J. Blackfoot is considered a blues celebrity on the chitlins circuit, but he has yet to cross over into the white market--probably because that market too often insists on defining singers like Blackfoot as "soul" rather than "blues" artists. Blackfoot, whose real name is John Colbert, first attained recognition as the lead male singer of the Soul Children, a lesser-known but potent aggregation that charted some important singles on Stax in the late 60s and early 70s. In 1983 he struck pay dirt on his own with "Taxi"--one of the most eloquent R & B ballads of that decade. Since then he's had a small but steady stream of hits (including the lovely "Just One Life Time" from the early 90s, still one of the most requested songs on contemporary blues radio). Blackfoot's stage show is among the tightest around: his backup singers are impeccably choreographed, his band cooks in a powerful soul-blues-funk groove, and Blackfoot himself achieves an effortless blend of down-and-dirty funk, sweaty R & B showmanship, and seductive romantic intimacy. Saturday and Sunday, 8 and 11 PM, Tyrone Davis Entertainment Center, 1744 N. Central; 637-3699.