In tango music, there’s an important concept called “la mugre,” literally, “dirt” or “grime,” but referring to a figurative scintilla of grit—a bit of rawness and emotion in both the music itself and the dancing. If your tango isn’t tinged with adequate mugre, explains violinist Jeremy Cohen of Local 6 (San Francisco, CA), it will lack the depth for which the genre is known.

Coming to tango a bit later in his musical life, adding it to his well-established repertoire of both classical and jazz music, Cohen found that the concept of mugre resonated well with him, giving a word to a feeling he’d had for quite some time—that a rigid culture of perfection tends to sanitize music itself. “The mugre is what gives the music its soul; that’s the good stuff,” he says. “You can’t fool anybody if you’re not coming from a place of real joy, and that means being able to play freely and without fear.”

That’s not, he is quick to clarify, to say that technique isn’t important. Having studied classical violin under legendary performer-pedagogues Itzhak Perlman and Anne Crowder, he puts strong value on knowing his way around a fiddle and a bow, but his circuitous route to serious studies included an extended stint in his grade school jazz band after a false start in the orchestra. “I was sitting with my legs crossed, so they sent me to the back. I didn’t like that, so I quit and joined the band instead,” he says. This was a minor infraction but one which stuck in the craw of the young Cohen, who found himself with a two-track career from the very beginning: studying classical music at Sonoma State in California with utmost seriousness while also playing casual swing gigs on the Russian River.

As his career developed, taking him the long way around from New York to Los Angeles via the road company of The Best Little Whorehouse in Texas, he eventually found his way back home to Northern California. Settling down in San Francisco, he pulled the parallel tracks closer together, performing with a number of prominent and diverse ensembles. Eventually, he formed his own Quartet San Francisco, an eclectic string quartet that explores the possibilities of string-forward contemporary music. Quartet San Francisco has won tango competitions, performed the music of everyone from Dave Brubeck to Michael Jackson, and snagged a handful of Grammy nominations in its nearly 20 years of existence. The quartet’s lack of self-imposed boundaries allows Cohen the freedom to explore genres and composers broadly, but also to take a deep dive into a single sub-genre or even an artist’s repertoire. “Really, we’re just expanding the roles of the modern string player; putting the strings front and center,” he says.

Cohen also heads up Violinjazz, a more straightforward does-what-it-says-on-the-tin jazz group, where he digs deep into the swing and big band violin repertoire, expanding beyond the better-known Joe Venuti and Stéphane Grappelli and into the work of Stuff Smith and Eddie South. Violinjazz is also the name of the Cohen’s publishing label, where he composes, arranges, and produces sheet music from the broader repertoire of American string music.

The freedom that comes from all of these outlets to simply play what he loves to play and create what he loves to create is a major key to Cohen’s success, he believes. He works to impart this joy and fearlessness to his own students, whom he primarily teaches via StringMasters, his custom-built online teaching platform. A few years back, Cohen found himself, like so many other teachers, frustrated trying to teach remote lessons via a patchwork of glitchy apps, juggling payment systems and video conferencing software, and emailing PDFs of sheet music. So, alongside a student who also worked as a web designer, Cohen built his own dream platform from scratch, giving him the flexibility to modify it for his own needs as a teacher, both in terms of real-time lesson capability and scheduling, payment, and other administrative necessities. Teachers can pop pieces of sheet music onto the screen from a massive library and mark it up in real time onscreen. Students can re-watch their recorded lessons at their leisure. Both can maintain an easy-to-manipulate personal library of sheet music and recordings. “It’s designed for serious musicians who want a higher lesson quality and the ease of just one platform,” Cohen says.

Though the StringMasters platform (www.StringMasters.com) predates COVID by a few years, it did come in awfully handy when Cohen, who also serves as the artistic director of string, and his fellow teachers all found themselves unable to teach lessons in person. Not only has the number of individual teachers using the platform skyrocketed, a number of prestigious summer programs used it this past summer as their instructional base. The dynamic system allows for constant improvement even now: Cohen is currently working to add instant video playback—the closest replica of playing duets currently possible with web capabilities.

Private instruction is what’s keeping most of Cohen’s time filled during the ongoing pandemic shutdown, but he credits the AFM with providing a career’s worth of job security leading up to this point. He rattles off his locals with the same jovial familiarity with which he rattles off old bandmates: “I was a member of 802 in New York, and then after I went to LA, I was a member of 47, and now I’m a member of [San Francisco Local] 6,” he says. He reminisces of a time when San Francisco was a die-hard union town and blue-collar and white-collar workers were ready to go to the mattresses on each others’ behalf whenever it was needed. Union-busting on a nationwide scale is a major factor, he believes, in the current political climate. “How many of these people out here have no backup?” he asks. “They just see things getting worse and worse; the destruction of the entire middle class in their lifetimes, but instead of protection, they got NAFTA.”

Even in a political climate that is hostile to organized labor, Cohen sees the way out as growth. “We not only have to survive [as a union], we have to figure out a way to come back bigger,” he says. “The path back means more than just survival; it means growing the base.” For him, though, that’s an easy sell, especially in a part of the country with a notoriously high cost of living. “Without a steady job in San Francisco, like with the symphony or the ballet or the opera, making a living—especially raising a family—without the auspices of union work is not possible.”