For some music fans coming of age in 1994, the release of Tortoise’s debut album that year was something of a watershed moment. The Chicago instrumentalist collective’s heady blend of disjointed time signatures, atmospheric grooves and skeletal production sounded like nothing else. Being released on the then hip upstart indie label Thrill Jockey brought the music to an alternative rock audience that normally might not have been aware of such esoteric sounds.

While grey-bearded veteran music aficionados familiar with free jazz, dub and krautrock would have certainly found a lot to like, for pimply teens and 20-something Gen-Xers mired down in Mudhoney and Soundgarden, it was like an extraterrestrial transmission from some distant sonic solar system.

More than a quarter of a century and a few lineup changes later, the post-rock pioneers are still out there. An upcoming three-day stint at Blue Note Tokyo will see the group playing two sets each day. During the first set, the band will perform its highly-regarded third (and jazziest) album, “TNT,” from start to finish. The second set has cheekily been titled “Greatest Hits.”

Bassist and founding member Douglas McCombs says the shows are quite involved.

“2018 was the 20th anniversary of the release of ‘TNT’ and different promoters began asking us to perform the album in its entirety,” he says. “We normally are not interested in doing things like this, but we thought this would be an opportunity to perform the songs the way they are arranged on the album. We’ll have six additional musicians with us for these performances.”

For such a renowned band, Tortoise has a rather tricky discography to navigate. Technically, there are seven albums under the group’s wing. But a number or remix projects, collaborative outings and one massive boxed set make for an impressive and imposing body of work. Asked if there any records he would like to do over, McCombs opts for one of Tortoise’s best-loved albums, “Millions Now Living Will Never Die” from 1996.

“I am pretty satisfied with most of our albums,” he says. “(But) there are some songs on ‘Millions Now Living Will Never Die’ that I wish we had performed better and maybe spent a little more time on.”

Tortoise’s most recent album, 2016’s “The Catastrophist,” pushes the band’s legacy further, continually making avant-garde ideas accessible. “Shake Hands With Danger” is a bracing metallic death march, while “The Clearing Fills” is an unapologetically soothing piano-driven lullaby. “Rock On,” meanwhile, is a spacey and surprisingly successful cover of the David Essex 1973 glam classic. There are even guest vocals, a rarity on a Tortoise album, with Yo La Tengo drummer Georgia Hubley breathing some delicate chanteuse magic into the lovely “Yonder Blue.”

“We did not write ‘Yonder Blue’ with Georgia in mind, but as the song developed we knew it should have singing,” McCombs says. “Georgia is a longtime friend and we knew she would do something interesting.”

Along with its trademark sound, one of the band’s defining characteristics is its deep connection to the city of Chicago. Over the years, many members have been associated with iconic local acts, including The Sea and Cake, Eleventh Dream Day and Poster Children. They are as much a part of the metropolis’ legacy as Muddy Waters, Cheap Trick or Kanye West, and the influence of the Windy City’s free jazz, noise rock and hardcore scenes can often be heard zigzagging throughout the band’s music.

“Chicago is where we formed and have done most of our work,” McCombs says. “It’s an important city for 20th-century music and we have always been aware that that history informed our music in some ambiguous way. Now we’re spread all over the U.S. and that is affecting our music also. We have felt more like an international entity as the years go by and as the internet expands available knowledge.”

Knowing the Tortoise experience would be lacking without digging deeper into the band’s numerous side projects. Quirkiest may be their complete recreation of Greek new age guru Yanni’s “Live at the Acropolis.” Recorded with Beck and Sonic Youth’s Thurston Moore, it walks a fine line between sincere inspiration and an outright madhouse mockery. The group’s backing on the album “The Brave and the Bold” by freak folk icon Will Oldham (aka Bonnie “Prince” Billy”) is another bizarre and worthwhile pit stop. Fleshing out Oldham’s usual sparse sound, the musicians tackle and transform 1970s tracks by Bruce Springsteen, Elton John and Devo.

Asked about his early influences, though, McCombs says it was all punk rock to start with.

“When I was forming my opinions about music it was during ’70s punk, so it was Television, Wire, Talking Heads, X and Devo,” he says. “Something more analogous to Tortoise might be (experimental English post-punk trio) This Heat.”

Hot off the success of “Millions Now Living Will Never Die” in the mid-’90s, Tortoise toured Japan and incrementally made some notable musical links. The band’s moody remix of Cincinnati, Ohio, hip-hop crew Five Deez’s “Sexual for Elizabeth” sports the distorted proto-mumble rap skills of Tokyo’s Shingo Annen, better known as Shing02. Of equal attention is Japanese musician Nobukazu Takemura’s soft, stylish, remix of the title track from the “TNT” album.

“Coming to Japan for the first time in ’96 was something most of us had thought about since we started playing in bands,” McCombs says. “I think it was because we perceived the culture as something vastly different and (more) interesting (than) the American and European experiences we were used to. We have been lucky over the years to have had such great audiences and to connect with so many like-minded people. Some of our best performances have happened in Japan.”

A group that works as a collective as well as allowing its individual brethren to step out, Tortoise members spread themselves far and wide. Drummer and founding member John McEntire has produced or engineered albums for the likes of Bright Eyes, Broken Social Scene and Teenage Fanclub. Guitarist Jeff Parker has scored a number of underground films as well as releasing what may be one the first great albums of the 2020s: the unpretentious and soul-searching “Suite for Max Brown.” One of McCombs’ other bands, Brokeback, is a revolving collective of likeminded musicians that paint earthier, more organic soundscapes than Tortoise.

The impact that Tortoise’s debut album had on a generation of music lovers cannot be denied. It was a dirty, secret gateway drug to more glorious and dangerous sounds. You do not get deep into Albert Ayler, Yoko Ono and Karlheinz Stockhausen over night. But that first Tortoise disc showed the way to infinite possibilities.

In an era where often artists come off as pedestrian by trying too hard to be weird, remember that 1994 Tortoise album and feel the love, as McCombs himself does.

“We had no idea what people would think of our first album. We knew we wanted to make something familiar, but different, that would be very personal to who we are as musicians,” he says. “It’s gratifying that people were able to pick up on that.”

Tortoise will perform at Blue Note Tokyo in Minato Ward from Feb. 9 to 11, playing two different sets each day. For more information, visit www.thrilljockey.com/artists/tortoise.

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