Blues

Blues music, usually called the blues, has its origins among the freed black African slaves who worked on the cotton fields of northwest Mississippi following the American Civil War. Blues music has always been a hallmark of African American culture in the United States. It was influential in the United States Civil Rights Movement and has influenced the development of most forms of popular music, including rock and roll, jazz, hip-hop, rap, and country music. Once hailed for being a foundation of modern music, traditional blues has declined somewhat in the last few decades, largely due to the evolution of more modern blues-based forms, such as rhythm and blues, later R'n'B. The blues, like other forms of music, has also been a casualty of fashion, as other forms of music (rock and roll, rock, pop, country) came to the fore at various times.

Other older music forms such as classical and jazz benefit from being taught at schools; this adds to their longevity. The very freedom and informality that gave the blues its unique form has probably aided in its decline.

Origins

African Americans were the originators of blues music via the African field songs that they sung together as they worked. Blues music was influenced in its inception by field hollers and rythmic dances called 'jump ups', which evolved into a system of music with a singer who would engage in call and response with his/her guitar. He would sing a line, and the guitar would answer. Gospel and Scots-Irish ballads also influenced the emerging art form as did what was known as traditional music, prevalent especially in Irish American immigrant communities where the focus on the old homeland was strong, with instruments such as the bódhran, accordion, tin whistle and banjo shaping the development of country music throughout the United States. This folksy music, designed to lift the spirit of those in oppressed environments, would likely have resonated with African American slaves more than the formal European Classical style of music prevalent amongst the cultured elite at the time, which only house servants would have had access to.

From this came the music that discomfited many white Americans, who termed it the 'Devil's music', as it influenced movement of the body in ways unknown to traditional European-based forms of music. Field hollering later evolved with fusions of traditional Irish folk and the quickly developing American country music into what we now know as the blues.

12-bar blues

Much of modern music is built around 12-bar blues, which plays the root, fourth and fifth chords of the song's particular key. There are any number of variations, but three of the most popular are shown below. Straight 12-bar blues, in the key of G, would have this pattern of chords which would be repeated throughout the song. The pattern is suited to eight-note bass walks whenever one chord is played for two bars:

Straight 12-bar blues pattern:

| G | G | G | G |

| C | C | G | G |

| D | C | G | D |

Instead of staying on the root chord (G) for so many bars, blues song often use the "quick turn-around" variation, which jumps to the fourth chord (C) on the second bar and right back to the root on the third bar of music.

"Quick turn-around" 12-bar blues pattern:

| G | C | G | G |

| C | C | G | G |

| D | C | G | D |

By ending on the firth chord (D), this pattern leaves a sense of "tension" at the end of pattern. This tension can be relieved by ending on the root chord, like this.

12-bar blues resolving on the root:

| G | C | G | G |

| C | C | G | G |

| D | D | C | G |