# Parallel chord substitutions

Are parallel chord substitutions common in (classical) music (if so, please share some examples)? And do they have the same function as the original chords?

By saying parallel chords I am referring to the term Hugo Riemann used in his theory (Parallelklang in German). For example, in the key of C major (minor), the parallel chords for each chord degree are:

``````  I: A minor (Eb major)
ii: F major (diminished, so none?)
iii: G major (C minor)
IV: D minor (Ab major)
V: E minor (Bb major)
vi: C major (F minor)
VII: diminished, so none? (G minor)
``````

Since any parallel chord for each chord degree is in the key of C major or C minor, I won't talk about them much (`*`).

But I was wondering, what if we use the parallel chord of, say, the Neapolitan, e.g. Bb minor, in the key of C? For example, instead of having the usual chord progression: `I-iiN-V`, we'd have: `I-(iiN)p-V`, where (iiN)p is the parallel chord of the Neapolitan, Bb minor. Please note that I am referring to `V` as function, so it could be `V`, `V7`, `V+`, `VII7` (diminished or not), etc.

And also, what about secondary dominants? For example, in C major:

`````` V/ii: F# minor (instead of A major)
V/iii: G# minor (B major) (the same applies to the V/III)
V/IV: A minor  (C major)
V/V: B minor  (D major)
V/vi: C# minor (E major)
``````

`*`I'd like to mention that, while writing the first table, I realized that the parallel chord of II is IV, and vice versa. Since we know that these two chords share the same function, does this answer my very question? Does this apply to the parallel chords of the "chromatic" chords as well (the Neapolitan and the various double dominants)?

However, interestingly, this does not apply to minor scales. For example, in C minor, the parallel chord of `i` is not Ab major (`VI`), etc.

• There's a slight confusion in terms. In German, I believe, the term parallel is used to mean relative - and that's where this question is going. The majority, I believe, is used to the term parallel to mean 'having the same root note, or home'. So, it may benefit the question to use the term 'relative' rather than parallel.
– Tim
Commented Jan 12, 2019 at 14:31

In your key of C major, the ii is the Parallelklang (what we call "relative key" in English) of IV, and vice-versa. And since those two chords both function as predominants, we do see a kinship between the two harmonies.

It's a similar story with I and vi: vi, the Parallelklang of I, often substitutes for I, especially at deceptive cadences where V moves to vi instead of to I. In more advanced tonal music, you'll occasionally see iii substituting for V, and those keys have the same relationship.

But while this is true, I think it's more important to realize that these two Parallelklang-related triads share 2 of 3 tones: C major and A minor both have `C E`, F major and D minor both have `F A`, and G major and E minor both have `G B`. In my mind, it's this relationship that allows these substitutions to occur. The fact that they are relative keys is, to me, less important and more coincidental than the statement "a chord that is 2/3 the same as another chord will in some sense sound similar." (Note also that the remaining pitch is only one whole step away from the pitch in the other triad.)

Looking at your second chart, I think you'd be really interested in reading about Neo-Riemannian music theory. As its name implies, it renews Riemannian ideas to help explain chord progressions that would be considered non-standard in tonal music. Just be aware that it was created by American scholars, so their terminology is based on the English language; this means that C major and A minor are relative keys while C major and C minor are parallel keys. Confusing, huh? :-)

• @ richard: this is a wonderful example that to find a good answer is to ask a good question. if only all user would do this like george ;) Commented Jan 12, 2019 at 11:41
• Truth is that I am very interested in Neo-Riemannian theory, although I feel I am not ready yet to start studying it. Currently, I am reading Schoenberg's "Structural Functions of Harmony", and maybe after that I will start going through Neo-Riemannian textbooks (I really like John Adams's music, so that would motivate me more!). Regarding parallel and relative, in Greece we use the word σχετικός (=relative) to describe relative keys. But I checked the Wikipedia article that says parallel, so I used that instead (en.wikipedia.org/wiki/Parallel_and_counter_parallel). Commented Jan 12, 2019 at 13:19
• @AlbrechtHügli - welcome to the site. It appears that you've been round the block a few times, and will be an interesting and useful contributor to this site. Be aware that a lot of the questions posed here are from beginners, thus will be basic and probably not couched in some of the terms that some of us use day to day. We just need to help them on their journey, and eventually, they'll help the next generation in turn - I hope! In the meantime, immerse yourself in the diversity of questions (and answers like Richard's!). Sometimes it's like Pandora's box!
– Tim
Commented Jan 12, 2019 at 14:43
• @George If you know how to build/identify triads and seventh chords, then that's actually all you need to know to learn Neo-Riemannian Theory. (Not that I'm trying to force you to learn it, I'm just letting you know!) Commented Jan 12, 2019 at 17:06