ii-V-I CHORD PROGRESSION EXPLAINED… Once & For All
90% of jazz is built around circle of fifth chord progressions – by this I mean chord progressions that resolve down a 5th each time. For example Dm7 – G7 – C maj 7 – F7 is a circle of fifth chord progression because each chord moves down a 5th.
It’s possible for a circle of fifths to last as long as 7 or 8 chords, passing conveniently through all 7 chords from the major or minor scale (whichever the music is in). However, most of the time jazz only stays in one key long enough for 3 or 4 chords to be played. As a result you’ll encounter a fragment of a circle of fifths in one key, then another fragment in another key, and another key, and so on. Each fragment will normally play the final few chords of a complete circle of fifths – since that’s where the final resolution happens. And this is where the ‘ii – V – I’ comes from:
ii – V – I is the characteristic chord progression of jazz, and refers to the final 3 chords in a circle of fifths. So if you count backwards from the final ‘I chord’ (which a circle of fifths ends on), the 2nd to last chord will be the V chord (a 5th above the root), and the chord before that will be the ii chord (a 5th above the 5th). So ‘ii – V – I’ refers to the final 3 chords of a complete circle of fifths.
And if you ever hear the phrase ‘vi – ii – V – I’ (‘6 – 2 – 5 – 1) – well that just refers to the final 4 chords of a circle of fifths (because the vi chord is another 5th above the ii chord).
In addition, pretty much every chord in jazz is played as a 7th chord (at the very least) – so ‘ii – V – I’ really means ‘ii7 – V7 – I7’. It’s a given that each chord will have a 7th added on top, but for convenience we just say ‘2 – 5 – 1’.
2 TYPES OF ii – V – I
It’s important to understand that there are 2 types of ii – V – I – one that occurs in the major scale and a different one that occurs in the minor scale.
So if the music’s in C major scale, you’ll create your ii – V – I from the chords found in the C major scale – which are D minor 7 – G dominant 7 – C major 7.
And if the music’s in C minor scale, you’ll create your ii – V – i from chords found in C minor scale – which are D minor 7 b5 – G minor 7 – C minor 7.
the major ii – V – I
The major scale’s ii – V – I is straightforward – just take a major scale like C major, and see which type of chord formation you get when you build a ii chord, a V chord, and a I chord using only the notes of C major scale:
The ii chord turns out as a minor 7 chord (D minor 7).
The V chord turns out as a dominant 7 chord (G dominant 7).
And the I chord turns out as a major 7 chord (C major 7).
This pattern stays the same throughout all major keys – the ii chord is always minor 7, the V chord is always dominant 7, and the I chord is always major 7.
The different types of 7th chord will be explained fully in the chords section coming up.
the minor ii – V – I
The minor ii – V – i is slightly more complicated, and often causes confusion, so let me explain.
You would expect a ii – V – i in C minor scale to be built from the notes of C minor scale (C natural minor scale):
Building a ii chord within this scale gives you D minor 7 b5 (also known as ‘D half-diminished’).
Building a v chord gives you G minor 7.
And building a i chord gives you C minor 7.
However, when you try playing these 3 chords, it doesn’t sound quite right – G minor 7 (the minor v chord) lacks drive / motivation to resolve to C minor (the i chord).
Whereas if you change the v chord from a minor 7 chord (G Bb D F) to a dominant 7 chord (G B D F), suddenly the progression comes to life and sounds much stronger. And this is how the minor ii – V – i is played (without exception):
The same applies to a complete circle of fifths in the minor scale – all chords will be built from the notes of C natural minor scale, apart from the V7 chord (2nd to last chord) which is always played as a dominant 7 chord instead:
This pattern stays the same throughout all minor keys – the ii chord is always half-diminished (minor 7 b5), the V chord is always dominant 7, and the i chord is always minor 7.