It was back in 1964 when the world became mystified by the opening chord of The Beatles’ “A Hard Day’s Night.” What were John and George playing? (Macca provided a bass note.) According to Harrison, it was “an F with a G on top.” It took Randy Bachman to crack the real code many years later.
Mystery solved. Now what about Noel Gallagher’s “secret chord” from “Don’t Look Back in Anger?” This one may have been cracked, too.
(Thanks to Danny for the link.)