Everybody wants to play “outside” the chord changes. They think there is something mysterious about getting outside the changes. In my experience, the phenomenal players that I’ve studied with along with the legendary players I’ve learned from on recordings, approach playing outside the harmony much in the same way they approach playing inside the harmony: they play over specific chords.
Playing other chords instead of the original chords is often called superimposition. Superimposing these substitutions on-top of the original set of chord changes allows you to keep a logical structure to your lines, while escaping the typical path.
An easy entry point to utilizing these substitutions is over ii Vs. It’s quite simple. Instead of playing the ii V in the original changes, you’ll instead play a ii V from a different key. The important thing to remember is: you still have to resolve the ii V to the original key and you have to engage your ear to make it sound right. Theoretical concepts can give you ideas of what to play, but then you must use your ear to tailor the concept for that particular situation.
Where these substitutions come from
The 3 substitutions presented in this article occur time and time again in the standard jazz repertoire; they are devices that composers have used for centuries to add tension directly before a resolution point (V7 to I).
The first substitution is simply what jazz educators call the “backdoor ii V” (iv- bVII7 I ). And you can find it in many tunes.
The second sub is a common V7 substitute, the bVI of the dominant, so over D7 it would be Bb7. This is also very common to see in tunes.
The third sub is simply a tritone sub, which again is very common.
The point is, these substitutions are not used solely in improvisation and they’re not some hip modern device; they were used to reharmonize the original pre-jazz changes of tunes to create the versions of tunes that jazz musicians have been playing for years. They are essentially ...