The Birth of Bebop Jazz

Bebop jazz is a musical style for virtuoso musicians. This style of jazz produced four changes: it required a greater understanding of jazz theory; complex instrumental melodies were introduced; complicated chords and rhythms were added to the rhythm section; and a cult of serious musicians evolved. The improvisational style shifted from adorning an original melody to organizing new patterns of quick, active, melodic lines. The musical pattern often ended abruptly with two notes, suggesting the word "be-bop". Musicians developed relationships between distended chords and esoteric scales. These notes are called melodic extensions and were added to chords by pianists to add harmonic color.

The birth of bebop jazz in the 1940's is considered the beginning of modern jazz. This style grew out of the small swing groups, but placed a much higher emphasis on technique and on complex harmonies, rather than on singable melodies. Alto saxophonist Charlie "Bird" Parker was the father of this movement, and trumpet player Dizzy Gillespie ("Diz") was his primary cohort. His quintet and other small group recordings that featured Dizzie and Bird formed the foundation of bebop and most modern jazz.

Much use was made of blues and popular songs of the day, including songs by George Gershwin and Cole Porter. The original compositions began to diverge from popular music for the first time. It was not intended to be dance music. The compositions usually featured fast tempos and difficult eighth note runs. Many of the standards are based on the chord progressions of other popular songs, such as "I Got Rhythm", "Cherokee", or "How High The Moon". The improvisations were based on scales implied by those chords, and the scales used included alterations such as the flatted fifth.

The development of this form of jazz led to new approaches to accompanying as well as soloing. Drummers began to rely less on the bass drum and more on the ride cymbal and hi-hat. Bass players became responsible for keeping the pulse by playing almost exclusively a walking bass line consisting mostly of quarter notes while outlining the chord progression. Pianists were able to use a lighter touch, and in particular their left hands were no longer forced to define the beat or to play roots of chords. In addition, the modern standard form became universal. Performers would play the melody to a piece (the head), often in unison, then take turns playing solos based on the chord progression of the piece, and finally play the head again. The technique of trading fours, in which soloists exchange four bar phrases with each other or with the drummer, also became common. The standard quartet and quintet formats (piano, bass, drums; saxophone and/or trumpet) have changed very little since the 1940's.

Notables include saxophonists Sonny Stitt and Lucky Thompson, trumpeters Fats Navarro, Kenny Dorham, and Miles Davis, pianists Bud Powell, Duke Jordan, Al Haig, and Thelonious Monk, vibraphonist Milt Jackson, bassists Oscar Pettiford, Tommy Potter, and Charles Mingus, and drummers Max Roach, Kenny Clarke, and Roy Haynes.