The Chicago blues is a form of blues music that developed in Chicago, Illinois by taking the basic acoustic guitar and harmonica-based Delta blues and adding electrically amplified guitar, amplified bass guitar, drums, piano, and sometimes saxophone, and making the harmonica louder with a microphone and an instrument amplifier. The music developed when poor Black workers did the "Great Migration" from the South into the industrial cities of the North such as Chicago in the first half of the twentieth century.
Chicago Blues has a more extended palette of notes than the standard six-note blues scale; often, notes from the major scale and dominant 9th chords are added, which gives the music a more "jazz feel" whilst still being in the confines of the blues genre. Chicago blues is also known for its heavy rolling bass.
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