Virtually every pianist of the last 50 years has been influenced in some way by Bud Powell–though relatively few of Powell’s contemporaries and only a handful of those that followed managed the balance of intensity and control that set his early recordings on fire. In fact, by the late 50s, when Hod O’Brien headed down from Massachusetts to New York, not even Powell could regularly summon the resources that had birthed his best music. O’Brien is one of the few pianists to come of age during Powell’s lifetime who has kept his style more or less free from the influence of later developments–modal and free jazz, fusion and world music, and shifting pop tastes. That may sound like willful artistic seclusion, but O’Brien, like his better-known contemporary Barry Harris, not only guards the integrity of Powell’s piano legacy but keeps the tradition fresh and lively. His melody lines are clean and uncluttered (though never simplistic) and his dense left-hand chords, which impart some of the shrouded mystery heard in Powell’s playing, are pierced but never completely dissipated by his sprightly improvisations in the upper registers. O’Brien–who’s put out two albums under his own name in the last five years as well as a couple with his vocalist wife, Stephanie Nakasian–rarely makes it to Chicago. Here he’ll work with bassist Kelly Sill and drummer Joel Spencer, who’ve played together for three decades. Friday and Saturday, February 7 and 8, 9 and 11 PM, and Sunday, February 9, 4, 8, and 10 PM, Jazz Showcase, 59 W. Grand; 312-670-2473.