Do you find yourself listening to a jazz tune where the piano player or guitarist plays a chord that stands out but somehow still seems to work? In jazz, it’s common for chordal players to substitute certain chords for different chords.
When this happens, it’s called a chord substitution. Chord substitutions are sometimes written into compositions by composers, and, other times, they are the deliberate choice of the chordal player or an improviser who is implying a chord substitution by their note choices.
Whether or not you are a chordal player, you still need to understand chord substitutions because they are a fundamental part of the jazz language.
A jazz tune’s lead sheet or “Real Book” chord progression is just a starting point or suggestion. The freedom to substitute chord changes and create different kinds of harmonic movement is one of the great allures of playing jazz music.
In this post, we will answer the question, “What is a chord substitution?” and go over 5 essential chord substitutions you need to know when learning jazz.
This post is a great starting point to learn how chord substitutions work in music theory. However, if you want a deeper dive into what makes a chord substitution work, check out the Learn Jazz Standards Inner Circle.
You’ll get access to many courses taught by professional jazz musicians, including music theory lessons on what makes a chord substitution work and how to use them when comping or improvising.
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Table of Contents
What is a Chord Substitution?
A chord substitution is a musical technique where a composer or chordal player chooses to use a different chord instead of the original chord. Chord substitutions work because they often have the same (or nearly the same) harmonic function as the original chord, share the same common tones, or produce smooth voice leading that resolves the progression.
The substituted chord often provides new and creative harmonic interest while maintaining the original chord progression’s overall structure and direction.
This technique is widely used in many music genres, including jazz, classical, and popular music, to add variety and complexity to the harmony.
Here are five types of chord substitutions often found built into compositions or otherwise implied by jazz players:
- Diatonic Substitution: This chord substitution occurs when a chord is replaced by another chord from the same key. For example, in the key of C major, you might replace a C major chord (or the tonic chord) with an A minor chord because both chords share the same notes (C and E). When improvising, using diatonic substitutions to inform your lines adds chord extensions to your soloing. If the chord on the lead sheet is Cmaj7, but you outline an A minor chord substitution, you are implying a C6 chord.
- Tritone Substitution: This is a common chord substitution technique in jazz. The tritone substitution, or “tritone sub,” is when a dominant seventh chord is replaced by another dominant seventh chord, a tritone (three whole steps) away. More information on these is down below.
- Secondary Dominant: Also known as a borrowed dominant, a secondary dominant substitution happens when a chord is replaced by a dominant 7th chord, a perfect fifth below or a perfect fourth above a target chord.
- For example, in a I-vi-ii-V chord progression in C major (Cmaj7-Am7-Dm7-G7), we can replace the I, the vi, and the ii chords with their secondary dominant substitutions.
- The I chord, or Cmaj7, can be substituted with E7 (III7), the V7 of the vi chord.
- The vi chord, or A minor, can be substituted with A7 (VI7), the V7 of the ii chord.
- The ii chord, or D minor, can be substituted with D7 (II7), which is the V7 of the I chord.
- The new chord progression is III7-VI7-II7-V7 or E7-A7-D7-G7. You might recognize these changes as the bridge to Rhythm Changes, which uses a III7-VI7-II7-V7 chord progression in Bb or D7-G7-C7-F7.
- For example, in a I-vi-ii-V chord progression in C major (Cmaj7-Am7-Dm7-G7), we can replace the I, the vi, and the ii chords with their secondary dominant substitutions.
- Modal Interchange: With this chord substitution, a player will choose chords from the parallel minor or other modes. For example, in C major, you might use the Bb Major chord, which is borrowed from the parallel minor of C major or (C minor). In C minor, a Bb chord is the bVII7.In jazz, this is often called a bVII7 chord substitution and is often a substitute chord for the V7 chord. You can find examples of the bVII7 chord in jazz standards like Cherokee or Stella by Starlight.
- Relative Minor/Major Substitution: The relative minor key shares the same key signature and, therefore, the same chords with major keys. So, in a progression, a major chord can be replaced with its relative minor or vice versa.For example, in C major, you could replace the tonic chord, or C major, with A minor, the tonic chord the relative minor key.
The Importance of Learning Jazz Chord Progressions Before Practicing Chord Substitutions
It’s important for musicians studying jazz to know some of the common jazz chord progressions that you will encounter in jazz standards. By learning the most common progressions, which often include chord substitutions written into the harmony, you’ll have a serious leg up on learning jazz songs and getting your jazz improvisation together.
Check out this crash course on how chord progressions are built for more information.
So, we’ve introduced 5 different types of chord substitutions, but let’s look at a few examples of chord substitutions in greater detail. Jazz musicians often employ The following chord substitutions when improvising or comping on changes.
5 Jazz Chord Substitutions You Need to Know
1. iii Replaces the I
You will often see the iii chords replacing the I chord in jazz. For example, in the key of C, a Cmaj7 is replaced by an Emin7.
The common chord progression you will see this happen in is the I-vi-ii-V. This would be Cmaj7-Amin7-Dmin7-G7. But when the iii replaces the I, it becomes Emin7-Amin7-Dmin7-G7.
It’s important to note that in this example, the vi chord has been made into a dominant 7th chord (VI). Remember, replacing a chord with a secondary dominant chord is common in jazz! You always want to think of the target chord and determine what the V7 of the target chord would be. In this case, the target chord is Dm, so the V7 of Dm is A7.
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2. #i Diminished Replaces the VI
If you turn the VI chord into a dominant chord rather than its diatonically correct minor 7 form, you open up additional substitution possibilities. One of these is replacing VI with a diminished 7th chord.
Check out this blog post on how to substitute a dominant chord to learn more.
Here’s the context:
I-VI-ii-V, which in the key of C is Cmaj7-A7-Dmin7-G7. When we a #i diminished for the VI it becomes Cmaj7-C#dim7-Dmin7 G7.
Think of it this way: a dominant 7 can be an altered dominant (b9,#9, b13, #11). If we were to make the VI chord into a dominant7(b9) chord, it would share all of the important notes except the bass note of the chord with the C#dim7.
3. Tritone Substitution
We’ve written much on tritone substitutions and won’t get too deep in this lesson. Let’s instead focus on the most typical example.
First off, for those who are new to this concept, what is tritone substitution?
A tritone substitution occurs whenever a chord is substituted or replaced by another chord with a root a tritone interval away. Example: G7 is replaced by Db7.
One of the most common tritone subs is the Tritone Sub of V.
The V7 in a ii-V-I chord progression can be substituted with the bII7 chord because these two chords share the same guide tones.
For example, in a II-V-I progression in the major key of C (Dm7-G7-Cmaj7), the G7 could be replaced with a Db7. This works because the guide tones of a G7 chord, B (the 3rd) and F (the 7th), are enharmonically equivalent to the guide tones of a Db7 chord, Cb (the 7th) and F (the 3rd).
Therefore, despite a different root note, the harmonic function of the two chords remains the same.
4. I-IV-iii-VI Turnaround to a ii-V-I
You may have noticed that it’s possible to substitute entire chord progressions. When improvisers and chordal players do this, it’s often called a turnaround. There are many creative ways to play a turnaround.
Technically, a turnaround brings you back to the I chord, no matter how you get there.
Our first example above, the iii-VI-ii-V, is a turnaround heading back to the I chord. A I-VI-ii-V is a turnaround because it cycles back to the I chord.
But there are other ways to get there.
One that you will see come up repeatedly is throwing in the IV chord to cycle back to the I.
5. Chromatic ii-V’s
This is a very common substitution/add-on, so pay attention. Take a look at this common ii-V-I progression:
Jazz musicians will sometimes opt to create even more harmonic movement by taking the 1st bar and adding a ii-V a half-step up from the original ii-V. They will then push over the original ii chord into the second bar, giving each chord two beats each.
Thelonious Monk’s “Round Midnight” and Benny Golson’s “Along Came Betty” have chromatic ii-Vs built into their standard chord progressions.
Now there are even more changes to improvise over and connect to each other. Pretty cool, right?
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