We can (and probably will) argue about exactly what the musical term “heavy metal” means. In the absence of a rigorous definition, we can also argue about what the first heavy metal song was. But however you slice it, the Kinks’ debut single has to be a strong contender. It’s played using “power chords” (i.e. chords consisting only of the root and fifth, omitting the third); it’s played in an aggressive, brutal style; and the guitars are distorted, having been played through a speaker whose cone had been slashed with a razor blade.
The astonishing thing about You Really Got Me is its historical context. The Beatles had only just released their film A Hard Day’s Night, and were supporting it with such forgettable early-era singles as I’ll Cry Instead, Matchbox and Ain’t She Sweet. While nearly everyone was falling over themselves to sound like the Beatles, the Kinks went off in a completely different direction and made their bow with a song that must have been near-incomprehensible to audiences brought up on The Everly Brothers and who thought I Want to Hold You Hand was dangerously iconoclastic.
That’s not to say that the Kinks were immune to the Beatles’ influence — really, who was or indeed is? In this live performance, you can see a very strong early-era Beatles influence in how they present themselves. But the song itself is a million miles away from anything the Beatles were doing at that point.
The Kinks went on to become one of the more successful British Invasion bands, but with an interestingly varied style that saw them not often repeating the approach of You Really Got Me. (At least, not after their second single, All Day and All of the Night, which in truth is uncomfortably close to being a retread of the first). When I think of the Kinks, the first song I think of is Waterloo Sunset, which is about as different as a pop song can be from You Really Got Me (and which is a staple in my own folk-club repertoire).
[Note: for some reason, about 80% of the Kinks videos on YouTube are infected with “This video is not available in your country. Sorry about that” disease, which suggests to me that their prevention-of-publicity team is particularly efficient. So my apologies if the links above have rotted by the time you read this.]