The idea of chord substitution is central to modern jazz improvisation, and there are many different approaches to this subject, by many different musicians. Especially well-known is the work of the American saxophonist Jerry Bergonzi. This project is my own approach, where I describe the substitution shape and demonstrate techniques for the conceptualisation of the substitution "on the hoof". I'm currently working on expanding this much further, and will give many more examples, but as yet I haven't made much of an effort to make this user-friendly. As it stands, you'll need more than a passing familiarity with jazz theory for this to work for you in any practical way, but I think it can be helpful if you are looking for a way to expand your improvising over familiar chord sequences.

I am always happy to hear from people who have suggestions. Send me a mail.

When playing a line over a chord sequence it is possible to employ three- or four-note arpeggios which belong to the same harmonic area as the original chord, instead of always thinking in terms of scales and modes. This is a way to introduce controlled dissonance or even bitonality to a solo, while never playing completely outside the function of the harmony.

These secondary figures are often derived as extensions of the original chord. It is important to remember that these new labels on the harmonic event are not themselves harmonic events in the conventional sense, and it is therefore meaningless to treat them as such. They are simply pools of notes which can be arpeggiated in various ways to maintain a distance from the underlying chord sequence. They can also be used as chord substitutions by a guitarist or pianist where the bass follows the original changes.

In the first table I give diatonic substitutions, taken from various degrees of the original chords without altering the basic tonality. Since the fourth of the major chord at I is so unstable, it is assumed that it is preferable to use a lydian mode as default.

This second table deals with the altered progression, where the V chord has a strong b9:

In the third table are possible substitions for a minor II-V-I, where the I chord is melodic minor.

Certain of these strings are easier to conceptualise than others, and some are so at odds with the harmony that functionality is almost completely lost. To make this information of practical use it is important to choose which ones work best, and also to mix substitutions from different degrees when reharmonising a II-V. Especially effective are those which share a virtual bass note, or those which appear to move in parallel - in other words, those which have a kind of integrity.

Here is a list of some of those I feel work best for the major II-V-I ( a combination of the possibilities from the first two tables). These are grouped according the to the harmonic starting-point at II, and for the most part arranged thereafter as chromatically as possible.

Let us look at a practical application of these ideas. Taking the beginning of “Giant Steps”, which contains three major key centres, I outline the five alternate harmonic schemes.

Am currently transferring this work to HTML. More to come.