Ihave a theory text book that has a chapter on chord extensions but it also has 2 chapters on species counterpoint. I dont get how its supposed to work together? For example you should only use maj min 3rds and maj min 6ths and perfect octaves and 5ths and avoid 2nds and 7ths on downbeats.. so where does a 9th chord tone fit in all this??


2 Answers 2


You have certainly heard that there have been two different aspects and directions in the development of harmony: polyphony and chord theory.

In counterpoint and cantus firmus there are no gaps provided like intervals as 7th, 9th or 11th. As this rules and theory have been developed for the voice leading of singing monks and not primary for instruments. And mind that the theory follows the praxis. So later the rules have been applied also for keyboard music and other instrument ensembles that allowed extended chords and bigger intervals. But in the basic theory of the c.p. species the rules remained the same.

These extended chords are components of a different and younger theory and is not compatible with the original c.p. - theory. But it is possible to adapt it and integrate it.

(I haven’t read yet Benward/Saker but I think they teach the two theories independent of each other.)


Like Athanasius says, we can find already intervals of a 9th in c.p. practice:

The fourth species, often called syncopation or ligature, consists of tied notes over nearly every bar in the counterpoint, creating a syncopated effect with the cantus fi rmus. Many of the tied notes are suspensions. B./S. p.163/64

  • thanks for the answer Albrecht Hugli! could you recommend a good book that is centered on the younger chord theory?
    – Gordon O
    Commented Apr 18, 2020 at 22:02
  • Diether de la Motte: Harmony. In his Counterpoint he says: no more species! Commented Apr 19, 2020 at 6:06

I agree with Albrecht's answer, but I'll just add a few thoughts:

Species counterpoint was never meant to be a practical composition method. It was a pedagogical device gradually invented in the 1600s and early 1700s. Its rules are all sort of artificial, but meant to teach ideas that could have use in practical composition. If you've seen The Karate Kid, I'd liken it to "wax on, wax off" -- waxing a car doesn't really teach you karate, but it might create muscle memory and strength that could be adaptable to a real-world scenario (I suppose). Or, for a different analogy, the world of species counterpoint is kind of like the artificial world of physics problems that often assume no friction, no air resistance, perfect spheres or point masses, etc. Those simplifications help students to solve problems and learn concepts before they advance to the complexities of the "real world."

Ninths happen in the real world, and they even happened at the time when species counterpoint was formulated. But back then, they had a lot of rules around them. To theorists in the 1700s, a "ninth chord" was generally a chord that had a suspension, typically what we'd think of today as a 9-8 suspension. There were rules about where it could occur rhythmically and how it had to resolve. (And it's actually part of species counterpoint: specifically fourth species, which teaches suspensions. "11th chords," as they were understood in the 1700s, also occur there in 4-3 suspensions. Fifth species also allows these to be used.)

The main thing that happened with "extended" tertian chords is that those notes built above the triad (including the 7th, as well as the 9th, 11th, 13th) came to be used a little more freely, without always adhering to the "rules" of counterpoint. Traditionally, the 7th always resolved down by step, as typically did the 9th and 11th. A modern 9th chord occurring in certain jazz or pop styles might also tend to have the 9th resolve down by step in its voicing (particular in a "flat-9" chord). That ultimately comes from the 9-8 suspension context that would have been part of the rules of species counterpoint. But 9ths can sometimes go other places now in modern styles, as can the other "extensions."

Ultimately, the question seems to be wondering how/why these two somewhat incompatible notions are in the same theory textbook. And the answer to that one is a practical pedagogical one: some modern music theory professors still feel that "species counterpoint" is a useful "wax on, wax off" sort of exercise for students, even though it was never a practical composition method. Other theory professors skip most of it. On the other hand, chord extensions are an important part of romantic period music as well as modern pop and jazz theory. The textbook is just trying to "cover all bases" and give different pedagogical tools and perspectives, not necessarily presenting a single coherent theory for only one musical style.

  • Why the downvote? Somebody doesn't like The Karate Kid?
    – Athanasius
    Commented Apr 19, 2020 at 3:43
  • great answer! i did not down vote you.. thanks for the added input on the matter.
    – Gordon O
    Commented Apr 19, 2020 at 4:59
  • Your example of karate kid and physic labor experiments are good comparisons. The introduction of 9th and 11th chords by suspensions is also true.. Commented Apr 19, 2020 at 5:51

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