Guitar player here. I have been learning about chord extensions and how they can be used to color to a basic progression or when playing a solo. However as I was doing research on this it seems that a common way to think of them is not as an extension of a chord but rather two chords being played simultaneously. For example a Dm over a G would make a G9.

This seems like a potentially powerful concept that makes it possible to reuse triads and tetrads in a solo band or improvisation situation. For example over a G7 you could play an Am arpeggio rather than thinking about a G13. However I find this quite daunting as the sheer number of possibilities across all keys is a little overwhelming.

Is this an effective way to think of and practice working with chord extensions? Or are there down sides to this? Should I focus on practicing extended arpeggios or understanding which triads and tetrads extend a particular chord?

5 Answers 5


Not sure how Am over G7 gives G13. And this is maybe the stumbling block. Yes, some triads do fit with others to produce extensions. But what's wrong with just using the originals and adding extensions?

A lot of chords are made by the 'stack of thirds' as in G7 - G B D F. Add an A, and we have G9. Add C and it's G11, an E and it's G13 (generally sounds better without the 11). So it's neither complete stacked thirds nor two chords piggy-backed.

To me, it makes more sense to actually know what constitutes a chord, and work from there. The amount of extra information to know (and learn!) is perhaps slightly less than knowing what other chord is needed to produce an extension to the existing chord.

Then there's changes: ♭5, ♯5, ♭9, ♯9, as common examples. It's going to be better, surely, to think in terms of 'what note gets sharpened?' rather than 'what's the new chord I need to find the notes of before I play an extension?'.

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    @NenadK - both John and I point out (individually) that G13 is better without the 11 (C). Personally, with me it often gets played without the 9 as well. That's another problem - extensions do not need every note to be played as well - playing an 11 doesn't have to have 5,7 and 9 all in there. So the idea of two piggy-backed chords falls down at that point too.
    – Tim
    Jun 25, 2020 at 7:57
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    @NenadK I’d just like to add that the reason the 11 is not a good addition to a 7th chord is the minor 9th interval between the 3rd and the 11th creates a very strong dissonance that doesn’t resolve well. However making it a 7sus4 by replacing the 3rd with the 4th is a good option and 9 and 13 work great on 7sus4 chords. Jun 25, 2020 at 9:09
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    @JohnBelzaguy - I always think of 11 chords as 7ths and 4ths. After all, 7+4=11...
    – Tim
    Jun 25, 2020 at 9:16
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    To me in practice, G11 = F6/G, and it's used like a Gsus4. The third is not played. If you play the theoretical third, it sounds wrong for the song and basically ruins the harmony. Similarly, in a 13 chord the 11 is left out, because the meaning is never to be a sus chord, its role is to be a dominant seventh - with a major third and a seventh, but with extra flavor. Leaving out the 9th makes the difference in taste between 9 and 13 clearer. The systematic theoretical definitions for 11 and 13 chords just aren't very good chords in practice, and the de-facto definitions are different. Jun 25, 2020 at 9:54
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    G7 = (1, 3, 5, b7) and its relative ii is (9, 11, 13) and this is the definition of a 13th chord. We don't normally play the 11 but it's in the definition.
    – user50691
    Jun 25, 2020 at 17:13

Because of the way upper extensions are added to chords there is usually a way to touch on the basic chord plus the extensions within one scale. When you’re talking about more advanced soloing concepts the modes of the ascending melodic minor scale can be very useful in this regard. A few examples are for dominant chords that are 9, #11, 13, a melodic minor scale built on the 5th gives you R 9 3 #11 5 13 b7. A melodic minor scale built on the m2 is great for altered chords and gives you R b9 #9 3 b5 b6 b7. There are several other of these modes that are useful for other types of chords.

Triads that incorporate upper extensions can definitely be used for color and melodic material. My preference is for major triads in general, for example: a triad built on the 2nd for a 7#11 chord (say D over a C7#11) or a triad built on the m6 for a 7alt chord (say Ab over a C7alt). Your choice of Am over a G13 is not ideal however because it contains the P4. An A major triad with the #11 would be better. Like you said the number of triads contained in any upper extension chord can be daunting, say a G13#11 contains G, Bo, Dm, F+, A, C#o and Em so it’s better to narrow it down quite a bit if you want to incorporate them.

Bottom line, soloing is a very personal thing so educate yourself on different approaches and concepts but decide for yourself what the best way is to conceptualize them.


Is this an effective way to think of and practice working with chord extensions?

If you are able to see chords as combinations of other chords, it can help you play just the right notes that make the difference and add the right taste. The 9 chord being a combination of major + minor triads is a common example - if the rest of the band is playing a plain C major, you can make it a C9 by playing a G minor or Gm6. And if you know that Gm6 is equivalent to Em7-5 (just with a different bass note), you have lots of options all over the fretboard for building the C9 chord. Actually, Gm6/C has all the same notes as C9.

"Where's the nearest full C9?"

What fingerings do we have for a full C9 chord? This is probably the most commonly used one:

C9 fingering 1

Or if you want something different, you might put together something like this:

C9 fingering 2

I don't particularly like the sound of that option. But anyway, to sum it up, all two of your options are here:

Full C9 chord options

If those are the only ways you know for handling a C9, you may feel a bit uncomfortable and restricted. There must be a better way, this can't be how guitarists have to do it?!

Well OK there's this third alternative fingering I just discovered, but haven't used: Full C9 third alternative

"Where are the nearest components of a C9?"

It's almost never necessary to play all of the theoretical notes of a chord. If you just want to add the juicy notes of a C9 in a solo, or play C9 flavor with fewer notes, and if the bass is already done somehow, for example if there's a bass instrument, or if you just played it a second ago and it's still echoing in the harmonic context, why not dissect the chord and play a Gm, Gm6 or Em7-5 instead. Now we have many more options all over the fretboard. All sorts of different ways to do a C9. (there are probably errors and omissions in the animation, but you get the idea)

C9 non-full chord options

Try strumming or arpeggiating one of these Gm6 or Em7-5 chords: guitar chords to play over C to make a C9

If those shapes don't look familiar, here are the corresponding plain G minor chords: G minor chords

Learn the generic pattern, not all cases separately

However I find this quite daunting as the sheer number of possibilities across all keys is a little overwhelming.

Here's where your problem might be. First of all, you don't learn all combinations in all keys separately as hundreds of special cases. You learn the generic pattern relative to the chord's root and relative to the tonic. To make a 9 chord, you play a minor triad or a minor sixth rooted a fourth below or a fifth above the original chord's root. From C you go --> Gm6. From A you go --> Em6. The trick is to keep track of the important strategic locations. Where is the tonic note? Where's the relative major/minor's tonic note? Where are the third and seventh of the currently playing chord? Everything that happens, is relative to these strategic locations. You learn the generic pattern, not each and every possible instance and variation of it.

Here is one generic pattern for seeing the minor triad over something with the root note on the low E string. Notice that it doesn't say which frets these are. The pattern is the same all over.

9 pattern

You learn the tricks one at a time

And secondly, you don't try to learn them all in one step. You eat the elephant one little piece at a time. Slowly. First you learn and practice the generic pattern for one chord trick, in one familiar song, in one familiar key. Just ONE. And when you get that one small step done, you are happy, because you achieved something. Then you take another small step, but only after you've taken the first step. Do not watch Youtube videos, they just distract your focus away from taking small steps. I don't personally know any great jazz players, but I'm sure they all learned everything they know one step at a time.

Some other chord substitution tricks where you can superimpose different chords relative to a chord's root note to make a larger chord:

  • A C maj9 chord can be seen as a G major chord over a C major chord, or as G6/C or Em7/C. If the bass player is playing a C, just find any G major or G6 or Em7 chord anywhere on the fretboard, to add the money notes.
  • An 11 chord is a major or major six chord rooted a whole-step below the root (i.e. on the seventh). To do C11 you play Bb or Bb6 over a C bass note. This is used like a Csus4 or C7sus4 chord. (Actually you can even do Bbmaj7/C for the same thing, even though there's an A note in there.)
  • On a dominant seventh chord, play a dim or dim7 chord rooted on the dominant seventh chord's third or its seventh, or one half-step above its root (which have the same notes). Practice this in songs where there's a dominant seventh chord doing a V - I motion. (which should be nearly every song ever written)
  • On a dominant seventh chord, prepare the listener for the strong dominant by first making it an 11 chord, then a 9, and then the dim7 trick explained above
  • On a dominant seventh chord, play major triads from the half-whole diminished scale of the dominant's root. For example on a written C7 and bass note C, arpeggiate A major, F# major, Eb major triads. (if you add together the notes of those triads and the bass note C, you get the C half-whole diminished scale)

By the way, this chord-combination thing can be used for thinking about modes as well. For example in "regular" A minor you have A minor and D minor chords, but in A Dorian you have A minor and D major. In regular C major you have C major and D minor, but in C Lydian you have C major and D major.

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    Not wishing to be confrontational, but how does knowing a chord is a combination of a couple of chords, compared with knowing the make-up of the named chord help any more? Then you have two separate facts to remember, whereas knowing the make-up of a somewhat complex chord is more homogenous.
    – Tim
    Jun 25, 2020 at 16:14
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    @Tim If I think "where's the nearest full C9", I can't come up with enough alternatives from which I could select a few notes to use. But if I transform the question to "where's the nearest Gm or Gm6 or Em7-5", it's a lot easier, because those simpler chords are much more easily within reach. Actually I combine closely related chords to "equivalence groups" for this exact reason. Maybe some fretboard virtuosos can see all the notes of wide chords all over the fretboard, but I find myself searching for these helper patterns. I added two pictures, is it more understandable now? Jun 25, 2020 at 19:57
  • Great explanation. How do you get your head around target notes? In your first example if the band as a whole is playing a C9 and you are playing the Gm how do you keep it straight that the 3 of the Gm is really the 7 of the C and it's the 3 & 7 of the full extended chord you should be targeting?
    – NenadK
    Jun 26, 2020 at 3:08
  • @NenadK I'm not sure I understand what you're asking. Whichever note you want to emphasize is your target note. If you want to emphasize the 3 and 7, then have them as your target notes. Or do you mean, how to remember which of the strings has which note of the Gm? That's what you have to know about each chord pattern - which of the "dots" is which note of the chord. I have it in my mind already as a starting point - when I search for the nearest Gm, I look for the most easily reachable G or Bb and use the appropriate inversion based on that location. Or is that what you mean? Jun 26, 2020 at 10:54
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    @NenadK What you target is entirely your artistic choice. You can't target the 7 of Gm, because it doesn't have a 7. The 7th of C9 is the 3rd of Gm, and you should have that relationship clearly in your mind, because it's the note that makes the C9 a dominant-seventh type chord. In improvisation and soloing it should be you driving the chords instead of the chords driving you. You're responsible of knowing where you're placing the harmonically important notes at all times. Do you want to make it a C9? If you want to make it, say Cmaj9, where do you place your notes to do that? Jun 26, 2020 at 16:10

What you are talking about is sometime referred to as Poly-chord theory (at least that's what my guitar teacher called it in the 80s).

A simple example is any major triad and the minor triad played on its 3rd, these create a Maj 7. Consequently X maj and the minor on its 3rd are chord substitutions for each other. If you are interested is a very dense guide to poly chords, extensions, etc, pick up Ted Greene's book Chord Chemistry. There isn't mush missing in there.

As for being "daunting", I am not sure how key signature has anything to do with complexity. Most of these relations are "relative" to the tonic of the chord. Don't think of G7 and Amin think I7 and ii, now the I can be anything. Once you get the extensions and substitutions memorized in a relative sense you should be able to grab them on the fly anywhere.

They way we build up chords and their extensions is from the major scale but taking every other note, or stacking 3rds. Rewrite the Major scale as,

1, 3, 5, 7, 9, 11, 13

And there you have it. A common device is to meld triads whose roots are separated by a 3rd. Like (1, 3, 5) + (3, 5, 7) = Maj 7th. Another very common one is (5, 7, 9) + (7, 9, 11) = Dom 7th played on the V of the key (where it belongs). This gives rise to the familiar "Leading tone cadence". The authentic cadence is V --> I, most of us probably play V7 --> I as a default but in terms of poly chords you can think of the leading tone resolution as representing the V7 --> I sound. The only real avoid note is the 4th, but then again we do occasionally like the sound of an 11th chords. So, in theory, you can add pretty much any two chords together and create something "harmonious".

Take for example (1, 3, 5) + (5, 7, 9) = Maj 9 a perfectly nice chord. Just a Major 7th with a 9th on top. Sounds beautiful and there are no awkward intervals. This means you can harmonize the I with the V and people don't normally go there. However add the 7th to the V chord are get (1, 3, 5) + (5, 7, 9, 11) = Maj 11. This is not out right illegal but the 11th (aka the 4th) is an avoid note as it really wants to become the 3. As part of the chord movement V7 --> I, inserting this in between wouds create a suspended resolution. Dwelling on the 11 would probably start to get awkward. As another cautionary tale consider using the V triad as an extension to the I in the Blues. Here we usually (but not always) play dom 7 chords on the I, IV, and V. The V triad contains the Maj 7 of the I chord. This would definitely conflict with the I7 but could be made to work, for example as part of the Be Bop scale. In dealing with dom 7 chords a minor or diminished triad on the 3rd is a better choice.

Again, I cannot stress enough that there are not that many options and you don't need to consider them in every key. You want to learn them in a relative sense and just move the group to different positions on the neck. As far as practicing I'd say anywhere you invest your time will produce dividends. Pick one and work for a while. In my opinion, and this is where I spend most of my time, it helps to completely rewrite the changes to common tunes using substitutions that are based on extensions, i.e. poly-chords. This way you immediately go there. Using relative 3rd, relative minor, secondary dominant, or tri-tone, the idea is to develop in your hand as well as your mind the fact that for any chord X all these other options are "attached".


Yes, 'playing the extensions' is a perfectly valid technique. But, in practice, it might not result in anything much different to playing 'the scale of the chord', unless you make a conscious effort to treat the base chord as 'avoid notes'.

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