The Diamond is a tool. The Diamond is a language. The Diamond is a method to tonally organize chromatic playing and a way to chromatically enhance tonal playing. The Diamond is a way to understand deep relationships of motion and rest, consonance and dissonance, yin and yang in music. The Diamond is something always around us as improvisers – you most likely use parts of the concept every time you play a blues or rhythm changes or standards. If you believe in it and work on it, The Diamond is a way for you to raise your harmonic and melodic playing to a higher and perhaps more daring level.
The basis for The Diamond is the inter-relationship between four (hence the diamond shape) dominant chords built from a diminished 7th arpeggio. (ex. C, Eb, Gb, A). Each one is connected to the other through common tones and other intervallic relationships. They can be used as chord substitutions (the most usual being the tri-tone substitution, frequently used in the bebop harmonic vocabulary), for playing either melodic lines or chords. Most commonly, the diamond concept is effective in dealing with 7th chords or moments of dissonance and motion in a song. The Diamond can also influence minor chords, as a part of a ii-V progression. However, it is not as effective on the tonic or at points of rest (either major or minor).
Ultimately The Diamond is a variation on the journey before the arrival. If two travelers go from Boston to New York, one by plane, the other by bike, each has a unique journey that affects their perception of the destination, although they arrive at the exact same place. The same thing can happen when, instead of following the expected path of a ii-V-I in a standard (ex. G-7, C7 Fmaj7), you play different arpeggios (C7, A7, F#7 to Fmaj) in the same span of bars over those chords, the journey is vastly changed and therefore the arrival/resolution (Fmaj7) will have a different perspective (sound) although the destination is the same (F major scale on the I chord).
In many ways, The Diamond is an old concept. In the early 20th century, Bela Bartok created his own tonal system (itself a variation of the circle of 5ths), which served as a way to compose more chromatic and dissonant pieces while still adhering to the basic principles of tonality (rest versus motion). This was in stark contrast to some of his contemporaries (second Vienna school, Schoenberg, etc.) who expanded their use of dissonance by eschewing tonality altogether (atonality, 12 tone systems). The Axis system, as Bartok called it, is essentially the three diamonds (one starting on C, Db, and D). These acted as tonal center guides for several of his famous works, most notably Music for Strings, Percussion and Celesta. I highly suggest you read Bela Bartok, An Analysis of his Music by Erno Lendvai for more details about Bartok’s usage of his Axis system. In Igor Stravnisky’s work there is also a plethora of Diamond-like harmonic areas. From both his earlier works, like The Rite of Spring and Petrushka to some of his later work, Symphony in C or Symphony in Three Movements, Stravinsky stacks chords upon chords through the orchestra. Often those poly-chords are utilizing a minor third or tri-tone relationship (like the ‘Petrushka chord’, a C major triad on top of a Gb triad). It is not just classical music that has elements of The Diamond; jazz is also rife with its basic components. The afore mentioned tri-tone substitution (what Bartok calls a pole / counterpole relationship), common in bebop solos and chord substitutions, especially on the bridge of rhythm changes and the use of the flat 7 7th are basically part of The Diamond concept. Songs like Killer Joe that move from the flat 7 7th (Ab7 to Bb7 in this case) to the root are essentially using a substitution for the V7 chord that is a minor third away, hence a part of the Diamond (F7 to Ab7 a minor third, both resolve to Bb). Stella by Starlight, Isotope and find more) are other examples of jazz repertoire that use a bit of the diamond in their chord progressions.
I started organizing The Diamond concept in the late 1990s while I was in graduate school. At the time, I was listening deeply to Eric Dolphy and doing some transcribing and playing along with his albums. I noticed certain trends in his improvisational approach. First, he played mostly in tonal contexts although his solos sounded anything but. However, he still managed to resolve at the right moments. Secondly, it became clear that he was not just noodling around with the chromatic scale. I also noticed he used the tri-tone substitution liberally and also used the flat 7 7th. In addition, he tended to use the Lydian flat 7 scale, often a tri-tone away from the V chord he was on (basically it is the ‘altered scale’). These elements, the minor third tonal relationships, the use of the Lydian flat 7 to organize chromaticism, and harmonic substitutions allowing me to comp or solo in a bi-tonal or poly-tonal environment inspired me to organize what eventually became The Diamond. Parts of The Diamond concept have been out there in music and specifically in jazz for decades, but not until now have all the elements and ingredients been synthesized and expanded upon in one central system. Now musicians can approach modern improvising with a complete system that has flexibility to apply to any tonal or non-tonal setting.
I am honored to share The Diamond concept with you as something to add to your ever-expanding jazz and improvisation vocabulary. – Eric Hofbauer