Today, I’ll be exposing the “3-5-7-9” principle of chord substitution to you.
Although there are so many ways to approach the concept of chord substitution, the principle you’re about to learn will blow your mind.
Attention: This chord substitution principle hasn’t been taught anywhere in the world and this is because “I got it over the shower” just like my mentor and role-model, Jermaine Griggs. So, you have to take what you’re about to learn seriously because it can revolutionize your playing if well understood.
Let’s jump right into it.
The “3-5-7-9” Principle Of Chord Substitution — Explained
The concept of chord substitution is concerned with the replacement of a given chord by another chord. Although the replacement for the given chord may be related or foreign, there must be a theoretical explanation for the substitution.
Let’s get started by taking a look at the foundation of the “3-5-7-9” principle of chord substitution.
The Foundation Of The “3-5-7-9” Principle Of Chord Substitution
There are four tones in every seventh chord: the first, third, fifth, and seventh tone. In the C major seventh chord:
C is the first tone
E is the third tone
G is the fifth tone
B is the seventh tone
Each of these tones can be associated with numbers like 1, 2, 3, 4, etc. So, in the case of the C major seventh chord, C is the 1, E is the 3, G is the 5, and B is the 7.
The “3-5-7-9” principle of chord substitution is concerned with the replacement of the 1-chord with other chords that are derived from the consideration of the 1, 3, 5, and 7 as the 3, 5, 7, and 9.
“Here’s How It Works…”
The 1 in the the C major seventh chord:
…which is C:
…can be considered as the 3, (the 5, the 7, or the 9) of a major ninth chord in another key.
“Here Are The Possibilities…”
The 1 in the C major seventh chord (which is C):
…can be substituted with another major ninth chord where C is the 3, the 5, the 9, or the 7.The 3 in the C major seventh chord (which is E):
…can also be substituted with another major ninth chord where E is the 3, the 5, the 9, or the 7.The 5 in the C major seventh chord (which is G):
…can also be substituted with another major ninth chord where G is the 3, the 5, the 9, or the 7.The 7 in the C major seventh chord (which is B):
…can also be substituted with another major ninth chord where B is the 3, the 5, the 9, or the 7.
Let’s go ahead and explore these possibilities for the 1 (which is C):
“The Consideration Of The 1 As The 3…”
The 1 (which is C):
…can be considered as the 3.
So, in what key is C the 3? The answer is the key of Ab major:
So, the Ab major ninth chord:
…is the substitute for the 1-chord in the key of C major:
…and this is because we’re considering the “1 as 3”.
The Ab major ninth chord:
…is a chromatic chord in the key of C major:
…and has only C and G:
…in common between Ab and C.
Therefore, we’ll have to rearrange the notes of the Ab major ninth chord in such a way that either C or G is the highest-sounding note. This gives us these two voicings of the Ab major ninth chord:
Voicing #1:
Voicing #2:
Following the same guideline, other substitutes can be derived.
“The Consideration Of The 1 As The 5…”
The 1 (which is C):
…can also be considered as the 5.
It is only in the key of F major (and minor):
…that C is the 5.
So, the F major ninth chord:
…is the substitute for the 1-chord in the key of C major:
…and this is because we’re considering the 1 (which is C) as 5 (in the key of F major [hence the F major ninth chord]).
“The Consideration Of The 1 As The 7…”
The 1 (which is C):
…can also be considered as the 7.
It is only in the key of Db major:
…that C is the 7.
So, the Db major ninth chord:
…is the substitute for the 1-chord in the key of C major:
…and this is because we’re considering the 1 (which is C) as 7 (in the key of Db major [hence the Db major ninth chord]).
“The Consideration Of The 1 As The 9…”
The 1 (which is C):
…can also be considered as the 9.
It is only in the key of Bb major (and minor):
…that C is the 9.
So, the Bb major ninth chord:
…is the substitute for the 1-chord in the key of C major:
…and this is because we’re considering the 1 (which is C) as 9 (in the key of Bb major [hence the Bb major ninth chord]).
“In A Nutshell…”
The consideration of the “1 as the 3”, “as the 5”, “as the 9”, and “as the 7” gave us four substitutes for the 1-chord in the key of C major:
“The 1 as 3”:
“The 1 as 5”:
“The 1 as 7”:
“The 1 as 9”:
Every other tone of the 1-chord (the 3, 5, and 7) can also be subjected to the “3-5-7-9” principle of chord substitution.
