As the original kings of thrash metal, Metallica have dominated the global metal scene since the 1980s with some of the biggest riffs ever to fill a stadium. In Kirk Hammett and James Hetfield the band have the best of both worlds - a virtuoso technician and a razor-sharp rhythm machine. Their songs have defined the metal sound, and paved the way for countless imitators. Jamie Humphries provides a note-by-note guide to five Metallica favourites from across the band's career, including Battery , Sad But True and Enter Sandman .