Blues is a
genre and
musical form that originated in
African-American communities in the "
Deep South" of the United States around the end of the 19th century. The genre developed from roots in traditional
African music, combined with
European American folk music. Blues incorporated
spirituals,
work songs,
field hollers,
shouts, and
chants, and rhymed simple narrative
ballads. The blues form, ubiquitous in
jazz,
rhythm and blues and
rock and roll, is characterized by the
call-and-response pattern, the
blues scale and specific
chord progressions, of which the
twelve-bar blues is the most common. The
blue notes (or "worried notes") which are often thirds or fifths which are flatter in pitch than in other music styles, are also an important part of the sound. Blues
shuffles or
walking bass reinforce the trance-like rhythm and form a repetitive effect called a
groove.