When looking to compile a collection of pitches for musical improvisation, the music of bebop jazz era lends itself to a particular type of rhythmic feel and flow. Most of this music is composed in a 4/4 shuffle feel that is complemented by flowing eighth note patterns. A 4/4 measure can contain a maximum of 8 eighth notes, so an 8 pitch scale would be the optimal tool for musical improvisation in this musical style.
The bebop scale is an eight pitch scale composed by introducing one addition chromatic pitch to a modal scale. There are four types of bebop scales based on the four most common jazz seventh chords. The four most common jazz seventh chords are the four chord qualities found in the diatonic seventh chords of the major and minor keys. They are the major 7th, minor 7th, dominant 7th and the half diminished 7th chords. This is demonstrated below by the included graphics that display the major and minor diatonic seventh chords.