Originally this allowed time for the singer to make up the last line. Some notes used in blues music may be flattened by a semitone. These are normally the third, fifth or seventh notes of the scale.

Guitar legend T-Bone Walker, top, pioneered the jump blues style of the 1940s, and BB King, above, headed the blues revival in the 1960s Chattanooga-born Bessie Smith, nicknamed the Empress of the ...