 Thank you very much for that very kind introduction. I'm sorry I have to make one correction. I don't work for the Naval Security Agency, it's the National Security Agency. Some of you may have heard of it already. But I would like to thank, thank you for the welcome. I'd like to thank those who invited me and the staff people who made my visit possible. It's an honor to be here and I'm very happy to be able to talk on this important anniversary. We are commemorating not just a victory, but one of the great battles in world history and a victory for our side. We are commemorating, memorializing, those who sacrificed their lives for us at this battle. Now I'm making the assumption that everyone sitting in this room knows more about the Battle of Midway than I do from an operational standpoint. If you don't, shame on you. But I would like to address one of the aspects of the battle that is often sidelined or little known and that is the communications intelligence side of it. Sometimes Midway is referred to as a miracle victory. I don't think there was a miracle about it. It was a hard fight. Certainly American forces got some unexpected breaks by bad decisions made by our adversary. But it was one, not because of some sort of supernatural miracle, but through the hard work, the sacrifice, the daring of those who fought the battle. But for those who fight the battle, there's got to be background information. There's got to be intelligence. For most of American history, it comes as something of a surprise to many people, the United States has not been interested in intelligence activities. It's really kind of ironic with all the budget assets expended on it today with the fact that the government seems obsessed with it and our government obsession with it is exceeded only by the obsession of the media with intelligence activities. That this has not been a major part of American life until about 1941, 42. Until that time, it was a small effort carried out by a number of highly trained professionals or perhaps I should say highly experienced professionals. But they had to prove themselves before it could be used. And that's part of the story today. We can't just walk into the Battle of Midway story without some preparation on the intelligence background. Since World War II, the United States has not been without intelligence activities or intelligence agencies. But prior to World War II, career-minded officers did not go into intelligence. They went into one or another branch of the combat arms, left intelligence if it was done at all to the WIMPs. But the WIMPs turned out to have an absolutely essential part of the story. In the 1930s, the US military was beginning to remake itself, a recognition by most senior officers in the Army and the Navy that the world was changing. It was becoming a much more dangerous place. And the United States might not be able to avoid a future war. Then Lieutenant Commander Lawrence Safford had a vision of his own. From the late 1920s, he lobbied the Chief of Naval Operations to start a code-breaking operation within the US Navy. He argued that code-breaking had been important in World War I. If the US became involved in another war, we would need it again. It behoved us in time of peace to begin training at least a cadre organization that could expand rapidly should war come. The CNO saw the wisdom of this and authorized Safford to establish what was first known as the research desk. It was renamed OP20G soon after. That designation meant that it was part of the CNO's staff. In both the Army and the Navy as a sidelight, the code-breaking organizations were not subordinate to military intelligence. They were subordinate in the Army to the Signal Corps and in the Navy to the Chief of Naval Operations staff. This required quite a number of organizational contortions when war came in order to provide the code-breaking organizations with the requirements needed and to facilitate the movement of intelligence from them. The Navy required that all its code-breakers be active duty officers. It was done down in the depths of the District of Columbia. This is the old Army Navy building. It's now in the approximate location of what is now the Vietnam Memorial, but it was an active office building until the end of World War II. Just about the time of the Battle of Midway, the Navy Cryptologic Organization moved to a new home on Nebraska Avenue in the District of Columbia. This was a former girl's school that was taken over as the Navy's Cryptologic Headquarters. Today it is the headquarters of the Homeland Security Department, but I was there about a year and a half ago and many of the street names and a couple of the building names still reflect its Navy heritage. One of the great features of cryptologic activities that is dealing with codes and ciphers is that it attracts a lot of eccentrics. Thomas Dyer, whom you see on the right, worked in cryptology from his early days as a lieutenant, but eventually rose to captain. He had a sign on his desk where he went that said, you don't have to be crazy to work here, but it certainly helps. Joseph Wenger was a man who had had his sense of humor surgically removed. He was all business and it may be for that reason that he became the first code breaker to achieve flag rank. All of them were business, but business oriented. They stuck to the mission, but in many cases they found the fun in what they did as well. Cryptology has a way of getting into your blood. Now the Navy requirement was that all its crypt analysts or code breakers, as we might call them, had to be active duty officers, which meant in those days, all male, all white. The one exception being a civilian female named Agnes Driscoll, she was the best of them all. They used her to train her male colleagues in how to break codes. She had been working in cryptology in one guys or another since World War I. She had had some private business experience in cryptology as well. Thoroughly understood the business. In the 1930s, as the Navy organization solved some Japanese training codes, certainly the reports on this were signed by the male officers in charge of the organization. But in one of them, they remarked, the first break into this difficult training code system used by the Japanese was made by Mrs. Driscoll, as usual. She really was the best. The Navy also had a vigorous program for language analysts. Officers would be dropped into a native environment. They would live on the economy in a particular country. They would study with a tutor. And if they didn't mess up on examinations or cause trouble otherwise, they would live two years on the economy and come back fairly fluent in the language. The Navy's concentration was on Japan. It had several officers living in Tokyo. They studied with a tutor named Naganuma who taught them to read newspaper-level Japanese, which is what turned out to be the level of writing that Japanese naval reports were written in. One veteran of that program wrote a rather overheated article calling Mr. Naganuma, the man who lost the war for Japan by training so many foreigners in the language. That's a bit overstatement, but certainly the fact that we had officers fluent in Japanese was exceedingly important. What we are talking about, and when we talk about this cryptologic organization, OP20G, is communications intelligence. Usually referred to by its acronym, COMINT. This is a unique source of intelligence. It is not filtered through reports by spies or other observers who may be unreliable or have particular agenda of their own. This is what an adversary says to himself. This is taking his own communications and turning them back against him. There are two related disciplines. One is called traffic analysis. This was referred to in the good introduction. This is analyzing the pattern of communications which can teach you things about the adversary's order of battle, about his locations, about his priorities, even if you cannot solve the message lying underneath. And direction finding, which is to determine the angle from which an enemy signal is coming. If you can do this from three locations, it's a simple mathematical formula to determine where the enemy transmitter is. At the same time, the CNO authorized Safford to begin this research desk or OP20G. He also authorized Safford to select some of the best radio men in the American Pacific Fleet and train them in how to eavesdrop on Japanese communications. Codebreaking skill, no matter how highly developed, doesn't matter if you don't have the raw material to work on. So they selected first about 10 radio men, ran successive classes of about 10 to a dozen at the Navy building that I showed the picture of in downtown D.C. Because it was a secret activity, they didn't have cleared spaces the way we do today, no such thing as a vault. They built a wooden shack on top of the Navy building where they held their classes. This led to the group being called the On the Roof Gang. I mean, you had to call them something. And this was a nickname, and it became one of the more exclusive clubs in the Navy. They were deployed overseas, as well as a few places around the United States to eavesdrop on Japanese communications. Now I should point out the Japanese were doing the same thing, but we were better and we had better locations. We also had a ship bristling with antennas that we would sail through the Japanese fleet when it was conducting war games or maneuvers. This collected all kinds of good information, but it also had the effect of tipping off the Japanese to what we were doing. The material from these overseas sites was sent back to Washington DC for processing by the famous China Clipper. This was a process that did not depend on speed. I think one of the important things to remember about all intelligence activities, but particularly about communications intelligence activities is that in the 1930s and 40s and today it requires something that in all our abundance, the United States has very little of and that's patience. The activity has to be undertaken without a guarantee of results. It has to be flexible and it generally takes a lot of time to build up the expertise, to build up the knowledge, to be able to read an adversary's communications. That was certainly true in the paper and pencil era of the 1930s and 1940s, but it is still even true in the computer age today. There's never any guarantee of success no matter how powerful our computers and it still is likely to take a lot of time with false starts and just general building up of knowledge. Japanese conducted triennial grand maneuvers and in the years in between, they would conduct localized maneuvers. The US Navy Cryptologic Organization studied these to a fairly well. Sometimes it would study them from different perspectives. One year they decided not to try breaking any of the Japanese training codes, just to study it from a traffic analysis and direction finding standpoint. Still learned a lot, but it also proved out these disciplines as ways that would produce information eventually. This study was done largely for the education of the cryptologists, but incidental to this kind of training, the Navy Organization learned exceedingly important information. It was a byproduct of training, but it attracted the attention of the senior figures in both the Navy and the rest of the government. First of all, they were able to compile a nearly complete list of all the combat ships in the Japanese Navy. As war broke out, this list was still valid and it became exceedingly important for intelligence officers in strike forces for determining who their adversaries were. They also learned the interesting fact that existing Japanese battleships were faster, better armed than anything we even had on the drawing board. This information caused the senior Navy leadership to reevaluate our procurement program and we designed and procured battleships that were much faster and better armed than anything we had intended and were giving us an edge over the Japanese ship's equivalent. The main code-breaking effort was centered in the District of Columbia, but because communications then were somewhat primitive for long-distance communications, they established some branch locations for the cryptologic organizations. One of them was at Pearl Harbor. It was known eventually as Station Hypo. This is how historians managed to refer to it. The building is still there. There is a plaque over the door. I think it's now being used as a storehouse. One of the things my office would like to do is have a real memorial there to the cryptologists at Pearl Harbor. The person put in charge of Station Hypo was Joseph Rochford. He was an expert code-breaker. He had studied in Tokyo. It was fluent in the Japanese language and he was totally dedicated to the job, which often caused the senior brass to come down on him. He was never, of course, disrespectful, never disobeyed an order, but he would get focused on the job. He would spend several days and nights at Station Hypo, which meant he didn't take a shower. His desk was littered with wax paper from the sandwiches brought in. It was cold in Station Hypo, so he often wore a bathrobe around his uniform. Perfectly understandable when you know the environment and when you know the kinds of work he was doing, but not always guaranteed to meet with the approval of those who didn't know what he was doing or didn't know the environment. So he was constantly thought of as a sloppy officer, as an officer without discipline. But in fact, he was the driving force behind the early successes at Station Hypo. He worked with Admiral Nimitz's Chief Intelligence Officer, Edwin Layton. Layton also had been a language officer in Tokyo. The fact that they had this common background helped them to work very closely together and I think some of the successes that they achieved are partly responsible to their compatible personalities. Especially in the early days, Layton was able to vouch for Rochefort before some of the officers who might be critical of his discipline. After some false starts, their main effort was against a Japanese Navy code system, which we called JN-25. It was a mainline Japanese code used extensively throughout Japanese forces. This is what they were confronted with. Just what looks like a bunch of random numbers. No sense at all. But they were expected to turn this into sense. Let's take a quick look at how this operated. It started with a code book that had 30,000 words give or take in it. Once code book word was chosen, that word or that number would be super enciphered from a list of 100,000 random numbers or randomly generated numbers. Show you a hypothetical example. This is what a page from the Japanese JN-25 would have looked like. List of vocabulary words like a dictionary, but instead of a definition, they have a five-digit number. When an officer wanted to send a message, he would give it to his code clerk. Code clerk would go to the code book, substitute that number for the word beside it. So far, so good. But they would then go to a table of randomly generated numbers to be used as an additive. Let's take a hypothetical example. Have the word from the code book. That word will always have the number 69186 connected with it. But then you go to the table of randomly generated numbers, take the next available numbers, and this hypothetical example is at the top, and add them together in non-carrying addition. The product of that addition is what shows up in the message. So, what the task was straightforward. You had to have a mathematically oriented crypto analyst figure out how to strip off that additive number, seeing only the bottom line number, but strip off the additive number and get down to the code book number underneath. Then you had to have a Japanese linguist figure out what that number means in the Japanese language. So, very straightforward. No computers, no handheld calculators. Now, if you understand what I've just said, and if you understand how to reverse engineer that, please see me afterwards, and I'll put you in touch with our recruiting office at NSA, but, well, before the Japanese attack on Hawaii, they had made only a limited recovery from JN25. The Japanese were very security conscious. They knew that we were eavesdropping on them, because they were eavesdropping on us. All countries do this against other countries they are worried about. They took security measures. They would tweak their system. So that every time the analysts at Station Hypo thought they were getting into the system, something would change and they'd have to start over. Now, the attack on Hawaii is perhaps the worst day in America's 20th century. United States was now at war with an army and a navy that was rated below that of, I think, Poland. We were facing the two most powerful militaries in the world, ill-prepared. So we needed the kind of edge that cryptology could give us. We needed to be able to put our forces where they would do the most good. And the only way to do that was through accurate and timely information. One of the things that happened after Pearl Harbor, however, that was of some benefit, was that the Japanese decided not to tweak their code system as they had been doing. They now had ships across the Pacific that could be in combat at any time. They didn't want to lose a battle because some ship didn't get whatever tweak they needed that month. The code breakers friend is a lot of messages in the same system. So before the attack on Pearl Harbor, the Americans were able to solve about 10% of this JN25 code, not enough to read any messages, but very quickly after Pearl Harbor, we were able to read enough to make sense of many of the Japanese messages thanks to the analysis. Should also be said, this is also important, as was said in the introduction, let me reemphasize, the Japanese strike at Pearl Harbor was not to win a war against the United States. This is a myth. The Japanese struck at Pearl Harbor to put us out of the war. They did not want us to intervene when they attacked the Philippines or Southeast Asia. But our main naval weapon, aircraft carriers, though they were the Japanese target, were not at Pearl Harbor on December 7th. They were supposed to be, but they had been delayed returning from a mission. Heaven looks out for fools in the United States of America. I think the Pearl Harbor example proves that old cliche more than anything else. Very early in the aftermath of Pearl Harbor, in the ability to discern Japanese intentions through their messages, we learned that the Japanese were sending an aircraft carrier task force to Port Moresby, New Guinea. They had correctly guessed or analyzed that the United States was going to use Australia as an unsinkable aircraft carrier to build up our forces for the counter punch against the Japanese main islands. If they had a naval base on New Guinea, we wouldn't be able to do that. But as the Japanese themselves were planning this operation, the code breakers at Pearl Harbor, Station Hypo, were reading many of their messages. We learned in a very accurate way the exact strength of the Japanese strike force and the date that the operation was due to commence. For the first time in naval combat, they not only had this strategic forewarning through solving a mainline Japanese code, they had eavesdroppers on the ship listening to the communications of the combatant ships during the battle. This was important, it revealed many of the details of the Japanese tactical response to our presence in the Coral Sea and revealed to us their losses and sometimes revealed to us our own losses, giving the task force commander a much more accurate picture of what was going on during the battle to help them manage it. Now, the history books sometimes put down the battle of Coral Sea as a tie because both sides had the same amount of losses, but it was actually an American victory. It was the first time the Japanese Navy had been stopped from getting anything it attacked, but we would not have even known they were headed for New Guinea if we had not been reading their messages secretly. As the battle for Coral Sea was going on, the messages that we were decrypting from the Japanese Navy indicated that they were planning more operations in the Pacific, including possibly another strike at Hawaii. Admiral Nimitz, though a risk taker, wanted an edge, was a calculated risk, not just a risk that he wanted to take, so he bore down on his intelligence staff. One tipping point was the famous Doolittle Raid over Tokyo in April 1942. This was direct retaliation on the Japanese homeland. Fine example also of Army-Navy cooperation in carrying out a delicate operation. The actual damage inflicted by the Doolittle Raiders in their famous 30 seconds over Tokyo was really minimal, but it was psychologically very severe on the Japanese. It was the Japanese 9-11. The Japanese homeland had not been successfully attacked since the Mongols in the 13th century until the Doolittle Raid. So this inspired, if not panic, at least a greater sense of urgency to get the American carriers that had been missed at Pearl Harbor. The assignment was turned over to Admiral Yamamoto Isoroku, the commander of the combined fleet, the main Japanese fleet in the Pacific. He was perhaps one of the most brilliant strategic thinkers of the Second World War, particularly so since he understood how American Navy officers were trained and how they reacted to different situations. He had been American naval attaché in Washington. He was the poker champion of the diplomatic corps in Washington, but he had much interaction with American Navy officers, many of whom were, at that time, his opponents, or were now by 1942, his opponents. He understood how they would react, and he and his planners came up with a brilliant plan to lure American carriers out of Hawaiian waters where they would have land-based aircraft to protect them by attacking the island of Midway, the last American outpost in the Pacific, knew that Admiral Nimitz could not afford to lose it. There would also be a diversion operation towards the Aleutian Islands with the expectation that Nimitz would split his fleet. When one part of Nimitz's fleet responded to the initial attack on Midway, a second Japanese strike force would come up from the south, the two Japanese forces would catch the Americans between them and crush them. Those assets that had been sent to defend the Aleutians would be ambushed by submarines. A very complex plan for its time, but still a brilliant one. But it began to unravel thanks to the decryption of Japanese messages. Through reading messages from the combined fleet, Station Hypo was able to follow the buildup of two task forces that were being detached from the fleet for operations in the Western Pacific. And this included a landing or perhaps an occupation force. So this was not just a strike and run operation. This is perhaps the key part of what the code breakers learned. This was not simply an attack to gain another island base. It was an attempt to trap the American fleet, to lure it out where it could be surrounded and destroyed. This would greatly affect Admiral Nimitz's planning and decisions for the response to this. But in all these messages, the Japanese did not reveal the location of their initial strike. Everybody seemed to know what it was. They used an abbreviation, AF, an American something. Many of the Japanese designators for American territory had been recovered, but AF had not. Joe Rochefort, the commander of Station Hypo and Edwin Layton, the intelligence officer, based on other older messages, had a hunch that AF was midway, but a hunch was still not up to the standard Admiral Nimitz needed for a calculated risk. So they came up with a clever plan, which Nimitz authorized. They had an undersea cable or connection to Midway Island that the Japanese could not tap. They instructed the garrison at Midway to send a housekeeping message saying that their water filtration plant had broken down. They were running short of water, and of course they needed spare parts as well as a resupply of water. Why did they do this? Because they knew the Japanese were eavesdropping on us the same as us eavesdropping on them. And yes, they broke a Japanese message about two days after this false message saying that the Japanese were reporting that AF was short of water. Japanese Navy thought it had pulled off a really important intelligence coup that would help their invasion force and they would be ready for a water shortage at Midway. What they had actually done however was confirm for the Americans the location of their impending attack. With further analysis, the analysts at Station Hypo were not only able to determine the target of the attack but the date the attack would start. From their fore knowledge, build up early in the war or in the last days of peace, they were able to give a really detailed what turned out to be an accurate order of battle listing all the Japanese ships that would be involved in the operation. So what did Nimitz know? Certainly enough for his calculated risks. Before each operation, the Japanese would not communicate. The ships traveling to strike Pearl Harbor in December 1941 did not communicate with Japan. The strike force headed for Midway did not communicate with their headquarters. So there was a period of doubt as to whether all the information that the code breakers had developed actually was true. But as they moved into position to launch their attacks on Midway, the Japanese communicated with each other ship to ship. This was picked up by the tactical eavesdroppers. Once again, aboard ship as they had been at Coral Sea, some on Midway Island itself. So they confirmed for the task force commander that the information on which our response was based had been accurate. The Japanese were there and they were able to give a general idea of exactly where the Japanese were located. As the battle commenced, the Japanese communicated more. This triangulation of their signals was able to pinpoint much more accurately where their ships were actually located. And the Japanese helped out themselves with some of their messages. It was a desperate fight on our part. We were outnumbered. Japanese were more experienced at combat than we were. But as the Americans began to prevail, Japanese messages revealed their losses and revealed the fact that they were coming into desperate straits. Task force commander had to abandon his flagship. And this was confirmed partly by inference because his communications had been transferred to another ship. They had communications, they intercepted from Japanese pilots searching for their ship, their aircraft carriers to find a landing spot. Their ships no longer were on the surface. The Japanese pilots had to ditch. But there were many desperate calls intercepted. Japanese retreated. They increased their communications. I don't know if they had guessed we were eavesdropping on the battle, but they made it sound as if they had about a third more ships than they actually did still active. And the loss at Midway was to be a military secret. We learned from Japanese orders that nobody without the need to know was to be told about the outcome of the battle of Midway. State secret. Admiral Nimitz rewarded those who had fought in the battle. He also understood the role the code breakers had made. Invited Joe Rocheford up for a bottle of champagne. Rocheford was there still working away in Station Hypo in his bathrobe. He quickly changed into a dress uniform and reported for his ceremonial drink. One of the great ironies of the story of Midway is the fate of Joe Rocheford. He was acknowledged by all the subordinate code breakers and other analysts at Station Hypo to have been the driving force that brought them into a position to read the Japanese messages. But he had angered a few too many people over the undisciplined look that he had. He also believed he was working for Admiral Nimitz. The code breakers also had a line of authority tracing to Washington which resented his emphasis on Admiral Nimitz. So using their contacts in Washington, the code breaking brass there, convinced Admiral King, the Chief of Naval Operations to deny Rocheford the Distinguished Service Medal that Nimitz had nominated him for. And Rocheford was summarily transferred out of Pearl Harbor to command a floating dry dock near San Francisco. Later in the war, he was, to use a phrase from the Cold War, rehabilitated and he worked at the OP-20G headquarters in Washington but never again became a major factor, major force in cryptology. Quote that I like. Navy officer on the aircraft carrier Enterprise, he had been briefed before the battle on the enemy order of battle but he had never been cleared for comment so he was not told where the information had come from and his reaction was that man of ours in Tokyo is worth every cent repaying him. And I think the code breakers liked this sentiment. This is what they hoped everybody assumed about their work. Chief of Naval Operations just before the battle said in a quote that I believe he continued to have faith in was that comment had been important. It was important that Coral Sea was important at Midway but if we lose it, if we lose this access disaster will follow. One of the things that was important about the battles of Coral Sea and Midway was that they educated American officers and gave them a stake in understanding and using comment. Before, I think a lot of them had believed that intelligence was mumbo jumbo, that it comes up by magic and may or may not be right. Something like the gypsy person attended a circus Midway who look into a crystal ball and tell your fortune. But the actions at Coral Sea and Midway convinced the Navy leadership that communications intelligence was the real thing, that it was an indispensable part of all operations. After a period, comment became a fact or a hidden factor but absolute factor that guided most of the rest of the operations in the Pacific War. It's commonly known that our decision to land at Guadalcanal was because an aircraft found a reconnaissance aircraft saw the Japanese building an airfield there. The reconnaissance airplane was there in the first place because we had comment that said the Japanese were building an airfield there and the reconnaissance plane just confirmed this. Most of the island hopping decisions were based on appraisals of Japanese strength on various islands. This continued to the end of the war. In August 1945, the code breakers encountered a Japanese word nobody had ever seen before and an encrypted message. As they studied it with the aid of a dictionary, they realized it was a new word or at least a very little used word that meant burn the emperor's portrait. Japanese were going to burn the emperor's sacred portrait rather than let it fall into enemy hands. That meant the war was over. So this continued on through to the end of the war. Perhaps the best way to end this is to quote Chester Nimitz who shortly after the battle of Midway as the battle for Guadalcanal was unfolding, wrote once again radio intelligence has enabled the fighting force of the Pacific and Southwest Pacific to know where and when to hit the enemy. My only regret is that our appreciation which is unlimited can only be extended to those who are cleared or who can read this system. Though he was fully aware of the contributions that it made. And I should say after the war, we got good. This support continues today. It still takes patience. It still takes shall we call them unique individuals. It still takes an education process for the officers who will be recipients of the information. But the people who are the intellectual descendants of those who worked at Station Hypo are as dedicated to the task at hand and to protecting the United States through cryptology. And that's my story and I'm gonna stick to it. Thank you very much. I'd be very happy to entertain any questions if I haven't already exhausted you as well as the subject. Yes, sir. There is a microphone handy, please use them if you ask a question. I'm Captain Hirata from Japan. Thank you for very good interesting lecture and historical lecture. My question about this cryptor problem. So actually we Japanese officers are studying about it as a lesson learned in the National Defense Academy of Secondary School or anytime we studied about that. So actually Japanese Imperial Navy continue to use same crypto and also they couldn't recognize United States Navy have already understood everything. So what is the cause of failure? It is a Japanese parade or character or Imperial Navy's organizational problem. I'd like to know your opinion. Well if I understand your question is why were we so successful at this? It was not really a Japanese failure. It was I think the fact that the United States was desperate. We had to be innovative. We had to come up with an edge and we were able to mobilize some very unusual but brilliant people to do this. The Japanese also had some success against low level American codes but they never, as I understand it, during the war put the emphasis on code breaking that they put into code making and therefore did not have the same level of success that we did. But we did it because we had to. Perhaps not a satisfactory answer but I'm not sure how you measure the other differences. I think there was one Japanese problem. Japanese assumed they had a last line of defense. There's always, even if they believed the code was unbreakable, there's always the chance that somebody might lose a copy of it or it might be stolen or somebody might sell a copy to the enemy. Japanese seemed to believe that their language was so difficult for foreigners that even if their code was compromised there were no foreigners capable of understanding the underlying plain text which I think was a key failure. Other questions, yes in the back. Commander Ben Boyard, what kind of efforts did the US make when they were acting on intelligence to try to prevent divulging the source of that intel? Yes, good question. The rule in World War II was that no action should be taken on a piece of communications intelligence that would reveal its existence. That is, there had to be some cover story about how the information could have been acquired by other means. So in all theaters of war, even when comment revealed where the enemy was or where the enemy was moving to or what it intended to do, commanders would send out various kinds of unnecessary reconnaissance. Aircraft sometimes land patrols or small ship patrols in such a way that the enemy would be aware of their presence. And the actions taken could be put down to good aggressive patrolling and reconnaissance. And sometimes there were cover stories that were leaked through using codes we knew the enemy could break. And we'd misdirect reasons why we did an action. It was all up to the local commander not to take a precipitated action that would reveal or take an action that would be based only on comment or could have been based only on comment. Yes, hi. Thank you very much, Doctor. That was fabulous. I mean, I picked up bits and pieces over the years but never came close to the broad and intricate picture that you described. I have a question that's somewhat related and what triggered my memory was our fellow comment about Japanese or your comments that the Japanese language was so difficult that they felt that that was their offense against intercept. I've heard that the American Indians did something like that in World War II at the tactical level of communications. So they just simply spoke in their Cherokee or a Native American Indian dialects and languages and it was never broken during the war. That's correct. These were the Native American code talkers. They certainly spoke in their native languages which were unwritten and little understood outside those who had grown up with the language but they also used a kind of verbal code. They would substitute a word from their natural environment for the word of war. For example, the Comanches who did it would refer, they thought a machine gun sounded like a sewing machine, just louder. So they would refer it in their messages to a machine gun as a sewing machine weapon. The Navajo who did it in the South Pacific would, for example, refer to a fighter aircraft as a chicken hawk or a bomber as a pregnant buzzard, things like that. So there was a light sort of verbal code along with their native language which was tough enough. But there's a difference between solving Navajo which is spoken by a couple of thousand and solving Japanese which is spoken by 100,000. Right, thank you. Welcome. Thank you very much for your kind attention.