Systems in Blue is a German pop band originally composed of Rolf Köhler, Michael Scholz, and Detlef Wiedeke. After Köhler's death, singer Olaf Senkbeil was invited to join them.
The original band members started in the beginning of the 1960s, working in different bands during 1960s and 1970s, Köhler worked for several different artists such as Blonker, Uriah Heep, Blind Guardian, Helloween, Grave Digger, Gamma Ray, Iron Savior, Savage Circus, Tokyo, Mephistopheles, and Kin Ping Meh among others. They were part of the choruses of the Dieter Bohlen produced Modern Talking in 1984-1987 and 1998-2000 and Blue System in 1987-1997 with Köhler as the refrain singer.