IYKYK—that’s digital shorthand for “if you know, you know”—is a pretty perfect descriptor for one of the greatest, and certainly most slept-on, producers in hip-hop history: J Dilla. It’s not that the late Detroit beatmaker/rapper/singer (born James Yancey, and sometimes known as Jay Dee) isn’t celebrated—since his 2006 death due to complications from a rare blood disease, his 7 February birthday has been marked by parties around the world. Icons in hip-hop (Kanye West), R&B (Erykah Badu), electronic (Flying Lotus) and jazz (Jason Moran) call him one of the GOATs, and a key influence. But his commercial success was limited: He scored remixes and beloved deep cuts with Janet Jackson, Busta Rhymes and Ghostface Killah, but aside from Common’s 2000 track “The Light”, he never had a breakout radio hit or wide name recognition, partly because he had much of his initial successes as part of larger collectives with bigger names (The Ummah and Soulquarians). But almost 20 years later, if you know where to listen, you’ll hear his influence everywhere: from KAYTRANADA to Anderson .Paak, Robert Glasper to Kendrick Lamar to the “study beats” you’ll hear playing tastefully in the background at your local coffee shop. With his truly revolutionary use of sequencers and samples (later mixed in with live instruments), he invented a new rhythmic vocabulary, where swung hi-hats meet rushed snares meet behind-the-beat bass. Once you recognise his signature rhythmic lope, you’ll hear it everywhere. Dilla Time, an aptly titled book by Dan Charnas, makes the case for Dilla’s genius. “The argument I'm trying is that Dilla literally created a third path in rhythm,” Charnas tells Apple Music. “There’s straight time—counted evenly, in the European tradition. Then there’s swing time, and that's the African American tradition. Then Dilla collided those two.” Here, Charnas picks five of Dilla’s most impactful tracks and explains what makes them so special. “I Don't Know”, Slum Village “I can't say enough about this song as an entryway to the genius of Jay Dee. 'I Don't Know' is from the first album [1996’s Fan-Tas-Tic, Vol. 1] by Slum Village, Jay Dee's group in Detroit. It was [initially] a self-release—they just printed out the labels at Kinko's, and dubbed the cassettes by hand. Q-Tip introduced him to everybody: De La Soul, Busta Rhymes, Mad Skillz, The Pharcyde. And the first record he produced that comes out is ‘Runnin’ by The Pharcyde, which has this very different rhythmic feel. It's loose, rolling. One of the techniques he used was to essentially not use the timing functions of his drum machines [i.e., quantising] as intended, which was very unusual in hip-hop. He was enthralled with this idea of error. But 'I Don't Know' is the debut of another technique called deceleration. It’s like playing a record at 45 RPM and then you slow it down. All the human errors of the musicians expand. [Dilla] would decelerate samples to reveal error—that's what he did with 'É Isso Aí' [by guitarist Baden Powell], this fast-tempo Brazilian song. He took this little piece, slowed it down to half its speed, and suddenly those interesting errors in timing come out.” “Fall in Love”, Slum Village “This is the Jay Dee national anthem: When you hear it, you stand up straight, you put your hand over your heart. It's got this crazy little line in the middle of it that Dilla sang: 'Don't sell yourself to fall in love with the things you do.' Everybody sings it, but I don't know that anybody knows what it means. People put whatever they want onto Dilla because he didn't speak much. It could mean, 'Hey, the rap game is f****d up. Don't give yourself away to it.' Or it could mean, 'Don't change yourself for the world,' which is one aspect of what Dilla was. But it could also mean, 'Always change it up,' which is what he did. And again, in this song you have that deceleration technique, taking a Gap Mangione song 'Diana in the Autumn Wind', slowing it down and revealing the error of the bass notes against those snares. It really is the prototypical Jay Dee beat.” “Pause” “We talked about not quantising, playing freehand. We talked about deceleration. But then here is one of the greatest uses of Dilla’s third technique, which is to me the most important: displacement. That’s how he arrived at this jerky feel. The MPC3000 [sampler and sequencer] allows users to do something that Dilla’s other drum machine, the SP-1200, did not. Both have something called the swing function, which makes beats uneven. But the MPC allowed the user to swing and displace individual elements independently of all the other elements. You could swing the snare, but not the kick. You could swing the hi-hats a little, and swing the snare a lot. You hear it in 'Pause', in the rushed snare that comes way too early that clashes with the straightness of the hi-hat. It's like a train that's derailing and righting itself over and over again. It’s drunken, limping, loping, whatever you want to call it. But it's not sloppy—it’s intentional.” “Waves” “Dilla creates ‘Waves’ as part of this little beat tape that he made for [DJ and Stones Throw label founder] Peanut Butter Wolf called Donuts. He was beginning to use laptops to stretch samples out rather than just slow them down. It was a new kind of digital manipulation. In this particular record he's sampling a song by [English rock band] 10cc with the words 'Johnny, don't do it', but he edits the word 'don't' out so it's 'Johnny, do it'. This becomes very significant about a year later, after he dies, when his younger brother John hears it. Donuts has just come out, and Johnny’s listening to it for the first time as he's driving to Detroit to be with his family. He hears his brother calling out to him: 'Johnny… Johnny...' All the fandom around Dilla that emerged after he died, all of that energy glommed onto Donuts, because that was the last testament. 'Oh, he made it in the hospital.' He didn’t! The first iteration of Donuts he did after he emerged from the hospital in March 2005. So this song not only represents that moment in his time, but it also represents the kind of projection that we engage in as fans.” “Won't Do” “We have tended to focus on Donuts as his last will and testament, but that's actually not true either, because he didn't put really any effort into Donuts. It was just a beat tape. The thing that he was spending countless hours in the studio on was this album that became The Shining. 'Won't Do' is everything about James rolled into one. It's an incredible piece of beatmaking. It is an incredible piece of mixing—it's a beautiful-sounding record and it contains one of his most fire verses of all. It also showcases him as a singer. And it's him as the artist; he’s not producing for anybody. So 'Won't Do', to me, is like, that's who he became, and that's the artist who would've evolved from that point.”