Guide tones are simply the third and seventh notes of a chord (sometimes the third and sixth if the chord is a simple triad or sixth chord). Guide-tone voicings have long been popular with jazz musicians, including guitarists Grant Green, Jim Hall, and pianist Red Garland. Thelonious Monk often used guide tone voicings to inform and accompany his improvised solo piano excursions. Bebop guitar phenom Tal Farlow even used guide tones as a basis for his blazing solo lines.
For purposes of clarification and identification, we’re going to call chords with the root on the sixth string (E) root 6 chords, and chords with the root on the fifth string (A) root 5 chords. Example 1 illustrates root 5 and root 6 voicings for guide-tone Cmaj7 and Cm7 chords. Notice how the guide tones invert from one string to the other, depending on which string has the root—for example, a root 5 voicing places the third of the chord on the D string and the seventh on the G string, whereas a root 6 voicing is exactly the opposite. The beautiful thing is that all of these voicings are movable and transposable! Therefore, it’s important to get acquainted with each of the different shapes in Examples 2a and 2b.