Jazz Building Blocks – Part 1

In this five part series we will be getting a foot into the doorway of jazz music. Jazz, and its theory has been something that I found really difficult to get into on my own so I wanted to write a series that would help give people the basics. This week we’re looking at major ii-V-I progressions:


This 5 part series looks at the basic building blocks of Jazz theory. It follows on from the ‘Using Dominants’ series, which ended with the V on V theory. This is by no means everything you need to know about Jazz harmony, but it will get you started and help you make sense of some of the jazz standards.
This week, we’re going to be looking at major ii-V-I progressions and over the next few weeks we’ll be putting them together with other progressions to help understand some of the jazz repertoire.


We’re in C:


I         ii           iii      IV      V       vi       vii

C∆  Dm7  Em7  F∆  G7  Am7  Bø  (∆ = major 7 or major 9 and ø = half diminished)


I’ve put some guitar chord shapes at the bottom in case any of these are new, plus a little explanation into the half diminished chord.


So, a ii-V-I progression in C major is:

ii          V       I

Dm7  G7  C∆


We’re getting further inside the V on V theory. D is a fifth away from G, and G is a fifth away from C (V on V). This particular progression, and the idea of moving a fifth away from each other will come up again and again as we start to look into different standards.
Next week, we’ll look at minor ii-V-i progressions and then start getting into some actual tunes. Between now and then, get these ii-V-I chord progressions under your belt, practice them in different keys so we can hit the ground running next week:


Dm7   G7   C∆
e x      x      x
b 10    8      8
g 10    10    9
d 10    9      9
a x      10    x
e 10    x      8


Dm7   G7   C∆
e 5      3      3
b 6      3      5
g 5      4      4
d 7      3      5
a 5      5      3
e x      3      x


Guitar Chords:


C∆     Dm7   Em7   F∆     G7     Am7    Bø
e x       5       7        8        10       x        x
b 8       6       8        10      12       5       6
g 9       5       7        9        10       5       7
d 9       7       9        10      12       5       7
a x       5       7        8        10       x        x
e 8       x       x        x         x         5       7


What the heck is a half-diminished?


A half diminished chord is the same as a minor 7♭5 chord. Let’s break this down:
A straight A minor 7 chord is:
1   3   5    7
A  C   E   G   (chord shape for guitar is in the diagram above)


Now if we flatten the 5th (E) by lowering it by a semitone (or one fret) then that note becomes an E♭ and the chord becomes an A minor 7♭5:


1   3 ♭5    7
A  C  E♭  G


Am7♭5 / Aø – two different voicings


e x   x
b 4   13
g 5   12
d 5   13
a x   12
e 5   x


So why is it called a half diminished? Well, chord 7 in standard Western harmony naturally forms a diminished triad:


We’re in C major, where chord 7 is Bº:
                          1       3   ♭5
C  D  E  F  G  A  B  C  D  E  F  G  A  B  C


So the fifth has been flattened/diminished, which is why it’s called a diminished chord. Now, in Classical music, when the diminished chord is extended to a 7th, they diminish/flatten the 7th note as well as the fifth note. So, if you look at the diagram above, the natural match for the 7th would be an ‘A’, but they diminish/flatten it so it becomes an ‘A♭’:


         1  3 ♭5 ♭7
Bº7 – B  D  F   A♭


In jazz music, generally when they extend chord 7 to a diminished 7th they DON’T diminish the 7th. They keep the 7th as it would logically appear (in the diagram above it would be an ‘A’). Therefore, having only diminished the fifth note and not the seventh as well, it has been given the name ‘half-diminished’. So, you’re more likely to hear the term ‘half diminished’ rather than ‘minor 7♭5’ because it’s simply a lot shorter and easier to say!

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