"Yeah, music from all over the world," he says.
"It was really eye-opening for me because of all the different possibilities of music and the role that musicians take in societies."
Although The Epic was indeed epic, he felt its vastness was necessary for him. "I'd been making music for a long time at that point and most of what I'd been doing had been with other people. But I wanted to really document where I was at. I didn't know it was going to be three discs though," he laughs.
"I was trying to figure out how I could say it all on one disc and while I was thinking about taking a song or some songs out, I thought that 17 pieces was the expression of what I was trying to say at that time.
"I was having this dream that I had all those songs in it, and that affirmed to me I didn't need to reduce it. So I stopped trying to make it smaller and let it be what it is."
Though he's played alongside many jazz greats (Wayne Shorter, Kenny Burrell, Billy Higgins, Herbie Hancock), Washington is also a man of his generation and grew up on hip-hop in LA.
Which perhaps explain why he and his band are on the City Limits bill. He played on Kendrick Lamar's game-changing To Pimp a Butterfly of last year, and Lamar is the bill-topper on Saturday.
"Jazz and hip-hop are not isolated islands. Jazz has influenced and been influenced by other styles of music throughout its history. In the beginning it was influenced by blues and gospel and at the same time influenced blues and gospel. Then it was influenced by rock 'n' roll, boogaloo and funk in the 70s. And hip-hop.
"All those things are intertwined."
So jazzman Washington - who we might expect to join Lamar in a guest slot - is at home in this broader City Limits context, just as he would if he'd been invited to this weekend's Womad.
Kamasi Washington is a rare one, a jazz musician for all seasons.
Who: Saxophonist/composer Kamasi Washington, sometime sideman to Kendrick Lamar, Snoop Dogg, Flying Lotus, Chaka Khan and Thundercat.
Where: Auckland City Limits Festival, Western Springs Park, Saturday, playing 3.30pm on the V Energy stage 2.