Despite the stylistic changes that occurred as New Orleans and Hot Jazz developed into Swing, early jazz demonstrates an underlying unity of approach to the melodic interpretation of harmony, and one which continued within Boogie Woogie, R&B, Rock ‘n Roll, Skiffle and Country music, even if modern jazz took a different route.
Chords underly the structures of tunes and improvisations in early jazz and swing. Most of the chord types found in jazz of the 1920s and 30s may be derived from a standard 7-note scale. For example, using only the notes of C Major, we can produce the following chords.
Note the similarity between Major 6 and Minor 7 chords: e.g. F6 is an inversion of Dm7.
Let’s carry on building the common chords found in early jazz and swing, while still limiting ourselves to notes of the C Major scale, for now.
Note the similarity in content of these five chord types.
Now we need to leave the confines of a standard 7-note scale in order to create four more chord types found in early jazz. In some contexts, these derive from the minor mode and the influence of the Blues: i.e. think of D# as Eb in the key of C Minor.
Note the similarity of content in each pair of chords above. Also note the construction of the Bo7 chord, which shares its content with diminished 7s built on D, F and Ab. Similarly, G+ shares its content with two other augmented chords, B+ and D#+, for reasons that should be obvious. If not, then I recommend you brush up on your basic music theory.
These extracts are taken from the author’s free iBook: Early Jazz Theory, David Burnand, 2013. https://itun.es/gb/3ECVN.l
In a later blog, I explore the typical ways that these common chords are elaborated in early jazz improvisation.