Jazz is a music genre that originated from African American communities of New Orleans in the United States during the late 19th and early 20th centuries. It emerged in the form of independent traditional and popular musical styles, all linked by the common bonds of African American and European American musical parentage with a performance orientation. Although the foundation of jazz is deeply rooted within the black experience of the United States, different cultures have contributed their own experience and styles to the art form as well. Intellectuals around the world have hailed jazz as "one of America's original art forms". Although jazz is considered highly difficult to define, at least in part because it contains so many varied subgenres, improvisation is consistently regarded as being one of its key elements. The centrality of improvisation in jazz is attributed to influential earlier forms of music: the early blues, a form of folk music which arose in part from the work songs and field hollers of the African-American slaves on plantations.
Blues is a genre and musical form originated by African Americans in the Deep South of the United States around the end of the 19th century. The genre developed from roots in African-American work songs and European-American folk music. Blues incorporated spirituals, work songs, field hollers, shouts, 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. Blue notes (or "worried notes"), usually thirds or fifths 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.
