▪ The 12 notes of the chromatic scale encapsulate the entire musical world of true Jazz. Barry Harris analyzed everything within these limits (i.e. no ♭13 chords, etc.). As with other forms of art, constraints allow deep understanding and creativity.
▪ The major scale and the dominant scale are the two fundamental scales of true Jazz. Other types of scales (e.g. pentatonic, blues scale, etc) are used, but they should be interpreted in relation to a major scale or dominant scale context. (Note: A minor scale is a major scale in disguise. Details in the next chapters).
▪ Jazz tunes generally have a scale outline that moves between a V (= notes and chords on a dominant scale, which starts on the 5th scale degree of a given I) going back to that given I (= notes and chords on a major scale, which is the tonal center). The V provides the tension, and the I is release (V is away, I is home). Tunes tend to move to additional tonal centers, but typically resolve back to the original tonal center.
▪ The circle of 4ths and 5ths: A perfect 4th is ascending (I to V), and a perfect 5th is descending (V to I). Therefore I, IV = V, I.
▪ Most Great American Songbook tunes follow an AABA form (typically 32 bars). The first two A sections are the core of the tune with slight variation. The B is the bridge, where the tune departs into a different melodic path. The final A is for resolution.
▪ The 2 whole-tone scales are a fundamental structure in the true Jazz tradition. They split the chromatic scale into two equal parts of 6 (and as we will see in the next chapter, they also “give birth” to the 3 fully diminished 7th chords, which are central to the Barry Harris method). The whole-tone scales should be analysed in a dominant scale context.
▪ All chords are intervals on major or dominant scales (except fully diminished 7th chords and ♯5 or ♭5 chords — which by this definition aren’t actual chords).
▪ Major 7th chords are on notes 1,3,5,7 of a major scale. Major 6th chords are on notes 1,3,5,6 of a major scale, minor 7th chords are an inversion of a major 6th, dominant chords are on notes 1,3,5,7 of dominant scale.
▪ A fully diminished 7th chord consists of 4 notes, each separated by a minor 3rd interval (3 semitones). For example, a C diminished 7th chord: C, E♭, G♭, A. Due to the chord’s symmetrical structure, there are only three unique diminished 7th chords: C° (C, E♭, G♭, A), C♯° (C♯, E, G, B♭), D° (D, F, A♭, B).
▪ Therefore, when playing chords, make use of their entire scale, for depth.
▪ Notes and chords are always context dependent. They can mean different things in different harmonic contexts and they belong to one tonal center at any given moment. To understand their harmonic function, identify the scale they are on, where they came from, and where they are going next.