Did you know that one of Kirk Hammett's most satisfying Metallica guitar solos was apparently the result of some tough love in the recording studio? Indeed, that's the case as the longtime Metallica guitarist laid it to Kerrang Tuesday (June 4). He told the mag he got the most personal contentment out of a solo in the band's subsequent live staple "The Unforgiven," forged by the playful ire of Black Album producer Bob Rock.

Asked which blistering axe run was "the most satisfying to actually create" in a Metallica track, Hammett recalled the story where Rock—also the St. Anger producer immortalized on film alongside the band's members in 2004's Some Kind of Monster—tersely goaded him into shredding.

"I was thinking about the solo in 'The Unforgiven,'" Hammett responded. "I remember showing up to the studio that morning, thinking I was going to play all these certain licks and then Bob Rock's going, 'That's fucking crap.' Then it was one of the very first times when I said, 'Just fucking hit the record button,' and shit flowed out. I prefer to record my solos that way now because I like the spontaneity of it; that's how that solo was pretty much created."

It's not the first time the Metallica member has talked about the producer's inspiring jab. In 2013, the guitarist said Rock requested "something dirtier and more sustaining—something more in the vein of Jeff Beck" in an interview with Guitar World. "At first I was kind of hurt," Hammett remembered, "but then I realized he was right."

Following its unique recording, Hammett's unintentionally effortless solo in "The Unforgiven" continued to get special attention from the musician. Three years ago, the guitarist told Classic Rock that it's "probably one of the only guitar solos that I play just like the album." Relive the pivotal Metallica Black Album song below.

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