[1] The cipher was designed by the astronomer and sometime cryptographer Walter Fricke while working as a conscript in Section IIb, of Group 2 of OKW/Chi and introduced in March 1944 and the Allied forces codebreakers had considerable difficulties in breaking it.
[2] Cryptanalysis, if successful, generally required a 40 letter crib (known plaintext) and some two weeks, making the tactical information outdated before it could be exploited.
The combination of strength and ease of use made RS 44 an ideal hand cipher.
[1] The message key contains the start position of the text in the grid, designated by the column and header digraphs.
[1] The secret variable start cell and first column ensure a unique transposition for each message, making multiple anagramming very difficult.