Swiss pianist Irene Schweizer stands out in the free-jazz milieu for many reasons, but her gender is certainly one of them. In the mid-60s, inspired by Ornette Coleman and South Africa's Blue Notes, she immersed herself in the brawny European free-music scene that included Peter Kowald, Peter Brštzmann, Evan Parker, and Han Bennink, and not until a decade later did she team up with other women--including reedist Lindsay Cooper and vocalists Maggie Nichols and Sally Potter--in the Feminist Improvising Group, which evolved into the European Women's Improvising Group in 1983. Yet though Schweizer has said that the predominance of testosterone in those early days occasionally caused her to play more aggressively than she would've liked, she never managed even then to mask her distinct musical personality: her love of Cecil Taylor may have been evident in her furiously dissonant runs and angular phrasing, for instance, but it never affected her melodic acuity or hindered her light touch on the keys. For the past decade, her preferred performance modes have been duos with drummers (Bennink, Andrew Cyrille, Pierre Favre, Louis Moholo, Mani Neumeier, and GŸnter Sommer among them), her trio Les Diaboliques with Nichols and bassist Joelle Leandre, and solo--which is how she'll perform in this rare Chicago appearance. In all of these formats, she's pared her playing to its lyrical essence, and her definition of "freedom" has little to do with brute expressionism and everything to do with lithe spontaneity. On her most recent solo outing, Many and One Direction (Intakt), her complex lines are largely uncluttered by superfluous rhythmic comping; she uses her left hand more for subtle punctuation than propulsion. In more delicate moments, she evokes Erik Satie, but her music is never so sheerly fragile as his. The singsongy melodies of "HŸben wie DrŸben," for example, are pushed along by forceful execution, while her take on Carla Bley's pretty "Ictus" is lean and precise. Her dedication to Don Cherry, "Jungle Beats," echoes the trumpeter's famous duo with drummer Ed Blackwell by juggling boogie-woogie patterns and South African highlife melodies with various densities, rhythms, and tempos--serving as both melodist and percussionist, she explores each combination for five thrilling minutes. She also does well when she abandons the keyboard altogether, reaching inside of the piano to scrape and thwack out grooves with obvious glee. But as her lovely take on Thelonious Monk's "Chordially" asserts at the album's conclusion, she's a jazzwoman at heart. Wednesday, 10 PM, Empty Bottle, 1035 N. Western; 773-276-3600.