Rob, you can't live in denial forever!
But I accept that Scott Gorham and Brian Robertson didn't initially have the chops (or better: musical theory) to ape WA correctly!
Tony Visconti is on record for saying that even as late as Black Rose, Gary Moore would spend hours in the studio patiently showing Scott Gorham harmony leads to what Moore had come up with.
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" The next album 'Fighting' in 1975 saw Lizzy's style develop further with the harmonised guitar-lines of Gorham and Robertson backed up with power-chord rhythm work. As Scott recalls:
'Wishbone Ash had done the twin guitar thing before us, but we took the idea and put it into a hard rock context, with more aggression.' "
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https://books.google.de/books?id=60Jde3l7WNwC&pg=PA88&lpg=PA88&dq=Phil+Lynott+Wishbone+Ash&source=bl&ots=x6XizpUY-m&sig=ke9l-sqwCdvhlxiSr30eSr46OoU&hl=de&sa=X&ved=0ahUKEwiZ4Nu3ouPTAhWBULwKHdvcCYgQ6AEIVTAG#v=onepage&q=Phil%20Lynott%20Wishbone%20Ash&f=false***
"For more than 45 years, Wishbone Ash, in it’s many incarnations, has traveled the globe delivering music that blends equal parts blues and English Folk traditions while keeping itself firmly rooted in the Progressive Rock and psychedelic era from whence it came. The band’s distinctive twin lead guitar attack was an unplanned stroke of genius and this powerful melodic technique was borrowed and updated by countless bands including Thin Lizzy and Iron Maiden."
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"At this point, guitarist Eric Bell departed, feeling, after the hit with ‘Whiskey In The Jar’, that the band were becoming too commercial for his liking, and for the first of numerous occasions, Belfast born blues guitarist Gary Moore became a temporary replacement. Mr Moore and Mr Lynott were old buddies, Phil having briefly played in Moore’s band Skid Row in the late 1960s. Gary Moore remained until Lynott made what would be the decisive change for the band – he was replaced not by 1, but 2 guitarists, Brian Robertson from Glasgow and Californian Scott Gorham and thus arrived the famous twin-harmony guitar frontline, so much copied in later years, becoming a power-metal trademark. Gorham says the two guitarists clicked immediately but admits that there was no grand plan and the sound came about purely by accident. (While Lizzy’s twin-harmony guitar frontline was highly influential it was by no means their own creation, previously featuring in bands such as Fleetwood Mac and particularly, Wishbone Ash, though in retrospect, Lizzy seem to receive most of the credit – probably due to their commercial success)."
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