There’s not one guitarist who has had more influence on heavy metal than Black Sabbath’s Tony Iommi. Iommi, now 65, is the godfather of heavy metal as we know it today, impacting several generations of bands from Judas Priest to Metallica to Soundgarden to Slipknot. And it’s his killer riffs (his solos are stellar as well) that are Iommi’s trademark as he’s come up with some of the heaviest and intense chord progressions.

While there are so many outstanding riffs within the Black Sabbath catalogue, here are five of Iommi’s greatest riffs.

“Into the Void” on 1971’s Master of Reality

“Into the Void” at first might seem not to belong among the greatest Iommi riffs ever, but it’s an example of a hypnotic verse riff that grinds like no other that had come before it. It’s a perfect example of a riff that opened the door for other guitarist to emulate down the road and the riffs foreshadows the birth of doom and stoner metal. That doomy Iommi sound comes from his Gibson SG, old Laney amp and Rangemaster Treble Booster. Interestingly, Metallica’s James Hetfield lists “Into the Void” as his all-time fave Sabbath track.