C. S. Briefly stated, these departments were as follows:
I. Sixta - Traffic Analysis
II. Hut Six - Cryptanalysis of the German Enigma machine
III. Block F - Cryptanalysis of Fish (German non-morse) Traffic
IV. Hut Three - Evaluation and Exploitation of Message Content
of all German Traffic.
Each department is discussed in some detail in subsequent pages.
Historical Record. The American party first arrivedin Sixta
in October of 1943, four officers and eleven enlisted men strong. This
number was increased during the five following months by the arrival from
time to time of further shipments until the top strength was around twenty
men and six officers. Not all of the original party was included in this
number, however, several of the first arrivals having been trained by Sis
ta and then shifted to Hut Six, Hut Three, or the Quiet Room (liaiso be-
tween Hut Six and Sixta). Other men, after working in Sixta for a while,
went into Control or into the Direction-Finding Section, a specialised
branch of Sixta.
Task of Sixta. "Sixta" is a name derived from a combination of
Hut Six and Traffic Analysis (abbreviated to TA), the latter term being the
clue to the function of the section. The combination indicates that the
section was primarily established as an aid to the cryptanalysis of Hut
Six. When operations got well under way, however, it was found that
traffic analysis produced also much valuable information of an intelligence
nature independent of Hut Six.
Sixta activities broke down into the following divisions:
Log-Reading; Search Party; Fusion Room; Direction-Finding Section; Control;
Wireless Telegraphy Bureau; and Technical Section. It be well to de-
scribe each of these activities briefly because members of the American party