Judging by the small turnout at the Equestrian Center in Upper Marlboro Saturday, the annual "Blues Bash" is still one of the area's best-kept secrets. The festival, which ran from midafternoon till nearly 2 the next morning, featured dozens of country and urban blues musicians, including headliners Jimmy Witherspoon, Johnny Copeland and Elvin Bishop.

If anyone thought Witherspoon's weathered baritone and slow, deliberate phrasing might be overshadowed at a concert that featured a preponderance of searing guitars and harmonicas, he was flat wrong. Backed by the Uptown Rhythm Kings, a local band that sports a fine horn section, Witherspoon immediately established a strong, persuasive mood with "Stormy Monday" and maintained it for the entire show.

Guitarist Copeland could have used some horns -- he usually records with them. But he was in fine form nevertheless, and charged through a blistering set of Texas blues. In fact, he was so animated on stage that he brought to mind fellow Texan Albert Collins, who's well known for stretching the limits of his guitar cord.

As for Bishop, he knew exactly what the festival was all about. He overlooked his own rock hits of a decade ago in favor of some vibrant blues workouts that recalled his years with the Paul Butterfield band. He also clearly got a kick out of working with the Nighthawks and the remarkable boogie pianist Pinetop Perkins, a veteran of the Muddy Waters band. (Earlier, harmonica wiz Jerry Portnoy, another Waters alumnus, debuted a promising band of his own called the Sidewinders.) Along the way, the Nighthawks delivered a rollicking set of their own, with Jim Solberg, formerly of the Luther Allison band, playing exceptional lead guitar.

In addition to the Uptown Rhythm Kings, the show benefited from an assortment of other area acts and personalities, including Ben Andrews, Bowling Green John Cephas, Phil Wiggins, Tom Larsen, Nap Turner, Archie Edwards, Barry Lee Pearson, Lil' Jr. and the Hitmen and Jerry (Bama) Washington. The unexplained absence of women performers, however, seriously compromised the programming.