Theory - From Classical To Jazz - Part 2

Assuming you have read Part 1, or have some knowledge of music theory, consider the chord shown above and answer this question - what chord is it?

Savvy musicians will realise immediately that the name of the chord will depend entirely on the context in which it is being played - this might be a E7 with a raised 3rd, or an inversion of a Asus4 or Dsus2. Or maybe some notes from the overall chord are missing (because they are being played by other instruments). So exactly what chord this is, is not clear.

In Mark Levine's excellent volume "The Jazz Piano Book", this chord appears under the notation C∆.

Now you may be wondering how this could be a C major 7th chord - doesn't C∆ look like this?

The chord at the top does not have the C (root), G (5th) or B (7th) - the only note in common is the E (3rd). How can this be a 7th chord without the 7th in it?

The answer lies in the fact that in jazz, musicians will often substitute one chord for another or add other notes to chords to get a richer sound or one with more 'bite'.

The chord at the top is not a major 7th, it's a 6-9 chord. A very typical thing in jazz (on piano, at least) is to omit the root (the bass player will be dealing with that, or you as the pianist may be playing it on your left hand) and also the 5th - since all major and minor chords have the 5th, it is the 3rd and other extensions (7ths, 9ths, etc.) that determine the quality of the chord, so the 5th does not matter as much.

In his book, Levine says "you can usually substitute the 6th and 9th for the major 7th". Hence the chord at the top.

So what is this chord?

This appears in Levine's book under the notation G7. Looking carefully at it, we can see the 3rd and 7th of a G7 chord, but the 6th and 9th have been added.

For me, with my background in classical and rock, this was illuminating to say the least. In classical piano, you don't have chord symbols, you play the notes that appear on the score. In rock, if the notation on the score is 'G7', you play a G7 chord. But in jazz, you are not so restricted - you can add to chords, substitute one kind of voicing for another, and so on. You have lots of choices.

But... and it's no small 'but'... with this 'freedom' comes responsibility. Unless you are playing alone, whatever you are playing needs to fit with what is being played around you. If your choices are throwing off the vocalist, you won't be popular (or likely to be asked to accompany that vocalist again).

Levine suggests the following as additions to various chords:

• major 7th: raised 4th, 5th, raised 5th, 6th, 9th
• dominant 7th: 5th, 9th, flat 9th, raised 9th, raised 11th, 13th, flat 13th
• minor 7th: 5th, 9th, 11th, 6th, flat 6th (rare)

This is by no means exhaustive, but as Levine explains, some additions work against the basic sound of the chord - for example, adding the 4th or a flat 9th to a major 7th tend to destroy the tonal feeling of "major" - so they are not commonly played.

Levine also notes that the 6th is sometimes played in place of the 7th, or they can be played together.

Now consider the following snippet from an actual piece:

Note that the chord indication is F7.  The chords that actually written are F7 with the 6th and 9th added, and Eb with the 9th added (over an F base).

From later in the same piece:

The indication is C7#9, but the chord has not only the raised 9th but also a flat 13th.

To sum up - in jazz, what chord is indicated and what you actually play are not necessarily the same. There are possibilities to add to chords or substitute one voicing for another, but remember - what you play will depend on what is happening around you.