Over the course of four decades, protofusion guitarist Larry Coryell has made some extraordinarily dynamic music, some extraordinarily unfocused music, and some music that managed to be both at once. But he's aged gracefully: playing songs from the Great American Songbook, folk-blues standards, and his jazz-rock originals, he brings a unique phrasing--brittle on the surface but substantive underneath--to the postbop guitar language he helped create. These days Coryell never sounds better than when he's accompanied by the local boys that make up his Chicago trio. Originally assembled as a pickup band for a Jazz Showcase appearance in the mid-90s, the group has become an open-ended forum for Coryell's rangy and omnivorous improvisations, with bassist Larry Gray controlling the centrifugal force that Coryell and drummer Paul Wertico occasionally generate. I love it when they get the old band together--even if the "old band" is more of a once-in-a-blue-moon gathering. See also Saturday and Sunday. a 9 and 11 PM, Jazz Showcase, 59 W. Grand, 312-670-2473, $25.