Eleven years after World War II, when the new [West] German Armed Forces, the Bundeswehr, were established in 1956, there was an urgent need for new cipher systems. The cipher system described here, the Reihenschieber (literally, “sequential, or series, slide”) is a complex hand cipher system for off-line encryption of the late nineteen fifties. The system was developed during 1957 as a joint venture of the Zentralstelle fur das Chiffrierwesen (ZfChi) (Central Office for Cryptology), the Mehlem section of the Bundesnachrichtendienst (BND) (Federal Intelligence Service) and the Femmeldedienststelle der Bundeswehr (FmDSt Bw) (Signal Office of the Bundeswehr). The series-slide cipher system combines elements of a pseudorandom key stream with a limited number of random mixed alphabets. The system may be categorized as being somewhere between a modified Vigenére and a modified running-key (one-time-pad) cipher.