Turing's Treatise on the Enigma

not a success as the rods were incorrectly copied). For the crib
these mystic number rods are shown in position over the inverse rods in Fig 67. Every fifth letter from the top of the mystic number table is also shown.

Another use for the mystic number table is in the making of the Turing sheets. The line of pencil numbers along the top of any sheet is the line of mystic numbers with the sheet number as its line number, and starting at column L. Compare Figs 58, 56.

The mystic numbers can of course be made by actual subtraction from the inverse rods. However it is actually easier to do the calculation in terms of the letters of an upright. It turns out that one can manage with one upright, which one subtracts from itself, staggered various amounts. One can transform the letters into numbers to simplify the subtraction. I shall not give the details of this.

EINS catalogues

In this chapter and the last we have not exhausted all the possible methods of dealing with the Unsteckered enigma, and enigma with known Stecker. When the Umkehrwalz does not rotate we can catalogue the result of encoding a short word such as EINS at every possible position. The details of this are explained in Chapter


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