雙語暢銷書《艾倫圖靈傳》第5章:解謎接力賽(30)
The method depended upon putting enough of these clues together to deduce that state.
More precisely a core-position would be said to have a 'female' letter, if that letter's encipherment happened to be the same three steps later.
更確切地説，如果一個核位在編碼的過程中，三步之後產生了一個相同的字母，那麼就稱這個核位會產生一隻母雞。This was not a rare phenomenon, but would occur on average one time in twenty-five.
這種現象並不罕見，平均每25次通信中就會出現一次。
Some core-positions (about forty per cent) would have the property of possessing at least one 'female' letter, and the rest would not.
大約有40%的核位會產生母雞。The property of having a female, or not, would be plugboard-independent, although the identity of the female letter would depend upon the plugboard.
是否會產生母雞，與配線板無關，配線板能影響的只是哪個字母是母雞。The analysts could easily locate all the observed females in the traffic of the day.
分析員可以很容易地找出當天通信中所有的母雞。They would not know the core-positions which had given rise to them, but from the openly announced rotor settings like AGH in the example, they would know the relative core-positions.
他們並不知道產生這些母雞的核位，但通過明文形式的盤位（比如例子中的AGH），他們可以得到一個相對的核位，This information yielded a pattern of females
由此可以得出一個母雞模式。Because only about forty per cent of the core positions had females, there might only be one way in which this pattern could be matched with their known distribution.
因為只有約40%的核位會產生母雞，所以基本上一個母雞模式只會匹配一個核位。Here therefore was the new fingerprint—a pattern of 'females'.
這就是他們的新線索。But it was not possible to catalogue in advance all possible patterns, as they had been able to do with the cycle lengths.
然而，他們不可能像歸納輪換長度一樣，提前歸納每一個核位的母雞模式。There had to be some other, more sophisticated means of making the match.
必須要有其它更巧妙的方法，來進行這種匹配。The method they employed made use of perforated sheets.
他們的方法，就是利用打孔卡片。
