Jazz guitar chord extensions are the notes above the 1, 3 and 7 of a chord, like the 9 and the 13. The simplest way in is to take shell chords on a 2-5-1 and put one extension on top: D minor 7 9, G7 13, C major 7 9. Then adjust those tensions one level at a time.
I love chords. Those 2-5s on guitar are so beautiful to me, and one of the reasons I love these colors is that they’re so lush. This lesson walks through four levels, from shell chords with a 9 or 13 on top, to the flat 13, the tritone sub, and then all of it mixed together.
What are chord extensions on jazz guitar?
Extensions are the colors that sit above the basic 7th chord: the 9, the 11 and the 13. On guitar, the easiest place to hear them is on top of a shell chord, the 1, 3 and 7.
I remember starting to play jazz. You learn these guitar shapes, you play a 7th chord and think, ah, super jazzy. Then you realize it doesn’t really cut it. It’s cool, but when you listen to the albums, they’re doing all these other things with more extensions and sounds and colors. The four levels below are how I explore that, and it’s actually really simple.
Level 1: add the 9 and the 13 to your shell chords
Take a 2-5-1 in C with shell chords and put one extension on top of each chord. Play it in a loop, really slowly.
- D minor 7 9. The shell chord with an E on top. D up to E is a 9.
- G7 13. Keep that same E on top. Literally the shell chord, with the 13 as the top note.
- C major 7 9. The shell chord with a D on top.
Why is it a 13 and not a 6? If you count from G, E is the 6th note, but with an octave displacement it’s still a 13.
Now run it through a sequence of 2-5-1s a whole step apart: D minor 7, G7, C major 7, then C minor 7, F7, B flat major 7, then B flat minor 7, E flat 7, A flat major 7, and keep going. You could keep the same shape for some of these, but there are other options, so for B flat minor 7 9 I move to the 6th string. After six keys you’re back where you started, and you can do the same thing a half step above to cover the rest.
When you play these in other keys you create a kind of kinesthetic memory, and you start knowing the sounds. I’m really memorizing the sound of the 9 to the 13. While I’m playing, I tell myself the name of each chord, and oftentimes I sing the bass. This is something a lot of piano players do. I was actually working on some 2-5s on the piano one morning and realized we need to do it as guitar players too.
Level 2: change the 13 to a flat 13
Keep the D minor 7 9, but on the G7 move the top note from E down to E flat. That’s the flat 13, and it gives the dominant chord a harsher, clashier sound on the way to C.
The flat 13 is really coming from a minor key. G7 with E flat on top hints that we’re going to C minor. We’re doing a little cheat, because we land on C major 7 instead. That’s why it’s a little clashy, but it’s really cool.
Then do both. Play the G7 13 and then the G7 flat 13 before you resolve. Now the top notes make a little line, E to E flat to D. This is the moment where these little extensions get into the music. If you just learn a 2-5, it’s not that exciting. Once you start hearing these as melodies, that’s where cool things start happening.
It’s not just like copy paste shape. We really want to understand the colors.
Rotem Sivan
Run the 13 to flat 13 idea through the same six keys. On B flat minor 7 9 to E flat 7, it’s the same move: the 13 changing to the flat 13. Knowing that it’s the 13 going to the flat 13 every time is really helpful. In the video I also play the A section of All the Things You Are, first with plain shell chords and then with these extensions, so you can hear the difference.
Level 3: add a tritone substitution
Instead of G7 13, play D flat 7 9. So the progression becomes D minor 7 9, D flat 7 9, C major 7, and you run that in the same sequence of 2-5s.
There are quite a few voicings you could use for the D flat 7 9, and I show the one I’d use in the video. D flat 7 and G7 sit a tritone apart and share the same 3rd and 7th (F and C flat, which is B), which is why one can stand in for the other. Again, these are simple devices, and it’s the same 2-5-1 with one more chord color. For more on this move, the ii-V-I guitar lesson builds up tritone subs and other substitutions level by level.
Level 4: mix the tritone sub with the 13 to flat 13
This is kind of my favorite, because we’re mixing both ideas: the 2-5 with the 9s, the tritone sub, and the 13 to flat 13. It’s not the only way, but it works, and then I run it in a sequence like the others.
I know it’s a lot of motion. Once you get the grip on one kind of color and tension and it makes sense in your ears, the fingers will follow. The only thing you need to do is play it really slowly and in time. Listen carefully and you’ll get it. It’s not a big deal.
A chord extensions practice idea for today
- Loop one 2-5-1. D minor 7 9, G7 13, C major 7 9, really slowly and in time.
- Name it and sing it. Say each chord name to yourself as you play it, and sing the bass.
- Move it. Take the same idea through C minor 7, F7, B flat major 7 and the next keys down in whole steps.
- Add the flat 13. Once the 9 and 13 feel familiar, slip the flat 13 in after the 13 and hear the little line on top.
If you want the chords underneath all this rebuilt from the ground up, Jazz Chord Essentials covers how a 7th chord is built, the four main colors (major 7, dominant 7, minor 7 and half diminished) and every inversion on the 4th, 5th and 6th string sets.
Frequently asked questions
What’s the easiest way to add extensions to jazz guitar chords?
Start with shell chords, the 1, 3 and 7, and add one note on top. On a 2-5-1 in C, that gives you D minor 7 9 with E on top, G7 13 keeping the same E, and C major 7 9 with D on top.
Is the E on G7 a 13 or a 6?
It’s a 13. On G7, the E is the 6th note counting up from G, but because it sits an octave higher, above the 7th of the chord, it’s named the 13. Same note name, with an octave displacement.
What’s the difference between a 13 and a flat 13 on a dominant chord?
On G7, the 13 is E and the flat 13 is E flat. The flat 13 comes from a minor key, so it hints at C minor. Resolving it to C major 7 is a little cheat, which makes it a bit clashy, but it sounds really cool.
What’s a tritone substitution in a 2-5-1?
You replace the V chord with the dominant a tritone away. In C, instead of G7 you play D flat 7, so the progression becomes D minor 7 9, D flat 7 9, C major 7. Both dominants share the same 3rd and 7th.
Pick one key, get the 9 to the 13 sounding clear in your ears, and the fingers will follow.
