This second chord progression (in Figure 9-6) is based on the relative minor
of the first one (in Figure 9-5): The key of E minor is the relative minor of G
major. You could think of this minor version as a substitution— a chord used
instead of the one you would normally use — for the more obvious major
version.It is important to realize that there are many other possible ways that you
could harmonize a simple melody. Our melody could be harmonized into
other keys. It could even exist outside of a diatonic framework. The second
melody here (in Figure 9-6) defines the key signature by presenting some defi-
nition harmonically. It only takes two notes sounding together to imply a har-
monic framework in which a particular melody exists.Many substitutions for chords are implied by melodies and harmonies. A large
portion of what jazz is all about is being aware of these substitutions and
incorporating them — and the scales attached to them —improvisationally.
But before we start playing around with substitutions, it’s a good idea to tune
into the more usual, mainstream harmonies available.Harmonizing Using the Circle of Fifths ........................................................
Take another look at the Circle of Fifths (Figure 9-7). We have talked about the
fact that as you go clockwise around the Circle, you move through the key
signatures by the interval of a perfect fifth. But did you notice that going
counterclockwise moves you in perfect fourths?So what? Well, consider that if you start on any slice of the Circle of Fifths pie,
the fifth of the selected key is on its right, and the fourth of the selected key
is on the left. For example, select G. The next one clockwise is D, and counter-
clockwise is C. D is the fifth tone (dominant) of the G major scale, and C is the
fourth tone (subdominant) in the key of G. The fourth and the fifth are the
most important tones in a scale, next to the tonic, and there they are huddled
snugly against the chosen key. The IV chord and the V chord are the most
important chords after the I chord.A musical composition, as we have said many times, is like a good story; it
has a beginning, a middle, and an end. In music, we use the terms statement,
development, departure, and resolution(or recapitulation).96 Part III: Harmony and Structure