Boston Globe, February 24, 2008

In the Japanese tradition, the ronin is the masterless samurai. The consummate free agent, he rejects conventional authority and moves through the world with defiance and dignity.

In jazz today, Ronin designates something no less rigorous and idiosyncratic. It’s the name that Swiss pianist Nik Bartsch chose for his quintet, a one-of-a-kind unit that performs what Bartsch calls Zen-funk – a cerebral music influenced by minimalism, yet blessed with head-nodding, foot-tapping rhythmic tendencies, and an exhilarating sense of pacing that makes each composition a fascinating adventure.

The group visits Regattabar on Thursday in support of its new album on the prestigious ECM label, “Holon.” It’s the first full-fledged US tour for Bartsch, 36, who has been steadily developing his concepts for many years but was virtually unknown outside certain Swiss and German circles until hooking up with ECM two albums ago.

At first, Ronin was a trio, with Bartsch’s childhood friend Kaspar Rast on drums and a Swedish bassist, Bjorn Meyer. But the sound fleshed out when they added a hand percussionist, Andi Pupato, as well as the reed player Stefan Haslebacher, who goes by the name Sha, and whose mournful, floating lines on bass and contrabass clarinets add an ethereal melodic dimension to an otherwise highly percussive lineup.

“Now with the quintet we have the capacity to create sound combinations in an almost classical sense of interpretation,” Bartsch says on the phone from Zurich. Among the influences he cites in the course of an hour-long conversation are Bartok, Stravinsky, and contemporary classical composers, in addition to James Brown, the Meters, the Neville Brothers, and Prince.

What all these seemingly disparate sources have to do with one another, in Bartsch’s view, is the way they explore the tensions between less-is-more clarity of composition and the in-the-moment energy of performance. Two words that Bartsch uses a lot are “roughness,” meaning the raw friction of performed sound, and “dramaturgy,” or a preoccupation with moving the story forward: “It’s important to me what happens in a piece, in a whole record, over a whole evening,” he says.

Zen and funk, the two conceptual touchstones of Bartsch’s work, might appear to be polar opposites – the one clean, the other dirty, in an artistic sense of the term – but Bartsch sees it differently.

“Maybe Zen is clear, but it isn’t clean,” he says. “In the martial arts, the visual arts, the writing, there is roughness. And in funk too, there is discipline in group playing. The lifestyle is very different, but in the aspect of ritualistic groove, there is also this combination of structure and roughness.”

This creative dynamic has fascinated Bartsch since his early teens, when he saw the great Akira Kurosawa movie “Ran” and found himself fascinated by the warrior’s code, despite his own pacifist politics.

“I was in the anti-military movement,” he says. “And `Ran’ is a battle film, but I liked it very much. It was the first time that I saw this tension, the connection between art and emptiness and a warrior roughness at the same time.”

Only later did Bartsch, who learned to play jazz by ear well before catching up with classical training, discover the minimalists and the contemporary-classical scene. The impulse to compose by stripping elements away fit easily with his Japanese fascination, which by then had expanded to Zen practice, literature, and aikido. The ingredients came together as he decided his direction as an artist.

“I asked myself, what is my affinity?” he says. “Where do I want to say something, create a resonance that is authentic and honest? Who are the people around me with whom I want to play?”

The outcome, he says, was to shed work: “I stopped doing a lot of projects.” In their place, he started a band called Mobile, with which he began performing experiments that stretched the conventional limits of performance – for instance, playing nonstop for three days straight.

In late-1990s Zurich, the practice was a retort, and in some ways a parallel, to the techno-driven, rave-oriented underground dance scene. “I wanted to create an alternative to this fast club space,” Bartsch says. “To find out how a group can play together and keep this tension for such a long time.”

With their interlocking rhythms, odd-meter pacing, and melodic surges and sallies, the compositions on “Holon” – which, like all Ronin pieces, are referred to as “modules” and don’t have names, only numbers – encapsulate the accumulated experience of Bartsch and his bandmates. There’s also the added benefit of the famously crystalline production values of ECM and its founder, Manfred Eicher.

And as striking as the group’s first ECM effort, “Stoa,” was, “Holon” feels more subtle and complete, with fewer transitions that sound deliberately jarring and more space for pure emotional development. Bartsch has described the effect he seeks in his passages as similar to that of a school of fish that seems to move frenetically one moment, then surrender to complete calm. And upon listening, the image proves apt.

The group’s live performance promises to be nothing demure. Bartsch’s ideal stage setup places drum equipment within reach of all the musicians; he keeps a snare drum by his piano and also favors directly percussive playing of the piano’s strings.

The band draws inspiration from the live performances of the great funk bands – “I’ve studied Prince’s concerts a lot,” Bartsch says, “especially his funk concerts, after the regular shows” – as well as from various folk traditions that different members of the band have studied.

The result is one of the more striking combinations of heat and coolness on the musical landscape today.

“It’s a groove music that creates its own dramaturgical flow,” Bartsch says, and in the way Ronin balances emotion and formalism, one may just recognize the honor-bound rebellion of its namesake masterless samurai.