan required 10 million tons of shipping but only had six million tons. The remaining four million tons was carried by foreign-flagged ships. Part of this loss was covered by capture of Allied merchant marine ships after the commencement of the war; (I seem to recall about 50% of that, but I’m unable to find a cite now), but that was insufficient for the Japanese economy, population and war industries. Additionally, the Army requisitioned civilian ships for its needs, but these came directly from the already inadequate Japanese merchant marine.
The argument has been made in this thread concerning the supposed brilliance of Yamamoto’s strategical abilities, but his grand plan involved ignoring the physical realities of insufficient ships. Hawaii was not self sufficient in food, and those requirements also were beyond Japanese logistical limits.
After a total of 22-odd years I’m left Japan and now living in a small city in Taiwan. Japanese history has fascinated me ever since 1981, when I first lived there.
I spent most of my time in the Tokyo / Yokohama area and one of my favorite places is the Daiba Park in the bay, the remnants of No. 3 Battery, off the Shinagawa coastline that was one of the hastily created forts after the Perry sailed. 台場 means battery. For a while I lived on a bluff overlooking the Yokohama port, and not surprisingly, that area still retains 台 in its name as it was also made into a fort.
Unfortunately for the Japanese batteries, would not match the range of Western naval ships, and would have suffered the same fate as the forts in the 1863 Bombardment of Kagoshima.
WWII also was of particular interest as I lived in Nagasaki a few kilometers from the epicenter, and personally knew survivors. For a while, my (now ex-) wife and I lived with her family, both of whom had survived American firebombing in Tokyo. The mother lived in the area destroyed in the first raid and the father in another part of town was in a later raid. I also had had a girlfriend whose father, a former Zero pilot, survived the Great Marianas Turkey Shoot and was slated to joining the kamikaze ranks in the defense of the homeland. Japan doesn’t spend a lot of time rehashing the war but I did see some interesting NHK documentaries from the Japanese perspective.
Fascinating. Thank you for sharing that bit of personal history.
It’s always interesting to see well-preserved period fortifications. And to realize what a small & personal scale battles were fought on back in whatever day. The irrelevance of fixed fortifications in the modern world means preserving military history for the long term is that much harder now; a building or yard full of machines or a rusty hulk tied to a pier doesn’t have the same emotional immediacy nor staying power.
Getting to know veterans and survivors of the other side is a rare and special experience. It’s a curative for buying one’s own nation’s triumphalist narrative lock stock and barrel. Absent the Civil War, the US hasn’t had significant enemy action on its own soil, and hence significant civilian casualties, occupying forces’ abuse or atrocities, etc., since the end of the Revolutionary War. That good fortune breeds a certain false sense of invincibility. As the Japaneses learned to their detriment starting in about 1943.
Sorry to hear the wife is ex-. That’s always simultaneously a tragedy and a relief. English ought to have a word for that.
Catharsis comes close, with a preceding tragedy being heavily implied.
Incidentally, this is a big reason why Franco never came close to entering the war. Spain was like Japan in that the country depended heavily on shipping around the coast and oceanic imports for her food supply, and had Spain joined the Axis the Allies would have had no problem expanding the blockade to Spain and interdicting most coastal shipping. Franco was a lot more aware of reality and willing to accede to practical demands than leaders in Germany or Japan, and while he was willing to string Hitler and Mussolini along pretty clearly had no desire to do more than profit off of them and secure his own regime.
This also had a lot to do with Admiral Canaris, head of the Abwehr, and a friend of Franco, who told Franco how to handle Hitler and that Hitler was not to be trusted.
Hitler went into negotiations with Franco, and came out with a headache, confused, and nothing that he really wanted.
The problem with Kantai Kessen, and Pearl Harbor, etc, was no one dared to ask “And then what?”.
Let us assume the IJN smashed the whole US Navy, even the carriers. And then what?
What is gonna make the USA ship the needed oil to Japan?
Eri Hotta made this point in her book, 1941, Countdown to Infamy and noted the irony of the position of many of the military leaders. In the wild circus which was the substitute for careful consideration of the most important decision any of these leaders would ever take, they had a choice between giving diplomacy more time or rushing headfirst into war. Collectively, they overwhelmingly rejected the route of further diplomacy, yet the unstated understanding was that a satisfactory solution would have to be acquired through diplomatic means.
Yamamoto’s harebrained scheme of attacking or threatening Hawaii has been said by some to be the idea that taking that would force the US to negotiate an acceptable deal. I’m not certain that was actually his thoughts, but it’s an interesting take. Certainly, if that was his goal, the failure to consider logistics is inexplicable and reckless.
Japanese leaders completely underestimated the degree of resolve that the US showed once Pearl Harbor was attacked. Japan’s diplomatic experience was still quite shallow to begin with, and with the military running the show they didn’t have a chance. They were simply over their heads.
The idea was to take it from the Dutch East Indies and such. Without US Navy opposition they could have done that.
The “strategic” plan, such as it was, hinged on a relatively quick negotiated cease fire with the Allies, which as we know was about as likely to happen as the Earth being invaded by space aliens, but the Japanese did not have a clear understanding of Allied intentions, and, as discussed upthread, didn’t have a clear decision making process at all.
It is, to be honest, genuinely impressive that Japan got as far as it did given the chaotic nature of its governance.
Do you suppose Germany’s declaration of war might have also strengthened the resolve of FDR for a war with Japan? Because of course what he really wanted was war with Germany. How might he have dealt with Japan if Germany had denied him a clean entry into the European war, and withheld its declaration of war against the US? Britain would still have been facing Germany (along with Japan), and the US would have been facing just Japan, at least officially. As an added “bonus,” FDR might have had a harder time selling lend-lease-type activities as people wondered openly, “Why are we giving away arms to the UK to fight a country we are not at war with and which has done us no harm, when we have our own war to fight against those ‘dastardly’ Japanese?”
I could almost, almost, almost see FDR, if not the American people, being willing to negotiate with the Japanese if indeed US losses were severe enough, if in the meantime he was still trying to guide the US into a war against Germany.
Which is not to say that I think its much more likely that the US would have negotiated a peace with Japan, only that Germany’s willingness to play into FDR’s hands no doubt changed his own calculus towards Japan (yes they were a distraction from the war in Europe, but no longer a road block to declaring war against Germany), if not the American people’s.
Really, truly, I have always been fascinated by just how inept the Axis powers were. To the extent that independent action might have actually been fitted them, they did not seem to realize it. To the extent they might have acted in concert with one another (specifically against the USSR), they didn’t even try. Even the USSR and the western allies, partners of convenience though they may have been, did more to coordinate than the Axis powers who kicked the whole war off.