The 28th installment of the festival opens with a free concert at the Embarcadero’s Justin Herman Plaza, and moves to the Great Meadow at nearby Fort Mason for the main festivities the next day.

The music plays from 11 a.m. to 6 p.m. on the 23rd and 24th, and both days are headlined by native-son blues giants.

San Francisco blues legend Joe Louis Walker caps the Saturday set, taking the stage with the New Blues Allstars featuring Billy Branch, Ronnie Baker Brooks, Alvin Youngblood Hart and Kenny “Blues Boss” Wayne.

The eclectic lineup preceding Walker includes acoustic blues artist Keb’ Mo’, Shemekia Copeland, rockabilly queen Rosie Flores, and Zydeco stars Boozoo Chavis and the Magic Sounds.

Closing out the festival is Rock And Roll Hall Of Famer Johnny Otis, one of the earlier rhythm and blues pioneers and mentor to a bevy of protegees, including the legendary Big Mama Thornton.

He will perform as The Johnny Otis Show featuring Barbara Morrison, Jackie Payne, Heather Marie, and Gail “Little Bit” Muldrow.

Preceding Otis and friends will be Oakland’s Tower of Power, known for its powerful horn section and 1970s hits.

Other featured artists include Chicago blues queen Koko Taylor & Her Blues Machine, Rod Piazza And The Mighty Flyers, Elvin Bishop with special guest Little Smokey Smothers, and local favorite Lavay Smith And Her Red Hot Skillet Lickers.

Event producer Tom Mazzolini founded the San Francisco Blues Festival in 1973. His efforts over the years earned him the Blues Foundation’s 1998 prize for blues promoter of the year.