Barry Harris Harmonization

key points:

1. each 6th and diminished chord there are no repeated notes. Independent movement on all 4 voices of each chord is achieved when sequentially progressing from one to the other

2. only 2 chords in each series but can apply the 6th to maj7, 7, or min7 chords (ex: C6 applies to Cmaj7 or Fmaj9, and Am7; Cm6 applies to Am7b7 and F9)

3. ‘two’ chord approach can apply to virtually any scale: ex: C melodic minor would be Cm6 Ddim7 back and forth all way up scale with c d eb f g ab a b c as top or bottom note. Note the extra note ab is from Ddim7. Whatever scale you are using, add the extra note will comes from the IIdim7 chord.

4. function of approach tones, during single note improvisation we have the alternative to add that chromatic passing tone between any other consecutive pair of notes in the scale

5. Borrow the upper neigbor in the 8-note scale to add additional tension & resolution to each chord, ex: C6sus (f on top) to C6 (e on top), Ddim7 (g then f on top), C6 (g on top) to C6#5 (g# on top), Ddim7 (ab then a on top), C6 (a on top) to Cmaj13 (C6 with b on top), Ddim7 (b then c on top), C6 (c on top) to C69 (d on top), Ddim7 (d then e on top)

Also you can borrow from any of the other voices as well, i.e. in addition to the top voice of each chord, you can the second highest, the second lowest or the lowest as well.