"Sails of Charon" and Ulrich Roth's Exotic Scale Revolution
As an old school heavy rock devotee and student, it's both fun and educating for me to trace back the incorporation of the diminished scale into the genre. When I first heard this song in 1978 I was a bit overwhelmed, as the sound was very dissonant for said genre at the time. After a few more listens the song's catchiness grew more and more on me, and I could identify the precedent it descended from. I'd heard earlier stabs at diminished licks from Ritchie Blackmore, both from bootleg Deep Purple live tracks (during the earliest months with Ian Gillan), and on songs like Pictures of Home. But Ulrich Roth was the first I'd ever heard to completely embrace and exploit the scale. Its incorporation into the Eastern mode that predominates the song Sails of Charon produced a completely new sound altogether, resolutely distinct from the things Blackmore was contemporarily exploring in Rainbow. This impact of this revolution in sound, one which culminated in the less original but often stunning 1980's work of Yngwie Malmsteen, cannot be underestimated.
Pete Townshend of the Who stated that when he first saw Hendrix (paraphrase): "I could see what he was doing (borrowing from players before), but he was doing something entirely different with it". That most adequately describe the take on heavy rock modes that Uli Roth brought to the table in 1978, a monumental and far reaching achievement in Rock guitar history that was unfortunately overshadowed by the ascendancy of the equally innovative Edward Van Halen that same year.