The Special Fish Report
Albert W. Small (December 1944)
Page 83 1/2
Codes and Ciphers
TOP SECRET Special Fish Report Page 83 1/2
When the psi's were finally out, the Newmanry was telephoned and told
that the X's had been proved. The set of psi's and X's and the messages
were given over to the "setting room" for the motor wheels to be broken,
as described previously.
There are or course variations in technique here as in Newmanry.
Often when the first X has been broken through "counting out," the
corresponding psi prime is obtained, and by numbering the resultant
groups the more certain motor dots can be inferred; whenever we have
motor dots, delta Key is delta X and we can thereby obtain another X wheel
or two and other psi's. This method short-circuits much of the need for
"counting out" as described above.
Also it is not usually necessary to obtain every character of a
X wheel, since "fiddling" with the unknown characters enables the
breaker to assume some missing ones on the basis of known X wheel