Before starting this lesson you should be aware about
How chords are constructed
Circle of fifths
Chord substitution is to replace a chord by another one to give a more personal flavor to a song or a chord progression. There are two types of substitutions :
Diatonic substitutions (chords that have the same tonal function)
Chromatic substitutions (Formed with chords from other keys or modes)
In this lesson I will focus on Diatonic substitutions.
Major chord substitution
Major 7 diatonic chord substitution
Dominant chord substitution
Half-diminished chord substitution
Minor 3rd substitution
Flat 5 substitution
Back cycling. (ii - V – I)
THE NEVER ENDING ii-V-ii-V…. CHORD PROGRESSION
1. Diatonic substitution
Diatonic substitution consists in replacing a chord with another chord built on the notes of a harmonized scale, provided that these chords share common tones (that they have the same function) and support the melody. This is called diatonic substitution because you are not altering any notes of the scale.
To explain this substitution, we can harmonize a diatonic scale by stacking thirds to highlight the relationship between the main chords and their different substitutions. Diatonic substitutions are generally made between chords whose roots are a diatonic third apart. These are the chords that have the most notes in common.
As you can see, the following chords have three notes in common :
The I chord share notes with the III and the VI.
The II share notes with the IV.
The IV with the VI.
The V with the VII.
The notes of the diatonic scale called scale degrees have specific names and numbers related to their function and positions to each other on the scale.
The first note ( I) is named Tonic.
Leading tone (VII).
2. Major chord substitution
In the minor / major tonal system, the most important relationship is the one that unifies the major chords (I, IV) to their relative minors. Each major chord can be substituted with the chord whose root is a minor third down. Thus giving :
The I chord (tonic) can be substituted with the VI chord (submediant), they have three notes in common : C, E and G.
The IV chord (subdominant) can be substituted with the II chord (supertonic) , they have three notes in common : F, A and C.
As it is shown in the table below, the relative minor of the I chord is Am7 (a minor third down C). The relative minor of the IV chord (Fmaj7) is Dm7.
Tonic Relative minor
In the following example the I chord (Cmaj7) is replaced by the VI chord (Am7). This substitution works well when the I chord is followed by the II chord (diatonic IIm7 or dominant II7).
Secondary relative minor
You can substitute the I and IV chords (Cmaj7 and Fmaj7) either with their relative minors (as shown above) or their secondary relative minors. To find the secondary relative minor of any major chord think up a major third. Indeed, Am7 is the secondary relative minor of Fmaj7 and Em7 is the secondary relative minor of Cmaj7.
Tonic Secondary relative minor
In jazz music, the most used substitution is the substitution of the I chord with its secondary relative minor. Here is an example of what a common I-VI-II-V sequence can become. As you can see, Cmaj7 is replaced by Em7.
3. Major 7 diatonic chord substitution
To resume, the I chord (Cmaj7) can be substituted with the VI (Am) and the III (Em7). The IV chord (Fmaj7) can be substituted with the VI or the II (Dm7).
4. Dominant chord substitution
There are two main possibilities to replace a dominant seventh chord, the V chord (G7). It can can be substituted with the VII (Bm7b5) and the II chord (Dm7).
Substitute dominant minor - II-V
The first possibility, and surely the most used in jazz music, is the substitution of the dominant chord (V) with the II chord. Example in the key C major, for G7 you can play Dm7 instead. This technique is discussed in the Joe Pass guitar style book.
The following example shows you how you can replace Dominant 7 chords from the bridge of rhythm changes. Each dominant 7th chord is replaced by the minor II chord of its related key.
Rhythm changes chord substitutions
Now let's take the first four bars of a blues progression. In bar 4, Bb7 can be replaced by a II-V sequence (Fm7 Bb7). You can also call it a II-V substitution.
5. Half-diminished chord substitution
Even if it is rarely used in jazz music, you may be interested in this following second substitution. This is the substitution of the dominant with the half diminished chord, degree VII of the major scale. Indeed, the half-diminished chord contain the 3 top notes of the V chord. Example with G7 (V) and BØ (Bm7b5). The 3 top notes of G7 are B, D and F representing the major third (3), the fifth (5) and the minor seventh (b7) of this dominant chord. The three first notes of Bm7b5 are B, D and F, respectively root (1), minor third (b3) and diminished fifth (b5). Now, try to add a ninth to the dominant seventh chord and you get the minor seventh of the half diminished chord. As you have understood, you can replace the V7 chord with the VII chord.
6. Minor 3rd substitution
A minor 3rd substitution takes either the II chord, the V chord, or both the II and V up or down a minor 3rd before resolving to I.
Suppose a II–V–I progression in G major. I substituted the II chord (Am7) up a minor 3rd to Cm7, then to D7 (the V chord), and finally to Gmaj7 (the I chord). | Am7 | D7 | Gmaj7 | -> | Cm7 | D7 | Gmaj7 | Or for the same II–V–I progression in G major, I’ve substituted F7 for D7 (the V chord), resolving to Gmaj7 (the I chord).
| Am7 | D7 | Gmaj7 | -> | Am7 | F7 | Gmaj7 |
Or I substituted the Am7 and D7 (the II & V) up a minor 3rd using Cm7 and F7, before resolving to Gmaj7 (the I chord).
| Am7 | D7 | Gmaj7 | -> | Cm7 | F7 | Gmaj7 |
This is a great way to create some different sounds for a II–V–I progression with no limits. By moving in minor 3rds, it creates more or less a diminished sound.
7. Flat 5 substitution
The flat five substitution is a chord that you can use as a substitute for any dominant chord. It applies very nicely to the 12 Bar Blues, because of the use of Dominant 7th chords.
When you play a dominant chord there will always be a chord that you can substitute for it and still have it sound good. That substitute chord is a flat 5th above the original chord. So if you are playing an E7, the substituted note would be Bb7. It is called a Flat-Five Substitute because if you are in the key of E the V note is B, and the bV is Bb hence the name Flat-Five. The Flat-Five chord substitutes so nicely because of the notes which are contained in the original chord and the Flat-Five chord. Let’s look at the notes in each chord.
If you will notice, the 3 note and the b7 note are the same notes. Remember that Ab = G♯. That is why the chords can be substituted for each other.
The reason that the notes are the same is because the interval between the 3 and the b7 is a diminished 5th. A tritone divides the root note and octave in half. In other words, It is the same distance from the root note as it is from the root note’s octave. This is why you get the same notes for both chords. Because all dominant chords (7th, 9th, or 13th) must contain the 3 and b7 notes, this substitution works every time.
Another great thing about this substitution process is that you do not have to substitute a Dominant 7th chord for a Dominant 7th chord. You can substitute any dominant chord for any other dominant chord. For example you can substitute a Bb13 for a E9 chord. On the circle of fifths, the flat 5 substitute would be the opposite chord on the circle.
8. Back cycling. (ii - V – I)
Back cycling is finding chords that will lead you to a target chord. This is very useful if a chord is played for a longer time. Suppose you have a progression :
| Cmaj7 | Cmaj7 | Fm7 |
And you want to give it some more “juice”
What you do is move to your target chord (Fm7 in this example) with other chords resolving into it. See how again the circle of fifths again can help.
To get to the Target(minor or major) chord play :
Target chord -2 & add m7 (II)
Target chord -1 & add 7 (V)
Target chord(minor or major).
So in the above example to get to the target chord Fm7, we play
| Cmaj7 | Gm7 C7 | Fm7 | To clue here is to pretend that the chord you want to back cycle to is each time seen as a I chord, this means you see it always as a “virtual ii - V – I” progression.
I read a while ago that someone was calling it a “nested ii - V – I”
The nice thing is that you can do this endless. Also the chord you use in you back cycling can be back cycled, and these again can be back cycled, etc … So the progression :
| Cmaj7 | Gm7 C7 | Fm7 |
can become :
| Am7 D7 | Gm7 C7 | Fm7 |
Because Gm7 back cycled is Am7 (II) -> D7 (V) -> Gm7 (I)
9. THE NEVER ENDING ii-V-ii-V…. CHORD PROGRESSION
In the previous lesson we talked about the II-V-I progression (Back cycling). If this concept is clear to you then this one becomes an easy one for you.
In jazz it is very popular to leave out the I and only play the II-V of the key of that chord then continue with II-V of the key of the next chord and again for the next one in order to resolve at the end to I.
Take for example a simple progression in the key of C major. 〚 : C | G7 | Dm | Am : 〛 Am ||
converting this in series of II-V progressions it becomes this. 〚 : Dm7 G7 | Am7 D7 | Em7 A7 | Bm7 E7 : 〛 A maj7 : || The A maj7 at the end is no specific substitution, I just use a maj7 because it gives a more jazzy sound than the normal Am in this case.
Example of a chord progression with several substitutions implemented :
All material has been gathered and summarized by Peter Bos