Though they haven’t received half the press, the Montzkas would come second only to Von and George Freeman in a Chicago jazz-sibling rivalry. When keyboardist Karl locks rhythms with drummer Eric, they make a great case for nature and nurture: having grown up in the same household, presumably listening to much of the same music, they share a prickly sharp approach to the beat. At times they threaten to create a feedback loop, as their dead-center accents reinforce each other and intensify; but the brothers also share a fine sense of balance, and can easily skate back from the brink. Karl brings an attractive aura of abandon to the piano, but it turns into something really special when he plays the Hammond B-3 organ, as he does in this group. As he joined his brother behind the saxophonist Rudresh Mahanthappa a couple months ago, the spirit of Larry Young hovered close, but at moments so did the specter of Jimi Hendrix, and the stainless-steel funk that Joe Zawinul briefly brought to the instrument popped in as well. Karl doesn’t use the B-3’s foot-pedal bass notes; instead, his left hand becomes the quartet’s bassist, playing the lower keys on the instrument’s bottom manual. What he loses in terms of two-handed chording, he makes up for in contrapuntal complexity and a sort of guerrilla style–lean, edgy, and extremely motile, it packs a wallop, with few of the plush swells other players eventually arrive at. He rounds out his quartet with Eric; the electric and poetic guitarist John Moulder; and bass trumpeter Ryan Shultz, whose long-lined solos provide a welcome shot of unplugged melodicism. Since weekend nights at the city’s liveliest jazz hangout have gotten steadily noisier, arrive early if you actually want to hear the music. Friday, 9 PM, Green Mill, 4802 N. Broadway; 773-878-5552. NEIL TESSER

Art accompanying story in printed newspaper (not available in this archive): uncredited photo.