Once upon a time, my sophomore year in college in fact, a new song from Deep Purple, “Smoke on the Water,” prompted me to play with its strange chord structure on the piano installed in the dormitory ...

Did you know that the devil has a chord? More than a false oath, more than the screams of victims boiling in sulfur, the diminished fifth — say, C to F-sharp — is music to Satan's ears. There's even a ...