Introduction
A polychord is, as the name implies, two or more chords superimposed on top of each other. It’s written as two chords, one on top of the other, separated by a horizontal line. For example, a D Major Triad over a CMaj7 Chord would be notated as follows:
This notation is similar to that of a slash chord, so it’s important you don’t confuse the two.
There are two ways of thinking about polychords:
- You can about a polychord as a single entity or single chord.
- Or you can think about it as two separate entities or chords – and so creating a kind of polytonality.
Polychords as a Single Entity
So firstly, if we think about a polychord as a single entity, then we simply look at all the notes that comprise the polychord and infer a proper chord name. See table below for examples.
Using this approach polychords are just another way of notating a chord, which can be simpler to read. When you’re sight reading, sometimes it’s easier to think about two small chords rather than a single big chord. So you might find it easier to think ‘ah, I need to play a A6 in my right hand and a C7 in my left hand’, rather than ‘I need to play a C13♭9#11 chord’.
Using this approach, when improvising you simply play the scale or arpeggio implied by the actual full chord.
Another way of saying this is that you want to pick a scale which contains all (or almost all) the notes of the chord.
- C Lydian mode contains all the notes in the polychord D on CMaj7 – so fits well over the chord.
- C H/W Diminished Scale contains all the notes in the polychord A6 on C7 – so fits well over the chord.
Polychords as Two Entities
The second way of thinking about polychords is as two separate entities which imply a polytonality. Using this approach, when improvising over a polychord you play a scale or arpeggio that fits over each of the two individual chords.
In this way you are outlining each of the tonalities implied by the polychord – thus creating some polytonality. Now, some notes will clash, but that’s OK – polytonality is supposed to be a little bit dissonant. We are, after all, superimposing unrelated keys on top of each other.
Notating Polychords
Because polychords are just another way of writing a chord, you don’t often find them written out in lead sheets. Lead sheets generally just state a simplified version of the chord. So instead of writing and A♭Maj7 over C7 polychord, a lead sheet will often just write C7#9♭13, or C7 alt, or maybe even just C7, even if the original composer intended or played a polychord. Having said that, you will occasionally find polychords written out in transcriptions of more modern Jazz musicians, like in Windows by Chick Corea and Dolphin Dance by Herbie Hancock.
Voicing Polychords
Another thing to note is that if you play a polychord exactly as written, then you might end up with numerous doubled notes. As a general voicing rule, you want to try avoid doubling notes. So for example, if you’re playing an A♭Maj7 over C7 – you could omit the C & G in the A♭Maj7 chord because they are already played in the C7 chord.
You can also voice the notes in each chord in a polychord in any inversion and in order. They can also overlap. But you still want to generally keep the notes of each chord relatively close together, so that the polychord is still played as two separate chords. Avoid breaking up each individual chord too much.
Modern Harmony
So far, all the above examples have been polychords that only make use of available tensions. But in more ‘Modern’ or ‘Contemporary’ Jazz you also find polychords which make use of unavailable tensions and therefore create non-standard, atonal chords. So you could have polychords like:
These polychords do not obviously describe any standard ‘tonal’ chord. Neverthless, all the above rules apply here also. You can play a ‘scale’ comprised of all the notes in the polychord, even if it is not a ‘real’ scale.
Now, the ‘poly’ in polychord implies ‘many’ – not just two. So it is possible to have more than two chords in a polychord. For example you could have a:
You could even find a polychord in a slash chord – who knows?…Once you hit modern, contemporary, atonal Jazz, anything is possible. But again, they all work just the same way as I’ve described above. Either analyse all the individual notes separately and try create a regular chord, or play the implied scale for each individual chord.
Conclusion
So when playing a your next song, see if you can insert one or two polychord as a substitute for a regular chord. You can even use one of the more dissonant and interesting ones and see what happens. Try using a B over C polychord in place of a CMaj7 in a ii-V-I in C – and just see how it sounds and how you like it.
