In February 1975, Keith Jarrett turned up at the Cologne Opera House to play a solo concert. He was tired, hungry and in pain, and the Bösendorfer piano was falling apart. Technicians worked on the instrument before and after that night’s opera performance, and the 18-year-old promoter talked Jarrett into going on. Still tired, still hungry (dinner arrived too late), still in pain, and very much against his better judgement, Jarrett took the stage at 11.30pm and played what we now know as The Köln Concert, the biggest selling solo jazz album and biggest solo piano album of all time. Jazz pianist and composer Matt McMahon joins Andy at the ABC’s well-maintained Bösendorfer to talk us through that night and its resultant music.