Updated: Aug 5, 2021
Believe it or not, when I started playing the saxophone towards the end of primary school, I was predominantly a Classical saxophonist - a very rare breed indeed. If someone pinched my beloved Ferling Etudes and put a Jazz chord chart in front of me, I would be toast.
For many Classical players, the call for an "improvised solo" will strike fear into their hearts, and it's not difficult to understand why. When we hear Jazz musicians talk about the nitty-gritty of improvisation and harmony, it can often sound like another language, even to a seasoned musician; "mixolydian scale" this, "tritone substitution" that - it all becomes hyper-technical and extremely off-putting very quickly.
If you're studying A-Level Music and feeling like you're hitting your head against a brick wall when your exasperated teacher explains for the thousandth time what the 'Rhythm Changes' are, you've come to the right place - I'll walk you through the very basics of Jazz harmony and get you swinging in no time!
If you're not familiar with Jazz harmony, the chord chart below below is likely to mean very little to you (asides from the roots spelling C-A-D-G...):
One of the most common questions I get asked when I run a Jazz workshop is "what do all those chords mean?"
The simple answer is to tell them straight up what notes each chord is comprised of and be done with it, but this seldom answers their question. With the progression above, the first chord is C-E-G-B, the second is A-C#-E-G-Bb, the third is D-F-A-C and the final chord is G-B-D-F. If you're a newbie to Jazz, that's probably offered you next to no insight as to what's really going on here.
Let's start with some roman numerals. If we let our first chord be I, using the C major scale as our reference (with C being I, D being II, E being III etc.), then our overall progression is I-VI-ii-V. Take note of how the third chord is in lower case, we'll get back to that later. This structure is a classic jazz progression, and you'll probably spot hundreds of progressions which briefly follow this form in many Jazz standards.
"Okay Oscar, but I'm still confused: what makes this progression so special?"
Excellent question. You're probably familiar with the perfect cadence in Classical harmony (V-I), this simple progression is extremely common in all types of music and acts as a 'music full-stop', so to speak - that V-I movement is very satisfying to our ears. It's exactly the same in Jazz, but these V-Is are spruced-up by fancy chord extensions - think of it as Classical harmony after an espresso.
Take a look at the progression above. Notice how A-D is a V-I (in the key of D), D-G is a V-I (in the key of G) and then imagine this sequence looping, G-C would also be a V-I (in, you guessed it, the key of C).
"I've got it Oscar! So Jazz harmony is all about V-Is with fancy extensions. Lesson over?"
Not so fast - let's join the dots. We understand that this progression uses V-I movement to create a satisfying bass line, but now we're going to look at the most common Jazz cadence of all: the ii-V-I. Remember I said take a note of how that third chord was in lower case? In a standard ii-V-I, the first chord is always minor (hence the lower case roman numerals) - often adding what we call the 'dominant seventh' on top. So in the key of C, our chord ii would be D minor 7 (D-F-A-C). Next, we have our dominant chord, V. This is a major chord with the dominant seventh on top, so in the key of C, chord V would be G dominant 7 (G-B-D-F).
"Hang on, hang on. Oscar you lost me at dominant seventh - what is this?"
Good shout! When we talk about extensions in Jazz, we talk in terms of the root note of our chord. So in our example of of G dominant 7, the dominant seventh is the 'flat seventh' - so in the G major scale, note 7 is normally F# - we want to flatten this so now it's just F. Let's do the same in C. Note 7 is normally B, but we want the dominant 7 - so that would be Bb. This would make C dominant 7 C-E-G-Bb. Ready to go on?
Our final chord is our major 'home' chord, I. In the key of C, this is just C major! To spice things up, we often add what is known as the 'major seventh' on top. This is just the 'normal' seventh of the major scale on top. So in C this would B, making our C major 7 chord C-E-G-B. And that's our Jazz ii-V-I!
To wrap-up, our ii-V-I cadence in Jazz is often extended, so it will feature minor 7 (chord ii), dominant 7 (chord V) and major 7 chords (chord I). I've summarised our chord types below alongise their 'short hand' notation:
Chord ii - Minor 7 (ex. Am7) - a minor triad with the 'b7' added
Chord V - Dominant 7 (ex. D7) - a major triad with the 'b7' added
Chord I - Major 7 (ex. Gmaj7 - sometimes we use a little triangle to represent the 'maj') - a major triad with the 'major 7' added
Don't be disheartened if this is still confusing! Jazz harmony is difficult and it's very unlikely that just one read of this guide will transform you into the next John Coltrane or Dexter Gordon! Take your time to understand the ii-V-I, try writing the ii-V-I cadences in the keys of G, D, F and Bb - then add in the extensions we discussed and work out what notes are in each chord!
Case Study: Rhythm Changes
You're likely to have heard Jazz musicians talking about 'Rhythm Changes' - what on earth is this all about?
First things first, 'changes' refers to the chord progression of a given piece of jazz music. I've attached the 'changes' to one of my favourite Jazz standards, 'It Could Happen To You'. So Rhythm Changes is the name given to the chord progression of George Gershwin's 'I've Got Rhythym'. This tune has been immensely popular with Jazz musicians and composers and countless tunes have been written using the chord progression of 'I've Got Rhythm' - some famous examples include 'Oleo' (Sonny Rollins), 'Moose the Mooche' (Charlie Parker) and 'The Eternal Triangle' (Sonny Stitt).
"Right I get it Oscar, they're cool and that - but what are they?!"
In the chord below, is what is a fairly standard Rhythm Changes - bear in mind that Jazz musicians love to re-harmonise tunes so don't expect every Rhythm Changes to look exactly like this!
Some structural notes before we dig into the harmony. 'I've Got Rhythm' uses what we call a 32-bar AABA form, we hear the 'A' section twice before moving onto the 'bridge' (B) before going back to the A section, with each section being typically 8 bars long. Understanding this structure is crucial to analysing many Jazz standards and when we're discussing these changes.
"Enough waffle already, can we crack on with some serious analysis Oscar?"
We most certainly can! We'll only look at the A-section for now. Looking at the first two bars, do you recognise this progression? Hopefully, you'll remember that this is our I-VI-ii-V we talked about earlier, notice how the ii-V in bar 2 uses a minor 7 chord on ii and dominant 7 chord on V - very idiomatic. You might be wondering why in bar 3 the first chord is Em7, and not Cmaj7. This is crucial, not all dominant 7 chords resolve down a fifth (ie. V-I). Bar 3 is a perfect example of chord substitution taking place, instead of going back to Cmaj7 (which would sound perfectly fine), we move to Em7.
"Wait what?! Why on Earth would anyone do that?"
Take a look at bar 3 closely, what does this structure look like? By swapping Cmaj7 for Em7, we create a iim7-V7 cadence in the key of D leading into the next bar. Great! Then in bar 4, we have another iim7-V7 in the key of C - this chain of ii-Vs is very common in jazz standards and helps make the progression far more exciting.
The next 4 bars are a little more complex, but this is the hardest part of this tune's harmony so stay with me! The technique between bar 4 and bar 5 is very common in many standards and we essentially see a dominant chord in bar 4 (G7) resolve to the minor 7 chord built on the same root (Gm7).
"Eh? First we're swapping V-Is with ii-V-Is, now we're letting chords resolve wherever they like?"
Sit tight. Let's imagine in bar 5, we had a chord of C7 instead as shown in line A above. This would sound pretty sweet as in bar 4 we'll get a V-I with G7-C7 and in bar 6 we have F7 - this could mean we've got some more V-I movement going on with C7-F7. But remember that in Jazz, ii-V-I cadences are more idiomatic than just plain V-Is. So, we change our V-I cadence between bars 5 and 6 into a ii-V-I cadence by adding in Gm7 as in line B of the picture above - instant Jazz!
Between bars 6-7, things are a little trickier still. I'll leave you with this to think about in terms of analysing why Bb7 resolving to Em7 makes sense. One common jazz harmonisation technique is called 'tritone substitution' which can be very briefly explained as the dominant 7 chord resolving down one semi-tone: for example F7-Emaj7. It creates some delicious tension and keeps the listener (and the soloist) on their toes! Thinking about what we said earlier about wanting to turn simple V-I cadences into ii-V-Is, why have we ended up with Bb7-Em7-A7-Dm7 between bars 6 and 7? I'll let you ponder on that...
"I think I need to give my brain a rest Oscar..."
Phew! Now I appreciate that was a lot of Jazz theory in a very short amount of time! This guide has given you an outline into what ii-V-Is are, what chord types go with which part of a ii-V-I and how chord substitution works in the context of the Rhythm Changes - that is plenty for anyone to go away and chew on!
Still itching for more to do? Here are some ideas for consolidating what we've learnt today:
Write out the iim7- V7-Imaj7 cadences in all 12 keys, then adding what notes are in each chord
See if you can spot all the ii-V-Is in a Jazz standard - 'There Will Never Be Another You' is a great place to start!
Have a look at a 12-bar blues, can you turn any of the V-I cadences into ii-V-I cadences? What about the VI-I cadences (HINT: check out the 'backdoor progression')?
We've discussed major Jazz harmony, but what about minor Jazz cadences? Listen to 'Softly As In A Morning Sunrise' - what is different about the changes in the 1st four bars? How do the chord types differ in a minor ii-V-I?
Blog Post Crafted by Oscar
Oscar studies Philosophy, Politics and Economics (PPE) at the University of Warwick.
When he's not studying or tutoring GCSE Maths and Science, Oscar plays saxophone and co-ordinates the Small Band division of the University of Warwick Big Band.