An avid fan might guess that Metallica's landmark 1991 Black Album took some inspiration from AC/DC's classic Back in Black. But Metallica guitarist Kirk Hammett recently explained how the influence extended past the dark color that informs both albums.

Indeed, it was more so the success that accompanied the Australian rockers' 1980 album and its succession of straight-ahead hits that moved the Bay Area thrashers to set their sights on a sound outside of their breakneck metal origins. Along with Back in Black, Metallica were also moved by other big '80s albums.

"We didn't want to go down the same progressive, demanding route," Hammett tells Classic Rock of the period leading to The Black Album. "We had our sights set on bigger things. You have to remember that there had been some mega albums around that time — Bon Jovi, Def Leppard, Bruce Springsteen… eight million, nine million copies sold. And we wanted that. It's obvious. We wanted a Back in Black. "

Further, Metallica's AC/DC benchmark came at a time when Hammett's band was working together in a state of creative effortlessness, the musician recalled.

"The best parts of [The Black Album] kind of just wrote themselves," he continued of the self-titled effort now more identified by its color. "Solos and music and songs felt like they just appeared out of nowhere. It was like the universe handed it to us on a platter. Not like the first four albums."

In the same interview from Friday (Aug. 13), Hammett also discussed "Enter Sandman." Metallica devotees likely know the story of how Hammett came up with the memorable guitar part to the Black Album smash. But some may not recall it was inspired by Soundgarden.

"The 'Enter Sandman' riff was a riff that just fucking appeared," the guitarist shared. "It was 3 o'clock in the morning, I was sitting in my bedroom. People say, 'What were you doing up at 3 o'clock in the morning?' Well, I was still in tour mode. I was playing my guitar — I had nothing else to do. I'd been listening to Soundgarden all day; they were a band that me and James loved. I was just trying to capture that feel."

Perhaps Soundgarden were returning the black-inspired favor with 1994's "Black Hole Sun."

These days, Hammett recognizes that The Black Album is "a cultural force in itself. As much as modern culture changes and morphs, there's something within that album that continues to resonate around the world. And I mean the world, because it's big everywhere."

An expanded and remastered Black Album, plus a tribute collection of Black Album songs by other artists called The Metallica Blacklist, comes out on Sept. 10.

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