Jazz Theory

Chords Construction – Part 3

This page deals exclusively with common chords equivalents. Jazz theory becomes really easy once you understand that certain chords are “interchangeable”… sometimes they contain exactly the same notes and sometimes they contain another chord’s extensions.

If you don’t read music (“notes” on the staff) and if you’ve never encountered any music theory in the past, this is a good place to start. Go slow, read on and don’t be afraid to ask questions!

In the course of this jazz theory article series about chord construction, you’ll find music theory info about triads and sevenths chords, how to add extensions, chord equivalents, diatonic chords and finally a neat theoretical process to understand what extensions are “allowed” on jazz chords.

My goal here is to have you realize that you already know thousands of chords. (that is, if you already play a little bit) Why? Well, since any single chord can be put to use in many different contexts, it’s not a matter of learning more chords… it’s only a matter of finding more USES to the ones you already know! (-:

Jump to a page:

Chord Construction 1: Triads and Sevenths
Chord Construction 2: Adding Extensions
Chord Construction 3: Equivalents [You’re Here]
Chord Construction 4: Chords from three scales

Addendum: The “Chord Extensions Finder” Technique



  • You should know…
    You should know about building triads, basic seventh chords and *the idea* behind extensions. If not, please read the previous installments of this article series.
  • Extensions: In jazz theory we generally label the tones 9, 11 and 13 as extensions. Alterations (b9, #9, #11, b13, etc.) are also very common, especially on dominant chords.
  • Important: Most recorded jazz from the past 50 years employs chords harmonized to the 9ths (minimum) … The basic 7th chords are the foundation in jazz theory, but in real life when jazz musicians play they always use extensions. Learning jazz chords like this (at least to this extent: 1-3-5-7-9) has become crucial.


What Are Chord Equivalents

In a few words, chord equivalents are chords that can easily be interchanged, either in your mind, on the instrument or litteraly on the sheet music. Chord equivalents may not have the same “harmonic function”, but they may allow you to have some sorts of “jazz theory shortcuts” in order to find more uses for a single chord.

Not sure? Okay, here’s an example: You know Em7 chord, right? What if I told you that from now on, you may play Em7 on your instrument whenever you see a Cmaj7 on sheet music? Does it make sense? NO! Hold the presses!!! Because Em7 and Cmaj7 are completely separate entities in jazz theory…

… but if we took a closer look, we would notice that the notes in Em7 are E-G-B-D. Okay. Are those notes “acceptable” to be played over some kind of C major chord?

Notes in Em7: 

  • E – (it’s the third of C). Check
  • G – (it’s the fifth of C). Check
  • B – (it’s the seventh of C). Check!
  • (So, those are the tones 3, 5 and 7 of C major 7th.)

And what about that “D” note? It’s simply the 9th of C. So by playing an Em7 when you see a Cmaj7 on sheet music, you are simply playing “on extensions” of Cmaj7 (in fact the notes 3-5-7-9) resulting in a Cmaj9 sound. Welcome to jazz theory!

Clearer now? Good! (-:


So, on this page we will be looking at two different types of equivalencies for jazz chords: there’s when two different chord symbols imply the exact same notes and there’s when the equivalent is in fact “playing on extensions” of our original chord. (The Cmaj9=Em7 example above is of the latter type).

Since I cannot walk you through the same process (as above) for each and every of the chord equivalents, I insist…

You MUST investigate these on your own. You have to understand what notes are added, left out, on what extensions is the equivalent putting the emphasis, etc.

We don’t have enough space here to go into every details (and into every key!) so I’ll simply provide you with a list of common equivalents found in the “real world” jazz theory. Once you get familiar with a handfull of those “tricks” of interchange below, you’ll find more and more use for the chords you already know. That’s my goal, once again, to have you realize that you know LOTS of chords already… you just have to find more uses for your same old stuff. (-:

IMPORTANT: Don’t generalize too much! If you’re playing the above example of Em7 when it’s in fact C major 7, it may sound bad IF you don’t respect the registers. Always watch out for the low notes. If you play the guitar’s lowest string (E) against a “straight Cmaj7”, it will clash! Use common sense, listen for that kind of “bad stuff” and let your ear be the final judge.


Equivalents: Same Exact Notes

The very important “maj6 to min7” and “min6 to min7(b5)” are
C6 = Am7
Cm6 = Am7(b5)

The symmetrical diminished 7th chords are
B diminished 7th = Ddim7 = Fdim7 = Ab (or G#) dim7

Symmetrical augmented triads…
C aug = E aug = G# augmented

Yup. That’s all there is to know. Once you get this in your ears and finger plus find out about passing diminished chords (see the Barry Harris Harmonic Method), you’ll find this extremely valuable…

A very powerful trick after you nail the “maj6 to min7” relationship, common passing chords and inversions is… adding extensions to the above! Great potential there.


Equivalents: Playing on Extensions

It’s highly recommend that you work each equivalence out for yourself. Explore, see how it works. There’s tremendous potential for creativity there!

B dim 7 = G7(b9)
Bm7(b5) = G9
Bbmaj7 = Gm9
Dm7 = G9(sus4)


Fun with triads (in general):

Eb/C = Cm7
D/C = Cmaj7(#11) (lydian)
G/C = Cmaj9
Em/C = Cmaj7

Note: you can take any seventh chord and see its 3-5-7 degrees as a triad. Same goes with further extensions : 7-9-11 or 9-11-13 can constitute triads. They’re called upper structure triads. Explore!


More fun with triads (dominant chords only):

Simply a G7sus4 sound with a ninth.

Gives a G7sus4(b9 b13) sound.

Is a G7(b9 b5) sound.

Really cool sound.

Same as above.

Lydian dominant sound. It’s G13(#11).


What’s Next?

In part 4 of this jazz theory article series, we’ll land our two feet right on the earth and talk about diatonic chords: the harmony that is already present within a scale in it natural state. We’ll use our usual suspects: the major, harmonic minor and melodic minor scales.


Jump to a page:

Chord Construction 1: Triads and Sevenths
Chord Construction 2: Adding Extensions
Chord Construction 3: Equivalents [You’re Here]
Chord Construction 4: Chords from three scales

Addendum: The “Chord Extensions Finder” Technique

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