In Western classical music theory, there are three groups of “harmonic areas,” that being:
Jazz theory expands upon this by assigning a specific chord/function to each of these harmonic areas:
- I for Tonic
- ii for Pre-dominant
- V for Dominant
Not only do these chords and types word as specific harmonic areas, but they can also be used as diatonic passing chords in certain harmonizing situations.
That being said, it seems a bit boring that music is reduced down to the I, ii, and V chords. What about the other diatonic chords? Do they fit any purpose?
Well, here comes the idea of plurality – that because certain chords share multiple notes with each other, that they can be interchangeable. Take a look below:
See how both the iii and vi chord can function as a tonic I. Plus, the IV works as a pre-dominant because it shares a lot of chord tones with ii. And vii is interchangeable to V.
So now, we can potentially revise this as:
- I , iii , and vi for Tonic
- ii and IV for Pre-dominant
- V and vii for Dominant
Thank you so much for taking the time to read! Feel free to comment, share, and subscribe for more daily tips below! Till next time.