The Katakana Code
As Chief Harry Kidder developed the plan for the On-The-Roof Gang training, he had a lot to keep in mind. While the Japanese used international Morse code in communicating with the rest of the world, at home they shunned the use of that code for both domestic and military purposes. It was not that international Morse code was necessarily incompatible with the Japanese language. The Japanese used a system of dits and dahs that was somewhat more responsive to their needs and certainly more succinct than was the code devised by Samuel Morse. In Morse code, for example, it took a total of eight dit and dah combinations to transmit the Romaji characters in the word YOKOHAMA, whereas in the Japanese system, it took only four:
In Morse code, Yokohama: -.-- --- -.- --- …. .- -- .-
In Kata Kana code, Yo-ko-ha-ma: -- ---- -… -..-
The reason for this was quite simple - the Kata Kana alphabet consisted of symbols that are represented in Romaji by a consonant and vowel combination. In Kata Kana, Yokohama is spelled with four symbols: ヨ コ ハ マ.
Therefore, Kata Kana code used roughly half the telegraphic code symbols of Morse code, when taking numbers and punctuation into consideration. Kidder’s curriculum focused firstly and primarily on the Japanese Kata Kana alphabet and the corresponding telegraphic code equivalent.
The Radiomen had to learn the basic Kata Kana alphabet then numbers, punctuation, and some characters unique to the Japanese language. Many of the telegraphic codes were the same as in Morse code, but represented completely different characters. An ‘r’ in Morse code, for instance, was .-. which in the Kata Kana code represented ナ, or the ‘NA’ sound.
The curriculum also included traffic analysis, which allowed operators to be able to glean some value from encrypted messages without the benefit of being able to decrypt them. Not only did information such as this aide the cryptanalysts in their attack upon the text of the encrypted message, but in a wartime situation it could provide valuable intelligence to the U.S. commanders.
The Radiomen would also be taught how to develop an intercept plan based on the skeds of the target network. Every network operated differently, and a proper intercept plan was key to being able to fully exploit its communications.
Lastly, Chief Kidder’s curriculum introduced the Radiomen to cryptanalysis, the art and science of breaking enemy ciphers. This was a skill to which Kidder was only recently exposed. This wasn’t to be a primary skill of the Radio Intercept operators, but it was a chance for the Research Desk to screen for Sailors that might have a special aptitude for the activity.
This was an awful lot to learn in a mere three months. Harry Kidder thought back to the time when he was learning to copy the Kata Kana code and believed it would take very special operators to be able to do what was going to be asked of them.
And that’s exactly what he got.
