CAMBRIDGE, Mass. — At age 75, drumming legend Max Roach continues to seek adventure instead of convention.

Such is the case with the Beijing Trio, in which he is joined by Jon Jang on piano and Jiebing Chen on the erhu, a two-stringed Chinese violin.

Formed two years ago, the group performs infrequently but brought its delicate balancing act to the Regattabar on Thursday for the opening of a three-night stand.

"This is way looser than anything I've heard Max play," said fan Andrew Jones, 33, of Boston, who was more familiar with Roach's bebop history. "It's fairly free, but very brave."

The group's 55-minute, mostly improvised first set showcased the attentive nature of the musicians, yet seemed like a tasty appetizer more than a main course.

Sitting gingerly at a four-piece kit, Roach set the tone with a cycling pulse of stick-to-stick rim-shots to his snare and etched accents around the drums that ended with the undulating pitch of a pedal-controlled floor tom.

His stop-and-start pacing and sense of space paved the way for fleeting initial statements from his bandmates.

Chen, a native of Shanghai who plays the erhu with symphony orchestras and San Francisco Bay Area jazz players, injected a breath of fresh air. Gliding her bow between the strings of the erhu, which she played upright, with its snakeskin-covered resonator on her lap, she sustained notes both sweet and soulful.

Bay Area compatriot Jang was more hesitant during the first two of the set's five pieces, his scampering tradeoffs with the cymbal-crashing Roach leaving Chen to carve out sparse melodies.

Jang took the lead on the third piece, shifting from stately to gently cascading ornamentations, which introduced more of an Eastern flavor, before he trilled his notes into "Amazing Grace."

Roach surged into accents, clacking a stick within his kit's hardware and developing cymbal-crashing momentum that pushed Jang to break more loosely from the form of the tune until the pianist asserted himself with robust chords.

But the trio soon returned to familiar territory, as if the set was a suite, its theme served by Roach's brief, broken-pulse interludes, which either closed or launched most pieces.

With a more thoughtful than physical approach to his kit, he didn't swing on ride cymbal until the fourth improvisation, giving Chen room to fly a bit with bowed flurries and even slide her fingers on the strings for a whistling effect.

By the last piece, she more comfortably referenced jazz and Chinese melodies within the group's rustic sketches.

Weston resident Katherine Gogel, 39, who grew up in Asia, said she found a Chinese essence in the music.

"I got visions of Chinese theater, where each tone with [Chen's] instrument seemed like a voice, and his drums seemed like movements," Gogel said. "Chinese theater is a bit jerky. All of a sudden, there's crash, crash, and then, silence."