TheCodeBreakers
been given a roman equivalent, and when Yardley had his typists compile
frequency tables for the twenty-five plain-language kata kana telegrams
he had, he discovered that this script obeyed rules of frequency just like
any other. Specifically, the kana n, the only nonsyllabic kana, was most
common, appearing often at the end of words, followed by i, no, o, ni, shi,
wa, ru, and to, in that order. The list of most common syllables and
words began with ari and continued with aritashi, daijin, denpoo, gai,
gyoo, and so on. At the end of about four months, the typists had
prepared elaborate
I
statistics ot frequency and contact for about 10,000 kana. He then set
them to work dividing the ten-letter groups of the Japanese code
telegrams into pairs of letters and drawing up similar frequency and
contact data for these pairs. He himself went through the approximately
100 code telegrams underlining with colored pencils all repetitions of
four letters or more
annaabi.ee 
