# Diffrence between Polychords and Extended chords

I'm really curious about the difference between polychords and extended chords. I know a polychord is two chords played at the same time where there is a higher chord and a lower chord. The common example I see C/Dm when a polychord is demonstrated, however the way I look at is just a Dm11 chord that is voiced with a closed position Dm in the lower octave and a closed position C in the higher octave.

Is there a more distinctive difference between polychords and extended chords or are they just specially voiced extended chords?

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​​​​​​​​​​​​​​If I have a sequence of notes as a chord, say, `C# E G B`, I could call that chord Em6 or C#m7b5 (or even C#dim#7). For most series of notes there will be multiple ways you can notate it. It's the same thing with polychords - polychords can be notated as extended voiced chords (e.g. Db/G = G7#11b9) if you want, but sometimes the polychord notation is just easier to read at a glance. –  Lilac Sep 3 at 7:04

The polychords use a fraction for a symbol, like: , so as to distinguish from the slash chords.

From what I have understood, the point of the polychords is to help the player read and play faster. It is easier to read Abm (fraction) G7 rather than G7b9b13. The following chord can be called both G7b9b13, and Abm (fraction) G7b9b13.

(I know that someone can say -- Hey, just practice and you'll be able to play it -- but, it exists)

Quoting Jazzology page 15 (Chapter 2):

In practice, jazz pianists and arrangers prefer simplifying upper-structure notation so as to make the chords easy to read and play.

According to the Wiki article on Polychords, it is also used for bitonality or polytonality.

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You are right that in principle there's no difference other than that a polychord has two complete triads, which is of course not necessary for a general extended chord. Obviously, polychords are related to upper structure triads. I would say that polychords are a special case of extended chords which contain two complete triads. The main advantage is a notational one. A polychord is a simple notation for a complex chord structure.

BTW, note that polychords do not necessarily consist of two triads in closed position as you seem to imply in your question.

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