We all know George Shearing’s chords on piano, but what this really means on guitar, as some confusion still exists with block chords; let’s have a look.
The following provisional reflexions have emerged on what it should means.
1. usually 4 notes–if not possible, go for 3 notes, eliminating the bottom voice;
2. all voices are played in rhythmic unison;
3. top and bottom voices the same notes, either an octave apart (2nd and 5th strings) or two octaves apart (1st and 6th strings);
4. the two inner voices are associated chord guide tones (3rd and 7th of respective chord), optimally played on 3rd and 4th strings;
5. guide tones form following double stop intervallic shapes: (a) M7, m7 are P5 or P4; (b) 7, m6, and diminished chords are always tritones; (c) P4 double stop shape is better amenable to barring and frees up other fingers; (d) P4 double stop shape is 7 to 3; P5 double stop is 3 to 7.
Piano generally deals with 5 notes (4 w/ a doubling) which allows for a greater mix of function and color, but it’s not very playable on guitar with standard techniques.
We are left with 4 note chords (3 w/ a doubling)
So the tendency is to go for the color when possible. 3rd or 7th or neither, opens up many more possibilities.
But at a certain point it stops sounding like George Shearing. Just to say, Red Garland was another pianist who made excellent use of octave encased chords.