Jimmy Page shared a sample of the rare song "Rock & Ruin," marking the 40th anniversary of his XYZ sessions with then-former Yes members Chris Squire and Alan White.

Although the Led Zeppelin guitarist didn't comment on its evolution, the 1981 track bears a strong resemblance to another leaked song that later morphed into "Fortune Hunter" by Page's '80s supergroup the Firm. You can stream the snippet of "Rock & Ruin" on Page's website.

The guitarist briefly detailed the XYZ sessions there and on Facebook, writing, "On this day in 1981, I played the XYZ sessions at the Sol. The first playing I did after Led Zeppelin split up was with Chris Squire and Alan White — the rhythm section of Yes. They got in contact and said they had some material, and I said I had a studio. This was the best medicine I could have had at this time, and I knew that playing with them might be quite challenging, knowing the quality and precision of the music they had established with Yes."

Page continued: "In fact, the combination of the three of us proved to be substantial. Chris had supplied bass, piano and vocals, with Alan on backing vocals and drums. Chris even had a name for the outfit — XYZ [Ex Yes and Zeppelin], and I believe they hoped Robert Plant would have a listen, but I think he was occupied. And the party was over. However, the music that was done at this point was really good."

He called "Rock & Ruin" a "rough mix of something I presented to them," adding that "their songs were more impressive." XYZ worked on material at Squire's home studio, also recruiting Greenslade keyboardist Dave Lawson. Squire sang lead on the recordings, and as Page alluded, Plant passed on fronting the project. ("[He] came and listened to our music; he thought it was complicated," Squire told Noise11.com in 2012.)

Unofficial, low-fidelity demos of the sessions have been available for years on YouTube. These include what sounds like "Rock & Ruin," another instrumental (later reworked as "Mind Drive" for Yes' 1997 LP, Keys to Ascension 2) and two vocal-based songs (one that evolved into "Can You Imagine" from Yes' 2001 LP, Magnification; another that developed from Yes' "Song No. 4 [Satellite]," a Drama outtake released on that record's 2004 CD reissue).

In an October Rolling Stone interview, Page looked back on the XYZ demos, including "Rock & Ruin."

"I went in there, and we did some of the songs that they’d already worked on, and then I came up with my guitar parts for these things, and that was really interesting," he said. "And Chris was singing on them. I thought, 'I’ve really had to concentrate,' because it’s things in different time signatures. I mean it was a serious workout. But it was great. It was brilliant. And then I said, 'I’ve got one,' and I played them what actually becomes 'Fortune Hunter' with the Firm."

He described the song as having "a totally different sort of onset when it was done with Chris ... more like a guitar instrumental with Chris and I."

Page also added that "it's all speculation" whether the XYZ tapes will ever see official release.

"Unfortunately, we’ve lost [Yes bassist] Chris now," he said. "It was something that I always hoped to do, as some sort of project, to get hold of him and Alan White. It’s not even worth talking about, because it’s all speculation. I haven’t had a chance to really listen to the stuff and see just exactly what we do have, and what we don’t have. I don’t have any mixdowns of it. If I did, I’m not quite sure where they are now."


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