These maps read like chord diagrams
where the fingerboard is seen as if you were watching another
guitarist. Here instead of fingerings or pitches, we see
intervals related to their root. The example above
is a basic open position D chord where the fret on the far right
would represent the notes on the open 4th & 5th strings.
The diagram below has thirteen frets, showing an entire octave
on each string.
|Here we are using " E " as our root note.
Starting with the open 6th string, ( top-right) we can see
all the roots ( every E ), and all the fifths ( every B
), up to the 12th fret on the first string (bottom-left). A
feature of the guitar is that while all the other strings are tuned
a fouth apart, the interval between strings 2 & 3 is a major third.
Here we see how that alters the symmetric geometry of the fingerboard.
|This is the same diagram, but now showing the major third.
Here the three members of the E major triad are shown in every location.
In the resulting patterns we find familiar chord shapes. These
are framed in red and show us the three inversions of one major chord
on the top four strings (see Tertian Harmony). Fingerboard harmony is
based around these few simple shapes. Joe Pass coined the acronym
" C A G E D ".
Look for the bass note for all five shapes. "G & A"
share the same triad on strings 2 to 4, but they approach it from different
positions. The "C & D" shapes share the same upper
triad on strings 1 to 3.