alteration of any single tone by a half-step produces four different dominant
7th chords.
When the same chord shapes unfold
horizontally in one key, they automatically create four inversions on the selected
string group as shown in Fig. 2.
Last month, we looked at how the
augmented triad shapes change quality
when moved vertically across the fretboard. A similar pattern appears with the
diminished form. In Fig. 3, we see how
a Gdim7 shape moves to D9 and then to
G7
5 when shifted vertically. Once again,
as with the augmented procedures, these
particular fingerings indicate the vertical
analysis of three automatic voicings.
Raising one of the chord tones by a
half-step alters the initial diminished
form by producing a minor 7
5 form.
This is illustrated in Fig. 4.
To completely understand the nature
of these forms and how they relate to the
fretboard, it is essential that you transfer
these concepts to other string groups.
In upcoming lessons, the harmonic
forms we’ve covered so far will not only
continue to expand, but they’ll also
serve as the architectural groundwork
for melodic linear studies. In the coming
months, we’ll discover how to apply these
linear studies both vertically and horizontally across the fretboard.
Ah-ha!
Minor 7
5 Chord. The basic formula for these chords is 1–
3–
5–
7.
Another way to think of them is as
a standard minor 7th chord with a
lowered fifth. Many times you see
minor 7
5 chords functioning as a ii
chord in a minor ii–V–i progression.
Tunes such as “Stella by Starlight,
“Round Midnight,” and “Gloria’s
Step” all use minor 7
5 chords in
both diatonic and parallel functions.
Another name used for these chords
is half-diminished, a term that’s used
when the chord is functioning diatonically as the vii in a major key.
This description distinguishes the
chord from its diminished 7th sibling
(which has a 1–
3–
5–
7 formula).
—Jason Shadrick
The chord shapes shown in Fig. 3 can be a little tricky to play. In the above photos, you can see
how each one lines up on the fretboard. By moving each shape directly across the fretboard
you can move from Gdim7 to D9 and finally to G7%
5. If you are feeling adventurous, explore
the different types of chords you get by moving the G7%
5 shape horizontally up the fretboard.
Remember, you don’t always need the root!—Jason Shadrick
Fig. 3
Vertical Positions
Gº7
D9
G7b5
2413
2413
2413
Fig. 4
Diminished Parental Form
Gº7
2413
B¨‹7b5
E‹7b5
G‹7b5
D¨‹7b5
3412
2413
1211
