The iconic guitarist Kirk Hammett of Metallica has identified a groundbreaking guitar riff that he asserts significantly “transformed heavy metal.” In an insightful feature with Consequence, Hammett curated a list of 11 essential albums that he believes every guitarist should possess, due to their profound influence on his career. Notable mentions in his selection include Led Zeppelin’s Physical Graffiti, Van Halen’s self-titled debut album, Scorpions’ Taken by Force, and AC/DC’s Back in Black.

Among his selections, he highlighted a specific album by Black Sabbath, explaining how a particular riff from that album played a pivotal role in shaping the sound of heavy metal. Interestingly, it is not the ominous tritone famously played by Tony Iommi at the onset of the Black Sabbath title track.

“The first three albums by Black Sabbath are regarded as foundational texts. There is a widespread consensus that these records birthed the genre, culminating in a transformative sound with Vol. 4 and further evolving into Sabotage,” Hammett elaborated, emphasizing the band’s continuous innovation.

Delving deeper into the evolution of Black Sabbath, he described their performance on Sabotage as more progressive, advanced, and sophisticated than their earlier work. He specifically pointed out the riff from the track “Symptom of the Universe,” suggesting it encapsulates the essence of both the New Wave of British Heavy Metal and thrash metal.

READ MORE: Kirk Hammett from Metallica Identifies the Essential Album for Every Music Fan

“This song embodies a distinctive attitude, the selection of notes, the execution of the riff, and its role as a central hook within the song,” he continued. “Once you encounter that riff, it resonates in your mind repeatedly. It’s a phenomenal riff that fundamentally shifted the landscape of heavy metal, and I must acknowledge the significance of that album and song.”

Exploring Black Sabbath’s ‘Symptom of the Universe’

Unveiling Tony Iommi’s Creative Process Behind the ‘Symptom of the Universe’ Riff

In a revealing discussion with Metal Hammer a few years back, Tony Iommi shared insights into the creation of “Symptom of the Universe.” While he struggled to recall the exact moment of inspiration for the main riff, he speculated that it emerged during one of the band’s rehearsal sessions.

Nonetheless, he elaborated on his approach to riff creation, highlighting the evolution of his techniques over time.

“I was constantly competing with myself, striving to devise increasingly inventive ideas — experimenting with different tunings, adjusting the amplifiers, and essentially playing around with the guitars,” Iommi explained. “My focus was on self-improvement and innovation, steering clear of external influences to avoid inadvertently replicating someone else’s riff.”