Jerry Jeff Walker has often misplaced his vocal and musical instincts recently, but when he finds them he can still put on an inspiring show that mines that territory where country and folk music overlap.

He put on just such a show at the Birchmere Saturday night with no more accompaniment than his own acoustic guitar. His voice was in fine shape; it moved with agility from grainy, whispered confessions to ringing, boasting shouts. His instincts were sound, too; he turned every song into a story that soon had the listener walking down the highways and back streets with the singer. He embroidered his well-known stories with parenthetical comments and introductory monologues. Thus he gave ballads like "Morning to Sally" a vulnerable tenderness that silenced the sold-out bar.

A Colorado quartet played an opening set in two different guises. First they appeared in suits and ties as Hot Rize, a bluegrass band locked into the timeworn formulas of the genre. They were all competent players, but never exceptional. They then changed into cowboy hats and shades and reappeared as Red Knuckles & The Trailblazers, an old-fashioned country-western band. In this more comic role, the foursome played with a looseness and a spirit that made their honky-tonk and western swing numbers more enjoyable than their bluegrass picking.