Navajo Code

The Navajo code has recently been the subject of a Hollywood film, Windtalkers, starring Nicholas Cage. The code is also discussed in The Code Book - below you will find an extract. Read on to find out more about the facts behind the Hollywood fiction…

During the Pacific campaign, American commanders began to realise that cipher machines had a fundamental drawback. Although electromechanical encryption offered relatively high levels of security, it was painfully slow. Messages had to be typed into the machine letter by letter, the output had to be noted down letter by letter, and then the completed ciphertext had to be transmitted by the radio operator. The radio operator who received the enciphered message then had to pass it on to a cipher expert, who would carefully select the correct key, type the ciphertext into a cipher machine, and thereby decipher it letter by letter. The time and space required for this delicate operation is available at headquarters or on board on a ship, but machine encryption was not ideally suited to more hostile environments, such as the islands of the Pacific, the site of many intense conflicts.

One war correspondent described the difficulties of communication during the heat of jungle battle: "When the fighting became confined to a small area, everything had to move on a split-second schedule. There was not time for enciphering and deciphering... At such times, the King’s English became a last resort - the profaner the better." Unfortunately for the Americans, many Japanese soldiers had attended American colleges and were fluent in English, including the profanities. Hence, information about American plans and tactics was falling into the hands of the enemy.

Philip Johnston, an engineer based in Los Angeles, was one of the first people to react to this problem. At the beginning of 1942, he began to formulate an encryption system inspired by his childhood experiences. The son of a Protestant missionary, Johnston had grown up on the Navajo reservations of Arizona, and as a result he became fully immersed in Navajo culture. He was one of the few people outside the tribe who could speak their language fluently, which allowed him to act as an interpreter for discussions between the Navajo and government agents. This culminated in a visit to the White House, when, as a nine-year-old, Johnston translated for two Navajos who were appealing to President Theodore Roosevelt for fairer treatment for their community. Fully aware of how impenetrable the language was for those outside the tribe, Johnston was struck by the notion that Navajo, or any other Native American language, could act as a virtually unbreakable code. If each battalion in the Pacific employed a pair of Native Americans as radio operators, secure communication could be guaranteed.

He took his idea to Lieutenant Colonel James E. Jones, the Area Signal Officer at Camp Elliott just outside San Diego. Merely by throwing a few Navajo phrases at the bewildered officer, Johnston was able to persuade him that the idea was worthy of serious consideration. A fortnight later he returned with two Navajo, ready to conduct a test demonstration in front of senior Marine officers. The two Navajo were isolated from each other, and the first one was given six typical messages in English, which he translated into Navajo and transmitted to his colleague via a radio. The Navajo receiver translated the messages back into English, wrote them down, and handed them over to the officers, who compared them with the originals. The game of Navajo whispers was flawless, so the Marine officers authorised a pilot project and ordered recruitment to begin immediately.

Before recruiting anybody, however, Lieutenant Colonel Jones and Philip Johnston had to decide whether to conduct the pilot study with the Navajo, or select another tribe. Johnston had used Navajo men for his original demonstration because he had personal connections with the tribe, but this did not necessarily mean that they were the ideal choice. The most important selection criterion was simply a question of numbers; the Marines needed to find a tribe capable of supplying a large number of men, who were fluent in English and literate. The lack of American government investment meant that literacy was very poor on most of the reservations, and attention was therefore focussed on the four largest tribes: the Navajo, the Sioux, the Chippewa, and the Pima-Papago.

The Navajo were the largest tribe, but they were also the least literate, while the Pima-Papago were the most literate, but much fewer in number. There was little to choose between the four tribes, and ultimately the decision rested on another critical factor. According to the official report on Johnston’s idea: "The Navajo is the only tribe in the United States that has not been infested with German students during the past twenty years. These Germans, studying the various tribal dialects under the guise of art students, anthropologists, etc., have undoubtedly attained a good working knowledge of all tribal dialects except Navajo. For this reason the Navajo is the only tribe available offering complete security for the type of work under consideration. It should also be noted that the Navajo tribal dialect is completely unintelligible to all other tribes and all other people, with the possible exception of as many as 28 Americans who have made a study of the dialect. This dialect is equivalent to a secret code to the enemy, and admirably suited for rapid, secure communication."

When America entered the Second World War, the Navajo lived in harsh conditions and were treated as inferior people, and yet the Tribal Council supported the war effort and declared a statement of loyalty: "There exists no purer concentration of Americanism than among the First Americans." The Navajo were so eager to fight that some of them lied about their age, or gorged themselves on bunches of bananas and swallowed gallons of water in order to reach the minimum weight of 55 kilograms. Similarly, there was no problem in finding suitable candidates to be Navajo code talkers, as they were to become known. Within four months of the bombing of Pearl Harbour, 29 Navajo, some as young as fifteen, began an eight-week communications course with the Marine Corps.

Before training could begin, the Marine Corps had to overcome a problem that had plagued the only other code to have been based on the Native American language. During World War One in Northern France, Captain E.W. Horner of Company D, 141st Infantry, ordered that eight men from the Choctaw tribe be employed as radio operators. Obviously none of the enemy understood their language, and so the Choctaw provided secure communications. However, this encryption system was fundamentally flawed, because the Choctaw language had no equivalent for modern military jargon. Hence, a message involving a specific technical term might have to be translated into a vague Choctaw expression, and then there would be a risk that this could be misinterpreted by the receiver.

The same problem would have arisen for the Navajo, but the Marine Corps planned to construct a lexicon of Navajo terms to replace otherwise untranslatable English words, thus removing any ambiguities. The trainees helped to compile the lexicon, and they tended to choose words describing the natural world to indicate specific military terms. Thus, the names of birds replaced types of planes, and fish replaced ships:

Within eight weeks, the trainee code talkers had learnt the entire lexicon and alphabet, thus avoiding the need for codebooks, and thereby removing the risk of material falling into enemy hands. For the Navajo, committing everything to memory was trivial, because traditionally their language did not have a written script, and so they were used to memorising their folk stories and family histories. William McCabe, one of the trainees, said: "In Navajo everything is in the memory - songs, prayers, everything. That’s the way we were raised."

At the end of their training, the Navajo were put to the test. Senders translated a series of messages from English into Navajo, transmitted them, and then receivers translated the messages back into English, using the memorised lexicon and alphabet when necessary. The results were word perfect. To check the strength of the system, a recording of the transmissions was given to Navy Intelligence, the unit that had cracked Purple, the toughest Japanese cipher. After three weeks of intense cryptanalysis, the Naval codebreakers were still baffled by the messages. They called the Navajo language a "weird succession of guttural, nasal, tongue-twisting sounds … we couldn’t even transcribe it, much less crack it." The Navajo code was judged a success. Two Navajo soldiers, John Benally and Johnny Manuelito, were asked to stay and train the next batch of recruits, while the other 27 Navajo code talkers were assigned to four regiments and sent to the Pacific.

Japanese forces had attacked Pearl Harbour on December 7^th, 1941, and soon after they dominated large parts of the Pacific. Japanese troops overran the American garrison on Guam on December 10th, they took Guadalcanal, one of the islands in the Solomon chain, on December 13th, Hong Kong capitulated on December 25th, and U.S. troops on the Philippines surrendered on January 2nd, 1942. During the following summer, the Japanese planned to consolidate their control of the Pacific by building an airfield on Guadalcanal, a base for bombers which would enable the destruction of Allied supply lines, thus making any Allied counterattack almost impossible. Admiral Ernest King, Chief of American Naval Operations, urged an attack on the island before the airfield was completed, and on 7 August the US 1st Marine Division spearheaded an invasion of Guadalcanal. The initial landing parties included the first group of code talkers to see action.

Although the Navajo were confident that their skills would be a blessing to the Marines, their first attempts generated only confusion. Many of the regular signal operators were unaware of this new code, and they sent panic messages all over the island, stating that the Japanese were broadcasting on American frequencies. The colonel in charge immediately halted Navajo communications until he could convince himself that the system was worth pursuing. One of the code talkers recalled how the Navajo code was eventually brought back into service: "The colonel had an idea. He said he would keep us on one condition: that I could out-race his ‘white code’ - a mechanical ticking cylinder thing. We both sent messages, by white cylinder and by my voice. Both of us received answers and the race was to see who could decode his answer first. I was asked, "How long will it take you? Two hours?" "More like two minutes," I answered. The other guy was still decoding when I got the roger on my return message in about four and a half minutes. I said, "Colonel, when are you going to give up on that cylinder thing?" He didn’t say anything. He just lit up his pipe and walked away."

The Navajo code talkers soon proved their worth in the battlefield. During one episode on the island of Saipan, a battalion of Marines took over positions previously held by Japanese soldiers, who had since retreated. Suddenly a salvo exploded nearby. They were under friendly fire from fellow Americans, who were unaware of their advance. They radioed back in English explaining their position, but the salvos continued, because the attacking U.S. troops were suspicious that the messages were Japanese impersonators trying to fool them. It was only when a Navajo message was sent that the attackers realised their mistake and halted the assault. A Navajo message could never be faked, and could always be trusted.

The reputation of the code talkers soon spread, and by the end of 1942 there was a request for 83 more men. The Navajo were to serve in all six Marine Corps divisions, and were sometimes borrowed by other American forces. Their war of words soon turned the Navajo into heroes. Other soldiers would offer to carry their radios and rifles, and they were even given personal bodyguards, partly to protect from their own comrades. On at least three occasions, code talkers were mistaken for Japanese soldiers and captured by fellow Americans. They were only released when colleagues from their own battalion vouched for them.

The impenetrability of the Navajo code was all down to the fact that Navajo belongs to the Na-Dene family of languages, which has no link with any Asian or European language. For example, a verb is not conjugated solely according to its subject, but also its object. The verb ending depends on which category the object belongs to: long (e.g. pipe, pencil), slender and flexible (e.g. snake, thong), granular (e.g. sugar, salt), bundled (e.g. hay), viscous (e.g. mud, faeces) and many others. The verb will also incorporate adverbs and whether or not the speaker has experienced what he or she is talking about or whether it is hearsay. Consequently, a single verb can be equivalent to a whole sentence, making it virtually impossible for foreigners to disentangle its meaning.

Despite its stengths, the Navajo code still suffered from two significant flaws. First, words that were neither in the natural Navajo vocabulary nor in the list of 274 authorised code words had to be spelt out using the special alphabet. This was time consuming, and so it was decided to add another 234 common terms to the lexicon. For example, nations were given Navajo nicknames; Rolled Hat for Australia, Bounded by Water for Britain, Braided Hair for China, Iron Hat for Germany, Floating Land for the Philippines, and Sheep Pain for Spain.

The second problem concerned those words that would still have to be spelt out. If it became clear to the Japanese that words were being spelt out, then it would eventually be possible to use frequency analysis to identify which Navajo words represented which letters. It would soon become obvious that the most commonly used word was Dzeh, which means Elk and which represents e, the most commonly used letter of the English alphabet. Just spelling out the name of island Guadalcanal and repeating the word Wol-la-chee (Ant) four times would be a big clue as to what term represented the letter a. The solution was to add more words to act as extra substitutes (homophones) for the most commonly used letters. Two extra words were introduced as alternatives for each of the six most common letters (E, T, A, O, I, N), and one extra word was introduced for the next six most common letters (S, H, R, D, L, U). For example, now the letter "A" could also substituted by the words Be-la-sana (Apple) or Tse-nihl (Axe). Thereafter, Guadalcanal could be spelt with only one repetition: Klizzie, Shi-da, Wol-la-chee, Lha-cha-eh, Be-la-sana, Dibeh-yassie, Moasi, Tse-nihl, Nesh-chee, Tse-nihl, Ah-jad (Goat, Uncle, Ant, Dog, Apple, Lamb, Cat, Axe, Nut, Axe, Leg).

As the war in the Pacific intensified, and as the Americans advanced from the Solomon Islands to Okinawa, the Navajo Code talkers played an increasingly vital role. During the first days of the attack on Iwo Jima, more than 800 Navajo messages were sent without error. According to Major General Howard Conner: "Without the Navajos, the Marines would never have taken Iwo Jima." The contribution of the Navajo code talkers is all the more remarkable when you consider that, in order to fulfil their duties, they often had to confront and defy their own deeply held spiritual fears. The Navajo believe that the spirits of the dead, chindi, will seek revenge on the living, unless ceremonial rites are performed on the body. The war in the Pacific was particularly bloody, with corpses strewn across the battlefields, and yet the code talkers summoned up the courage to carry on regardless of the chindi that haunted them. In Doris Paul’s book "The Navajo Code Talkers", one of the Navajo recounts an incident which typifies their bravery, dedication and composure:

Altogether, there were 420 Navajo code talkers. Although their bravery as fighting men was acknowledged, their special role in securing communications was classified information. The government forbade them from talking about their work and their unique contribution was forgotten. Just like Turing and the cryptanalysts at Bletchley Park, the Navajo were ignored for decades. Eventually, in 1968 the Navajo code was declassified, and the following year the code talkers held their first reunion. Then, in 1982, they were honoured when the U.S. Government named August 14th "National Navajo Code Talkers Day."

However, the greatest tribute to the work of the Navajo is the simple fact that their code is one of very few throughout history that was never broken. Lieutenant General Seizo Arisue, the Japanese chief of intelligence, admitted that, although they had broken the American Air Force code, they had failed to make any impact on the Navajo code.

To find out more I would recommend the excellent Navajo Code Talkers website.

To see the official Navajo Code Talker's Dictionary as used by the U.S. Military Forces, click here.

You can find out more about the Hollywood film 'Windtalkers' by clicking here.