Re-harmonizing Jazz Piano Songs for Guitar: The Basics
When it comes to Jazz, the practice of reharmonizing songs for any particular instrument or artistic taste is all but commonplace. Reharmonizing can give a personality to a song that would otherwise be dull, boring or too dry for a more modern audience. Despite the rule-breaking, often freeform nature of Jazz music itself, reharmonizing a Jazz piece across various instruments can involve even more creativity than simply playing one.
What exactly is re-harmonizing? It is defined as “changing or altering the harmonic structure of a specific song while maintaining the original melody”. This can be done in a myriad of ways, including the utilization of borrowed chords, modal interchange, adding or subtracting notes to certain chords, the seven Greek modes, modulation, and much more. The boundaries of your re-harmonization ability are defined by your imagination while abiding by the rules of music theory. The practice of re-harmonization can become even more exciting when applied to your guitar playing.
Take, for example, legendary Jazz pianist Bill Evans’s most renown compositions, Waltz for Debby. Waltz for Debby, a song Evans wrote for his niece Debby, begins in the common Waltz time signature of ¾ and is played in the key of F Major.
When played on the piano, this song involves complex communication between the right and left hands as well as expert facility of the keys, bouncing back and forth between the Fmaj7/A(F Major 7 with an A in the bass), Dm7, Gm7, C7, A7/G, and D7/F# chords with a descending bass line. Unless you’ve been playing the piano for many years and possess powerful knowledge of jazz voicings along with proficient left and right hand technique , you won’t be replicating this composition any time soon. As a musician with equivalent guitar-playing skill, this is where re-harmonization comes into play.
The first thing to notice when re-harmonizing a Jazz piano song for the guitar is the locality of chords and geometric similarities the fret-board shares. An entire chord progression can be played in relatively the same area on the fret-board, say, within just a couple of frets.
This is not the case with the piano primarily because of how the left and right hands work in tandem to produce harmony that stretches across a wider plain than what the guitar is capable of. When you change musical keys on the piano, the sharps and flats become relative, as well. This is not the case with the guitar which has a single, entirely transposable geometric shape.
As a result of such consistency it becomes easier to edit and alter harmonic structure on the guitar than on the piano since it may only require a single finger to make major chordal changes.
Back to Waltz for Debby, the Fmaj7/A chord that introduces the song has multiple voicings.
Personally, I prefer to play this as an open chord on the 10th fret with my index finger fretting the F note on the 3rd string, since the bass note is an A and I can simply play the A-string open while trying to replicate the treble notes that Evans plays in a higher octave. It's also a very natural hand position since my pinky can extend to fret the note C on the 13th fret on the 2nd string.
Choosing this fingering for the Fmaj7/A chord sets the rest of the chord progression up in the same neighborhood. From here, the only thing I have to do to make the change from the Fmaj7/A to the Dm7 is remove my pinky finger, fret the note D on the low 6th (E)string and pluck the Dm7 triad.
My index finger is already barring the two notes on the 10th fret from the previous chord and as a result provides a comfortable and fluent transition. From there I descend down to the Gm7, C7 and so on, dynamically playing and adjusting each chord, adding or subtracting a few notes to each chord structure and sometimes descending chromatically.
This is only a small example and basic explanation of how re-harmonization can work on the guitar and most of it is a matter of preference. The locality of the fret-board works to your advantage. Think chord dynamics, comfort, and chord relativity. The fret-board is comprised of many small towns that all carry their own advantages. It's up to you to decide which one to visit.