Under the pressure of needing a new single for the Christmas market, John Lennon wrote much of the music, including the famous guitar hook, and most of the lyrics, while Paul McCartney helped with the verses.
According to music critic Ian MacDonald, the song "starts as a twelve-bar blues in E, which makes a feint at turning into a twelve-bar in the relative minor
(i.e. the chorus) before doubling back to the expected B—another joke
from a group which had clearly decided that wit was to be their new
gimmick."
Simple but heavy, Jimi Page's riff is one of the undisputed roots of heavy metal music. This timeless simbol of rock is based on E power chords and typical Zepp's bluesy-hard rock style. Page played the loose blues riff for the intro, on a Telecaster through a
100W Marshall "Plexi" head amp with distortion from the EL34 output
valves, which ascends into the first chorus.
Led Zeppelin's bass player John Paul Jones has stated that Page's famous riff probably emerged from a stage improvisation during the band's playing of "Dazed and Confused", but Page denied that: "No. No. Absolutely incorrect. No, it was put together when we were
rehearsing some music for the second album. I had a riff, everyone was
at my house, and we kicked it from there. Never was it written during a
gig--where did you hear that?" And later explained: "I had [the riff] worked out already before entering the studio. I had
rehearsed it. And then all of that other stuff, sonic wave sound and all
that, I built it up in the studio, and put effects on it and things,
treatments".
Music is not a competiton, thats for sure. But if you really had to pick one song, or at least one riff, that is so timeless, so unique and instantly recognizable, to most of the people it would be Smoke on the water by Deep Purple. It just screams HARD ROCK !!!