27/06/2026
Reharmonization: Chord Substitution
If reharmonization is like painting a car, then chord substitution is like choosing a different shade of the same color—going from blue to indigo, or rose to pink. Chord substitution involves replacing a chord with another that has similar harmonic function. It allows you to change the sound of a tune while still retaining much of its original color.
In order to use chord substitution as a reharmonization technique, you must understand the division of the seven diatonic chords into three groups or families. Each of these chord families has a function. A chord’s function is its tendency to move or remain stable within a musical phrase. Let’s use the key of C as an example.
Tonic Family Analysis Symbol: (T)
The tonic family of chords has a resting function. Chords in this group tend to sound stable. They have little sense of forward motion and are almost always found at the phrase endings of popular and standard tunes. Diatonic chords built on the first, third, and sixth degrees of a scale are the members of this group.
Tonic chords share several common tones. The chords are considered restful because they do not contain the fourth degree of the scale, which is F in the key of C. The fourth degree of any major scale is known as a tendency tone—it tends to lead to the third degree of the scale when played over IMaj7.
Subdominant Family Analysis Symbol: (SD)
Chords in the subdominant family have a moderate tendency to move ahead within the musical phrase. All chords in this family contain the restless fourth degree of the scale. Chords built on the second and fourth scale degrees make up this group. The V7sus4 is also included in this family, because it contains the fourth scale degree instead of the third. (Using a suspended fourth instead of a third eliminates the tritone that gives a dominant family chord its characteristic sound. The tritone function is described below.)
Dominant Family Analysis Symbol: (D)
Chords in the dominant family sound unresolved and have a strong tendency toward resolution. They are said to have a “moving” function. Dominant chords almost always precede phrase endings in popular and standard tunes.
