# The Special Fish Report

## Albert W. Small (December 1944)

### Page 94

Tony Sale's
Codes and Ciphers

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Getting a start in Turingery when 300 letters or more of key are

available (and motor dottage is not too low) can also be done by the "5x5

square" method. Steps involved are:

1. Write out delta Key on worksheet. (Regular Turingery

procedure.)

2. Assume a character for delta psi prime in the first position

of delta key. This is to be changed later if found wrong. It is actually

assumed to be a slant.

3. Obtain the resultant delta X signs, and carry them forward

throughout the worksheet to their "multiple" positions. At each of these

points assume either a repeat or a complete anti-repeat in delta-psi-prime,

obtaining thereby the delta X for the whole character. A complete delta X

character so obtained is called a "child."

4. Enter on a width of X1 each induced Delta X1 value (from the

children) together with a subscript showing the basic impulse from which it

was induced. (I.e., in the X1 case, subscripts representing impulses 2, 3,

4, or 5.) Values down the columns tend to be alike, if the originally

assumed delta psi prime character ("slant") was correct. But, down a column,

a cross with a subscript 2 for example and a dot with a subscript 3, would

tend to indicate that the signs of the original delta psi prime assumption

were opposite in impulses 2 and 3. A count is therefore made, in each

column, of the number of agreements and disagreements between each possible

pair of subscripts; these counts, for each pair of subscripts, are then totalled

in terms of excesses of agreements or disagreements. The same procedure is

carried out for X2 X3 X4 and X5 widths. The grand total count for each pair

of subscripts, in terms of excesses of agreements or disagreements, is then

entered in a 5x5 flag which is doubled about the diagonal into a 5x5 square.

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