With flowing instrumental passages, song lengths that baffled radio DJs and lyricism inspired by Hindu scripture, Yes defied rock 'n' roll even while finding success within it.
The defining band of the progressive rock genre will be inducted into the Rock and Roll Hall of Fame on April 7 -- and co-founder Jon Anderson credits Yes with holding firm to principles.
"Music shouldn't just be a commodity. It's about evolving as a musician and a group of musicians," Anderson told AFP by telephone.
"And that's what Yes did. It stayed true to its ideal," he said. "It's great when a band sticks to an ideal -- sometimes you're famous and sometimes you're not."
Led by Anderson's distinctive countertenor voice, Yes took more inspiration from the structure of steady-building classical symphonies than the quick-paced power of R&B that is at the root of so much rock.
Yes, which has sold more than 50 million records, nonetheless had its only number-one song in the United States with a more traditionally structured pop tune, 1983's "Owner of a Lonely Heart."
The English band will next year celebrate its 50th anniversary after a slew of personnel changes that have left its lineup unrecognizable from the original.
Bassist Chris Squire, who founded Yes with Anderson, died in 2015 after being diagnosed with a rare form of leukemia.
Longtime Yes keyboardist Rick Wakeman was especially upset that Yes is finally entering the Rock and Roll Hall of Fame after Squire's death but agreed to attend the ceremony in New York after an agreement to honor Squire's widow.
"I think Chris will be there in spirit, but bless him," said Anderson, 72, who tours with Wakeman and former Yes guitarist Trevor Rabin as ARW.
- 'We're all spiritual' -
Anderson has long incorporated meditation into his daily life and frequently brings themes of nature and environmental protection into his lyrics, such as on the 1978 song "Don't Kill the Whale."
Asked about his rituals, the singer said meditation was not a fixed activity.
"It depends on how you look at meditation. Walking around the garden or walking around the city, you can meditate by being part of the whole energy that surrounds you," he said.
Anderson said he often wondered why he and not others have had so much success and believed it was because of his focus on "this divine energy that surrounds us all the time."
"From the first few songs I wrote on the first album, I'm still singing about the same things," he said.
"People say, 'Oh, you're very spiritual.' I just say, 'No, no, we're all spiritual. I just like to sing about it,'" he said with a laugh.
The ambitions of Yes came into stark focus in 1973 with its album "Tales from Topographic Oceans," consisting of four tracks of around 20 minutes each.
Anderson wrote the concept around four Hindu shastras, or scriptures, he read in Paramahansa Yogananda's classic book "Autobiography of a Yogi."
Friction over the length of the album, which covered four sides of vinyl in an era before CDs and the internet, prompted Wakeman to leave Yes for a time.
- Excited for future -
Outside of Yes, Anderson has embarked on diverse projects that include ambient music for meditation, an exploration of West African music and an album on a Native American legend of a people living across different cultures and centuries.
Anderson said his upcoming ideas include a musical take on Rumi, the celebrated 13th-century Persian poet whose writings he called beautiful yet clear.
More unexpectedly, Anderson volunteered that he was a fan of "La La Land," the Hollywood musical revival. He said his daughter suggested he see it and the prog rock veteran became convinced that "La La Land" broke the mould in its own way.
Mentioning he has three large screens in his home studio in California, Anderson said he was looking to test the impact on music of new technologies from virtual reality to surround sound.
"I'm working on so many things it would drive you crazy to even understand," he said with a laugh.
"I'm in my 70s and I'm still enjoying what I do."