blues

Blues is a music genre and musical form that originated among African Americans in the Deep South of the United States around the 1860s. Blues has incorporated spirituals, work songs, field hollers, shouts, chants, and rhymed simple narrative ballads from the African-American culture. The blues form is ubiquitous in jazz, rhythm and blues, and rock and roll, and 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. Blue notes (or "worried notes"), usually thirds, fifths or sevenths flattened in pitch, are also an essential part of the sound. Blues shuffles or walking bass reinforce the trance-like rhythm and form a repetitive effect known as the groove.

Blues music is characterized by its lyrics, bass lines, and instrumentation. Early traditional blues verses consisted of a single line repeated four times. It was only in the first decades of the 20th century that the most common current structure became standard: the AAB pattern, consisting of a line sung over the four first bars, its repetition over the next four, and then a longer concluding line over the last bars. Early blues frequently took the form of a loose narrative, often relating the racial segregation, discrimination, and other challenges experienced by African Americans. By this time, the blues has coalesced into an important aspect of African American culture, expressing the hardships and culture of black communities. These narratives often detailed the specific harsh realities of the Deep South, including the difficulties of sharecropping and the economic devastation caused by the boll weevil.