Yochk'o Seffer (sometimes credited as "Jeff Seffer") is a wind player — most commonly alto saxophone — mostly active in the realm of progressive rock. He's been involved in many of the most popular groups within the zeuhl genre. Questioned on his influences, Seffer's has had this to say: "My grandfather is Béla Bartók and my father is John Coltrane".

Yochk'o Seffer was born in Hungary in 1939, and became a refugee to France in 1956. After spending much of the 1960s in Paris playing with a host of jazz musicians in a variety of clubs, Seffer was recruited by drummer and composer Christian Vander to play in zeuhl-founders Magma. His playing with Magma can be found on the album 1001° Centigrades, as well as with Univeria Zekt, a short-lived Magma side project. After two years he left Magma and with ex-Magma keyboardist Francois Cahen founded the band ZAO (not to be confused with the metal band), with whom he appeared on most of the band's recordings. During this time he also had stints with a improvisational jazz group named Perception (also not to be confused with other artists sharing the name) and a jazz-rock group named Speed Limit.

After recording ZAO's fourth album, Seffer disbanded the group to embark on a number of different solo efforts. His first and perhaps most important such endeavor was under the name Neffesh Music, which saw the recording of three LPs in the late 1970s (Delire, Ima, and Ghilgoul). The style of these records are distinctly zeuhl but reflect more of Seffer's musical roots. In the early 1980s he released the "Chromophonie" set of albums (see Chromophonie I/Chromophonie II, and his "YOG" series, containing Yog I: Pitchipoy, Yog II: Sefira and Yog III, began in the mid-1990s.

Yochk'o Seffer has collaborated with a panoply of musicians over his decades-long musical career and produced some of the most acclaimed zeuhl records. Seffer has stated that he is persuaded that the continued research of innovation is necessary to the evolution of the musical language, but that the language has no direction unless it has aligned itself with a personal progression. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.