The Complete Idiot''s Guide to Music Theory

Substitution
Example (for the G7 chord)
Major chord a second below
Diminished chord a third below

---

Chapter 16:
Chord Substitutions and Turnarounds
209
Substitution
Example (for the G7 chord)
Diminished chord a third above
Minor 7 chord a fourth below—
over the same root
The more interesting substitutions here are the first one and the last one. The
first substitution replaces the V7 chord with a IV chord; the use of the sub-
dominant (IV) chord results in a softer lead back to the I chord. The last 
substitution uses an altered chord, so that you’re leading back to tonic with a
iim7/V—what I like to call a “Carole King chord.” (That’s because Ms. King
uses this type of harmonic structure a lot in her songwriting.) So if you’re in the
key of C, instead of ending a phrase with a G or G7 chord, you end with a
Dm7/G instead. It’s a very pleasing sound.
Functional Substitutions
Here’s something else to keep in mind. Within the harmonic context of a com-
position, different chords serve different functions. The three basic harmonic
functions are those of the tonic, subdominant, and dominant—typically served
by the I, IV, and V chords, respectively. But other chords in the scale can serve
these same functions, even if not as strongly as the I, IV, and V.
For example, the subdominant function can be served by either the ii, IV, or vi
chords. The dominant function can be served by either the V or vii° chords.
And the tonic function can be served by either the I, iii, or vi chords. All these
functions are shown in the following table:
Chord Function
Chords
Tonic
I, iii, vi
Subdominant
ii, IV, vi
Dominant
V, vii°
When you have a chord serving a specific function in a composition, you can
replace it with another chord of the same type. So if you have a IV chord, serv-
ing a subdominant function, you can substitute any of the other subdominant-
functioning chords—the ii or the vi. Along the same lines, if you have a ii
chord, you can replace it with either the IV or the vi.
The same thing goes with the other functions. If you have a V chord, serving a
dominant function, you can replace it with a vii° chord—or vice versa. And a I
chord, serving a tonic function, can be replaced by either a iii or a vi chord—
and also vice versa. It’s actually a fairly easy way to make some simple chord
substitutions.
Just in case you think you
found a mistake in the pre-
ceding table, the vi chord
can serve both the tonic
and subdominant func-
tions. It’s a very versatile
chord!
Note

---