The Special Fish Report
Albert W. Small (December 1944)
Page 62
Tony Sale's
Codes and Ciphers
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CX/MSS
TOP SECRET Special Fish Report Page 62
likely to give trouble on any date. (The job done by Newmanry today is miraculous;
95% of those marked all certain by Newmanry are "broken on psi's" by Testery.)
As soon as the P text value is decided upon for "stop," the D
is looked at for likely positions of this value. Likely positions are those
giving repeats in PSI' or anti-repeats in PSI', all being compatible with the
limitation if known. For such discovered positions, suspected abbreviations are
tried in the vicinity, and the resultant PSI' text is written out. This
is condensed where possible, and the crosses, and dots of S1,S2,S3, and S5
jotted dawn on cross-section paper where they are studied to see if actual
wheel patterns can be matched. If not, the PSI' pattern is extended each way,
with either a repeat or an anti-repeat, and the resultant plain-text studied,
new guesses written in, and further PSI' obtained. From this material,
multiple possibilities for setting the PSI wheels are considered, and the
equation D + PSI'= P worked back and forth between possible PSI' and possible P,
until the PSI is set in at least one level. When it is set uniquely on at
least one impulse, it is then possible to project forward or backward to another
stretch of D where text has been guessed, using the known motor dottage as
an aid, and try to establish the distance between the two stretches on the known
PSI wheel. Since this is the same for all PSI wheels, the others can be
strengthened with the increased data from both plain-text-guesses, and
possibly they can also be set.
Since in general the guessed-in cribs should be as close together
as possible, the problem is to guess in as much as can be done, even if some is
wrong. Thus they are constantly guessing in and testing assumptions, and the
busier they keep the sooner the psi's are set. A quiet, unhurried speed
is the essential of a good worker, who writes little, and does much mentally.
Powerful aids to psi setting exist. The D worksheet has been marked
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