On August 3. and 4. 1964, the Danish pianist Tom Prehn was in the studio in Aarhus with his musical friends Fritz Krogh (ts), Poul Ehlers (b) and Finn Slumstrup (dr) to record two free compositions for, if possible , release on disc. But the record did not come out until now, in 2021. Previously, the recording "Centrifuga" has only been available on reel-to-reel tape, and has for a long been a collector's item for those who have enough time and money for such activities. And the result of two days in the studio is very exciting. These are either four musicians who were very early in their understanding of free improvised music, or they took the chance that this was the future, and went "all in" in the free-flowing improvisations. And what we hear is simply shockingly good. That there should be musicians in Denmark who played this type of jazz already in 1964 is a big surprise, at least for me. This was at a time when the American swing and bop stars began to come to Copenhagen, and what we hear from these four young guys is far ahead of what Dexter Gordon, Ben Webster, Stuff Smith and the others who played at the clubs around at that time. Prehn's piano playing can be compared to ab early Paul Bley and occasionally with what Cecil Taylor was doing at that time. But I think Taylor was later out with that kind of free improvisation as this quartet performs. But nowadays we have become accustomed to hearing free jazz in a completely different way than we were at the time. Prehn is a creative and exciting pianist, who throws himself into the music without a safety net, and he is well followed by Slumstrup’s great playing on drums, who is listed as the only soloist on the original record cover, and who plays creatively, originally and tough, Poul Ehlers fine and ongoing bass playing are not very different from Jimmy Garrison and, at least, Fritz Krogh's raw tenor saxophone playing, is some of the toughest I can remember hearing, if we disregard the late John Coltrane, Mats Gustafsson, Peter Brötzmann and a couple of others. The fact that this recording has been re-released gives a relatively new picture of what Danish jazz was in the "old days". We can easily take it for granted that Danish jazz was shaped by the many American star musicians who came to the country. But there we have made a solid mistake. For Tom Prehn's quartet was out very early with some of the toughest free jazz we've ever heard from musicians from the North.