So what, if anything, can be learnt from an analysis of the riffs? Well, here are the five (breakable) rules...

RULE #1

Keep it simple and memorable – generally a handful of notes with the musical essence delivered in a couple of bars. If you can’t sing it back easily (or at least keep it caught in your head) you’ve done something wrong.

RULE #2

Include just the right amount of rhythmic interest. Unless the riff is actively melodic ( Sweet Child O’ Mine and), you should recognise the riff from its rhythm alone. This means a use of space and a simple but effective rhythmic hook.

RULE #3

If you want a fast tempo, keep the riff at quavers or longer, and at slower tempos make significant use of semiquavers; neither frenzied, nor laboured.

RULE #4

Embrace the idiomatic nature of the guitar (open strings, muting, bends and an interplay of chords and single lines) and use effects sparingly, and only if they add a musical element to the track. Swamping your part with distortion, delays and reverbs can compromise the catchiness of a riff when a raw guitar sound might deliver it more effectively.

RULE #5

Feel free to break any of the rules (including this one). Innovation comes from intuition: learn from the past, but don’t let it dictate all your choices. All these riffs are classics precisely because they broke a rule or two...