DESCRIPTION:
"The DADGAD tuning was used extensively by Jimmy Page of Led Zeppelin and The Yardbirds in the late '60s and '70s. While with The Yardbirds, Page recorded an instrumental entitled White Summer, itself inspired by the first recorded DADGAD tune, Davey Graham's arrangement of the traditional Irish tune 'She Moved Through the Fair'. On Led Zeppelin's eponymous first album, Led Zeppelin, he used this guitar tuning to perform "Black Mountain Side", though he detuned the entire guitar by one-half a step for the recording, so it was really D?-A?-D?-G?-A?-D? (where the '?' denotes a flattened note)--the piece which was strongly influenced by Bert Jansch's earlier arrangement of a traditional Irish song called "Blackwater Side" (though Jansch actually used 'drop D' tuning). Page later revisited the DADGAD tuning for the song "Kashmir", which appeared on the band's sixth album Physical Graffiti." - I copied and pasted this info straight from a great website on altered tunings called "Guitar Tunings Data Base" (GTDB) Hopefully this will settle some of the controversy surrounding this video, and all of the comments below.