Reharmonization Techniques using Mapping Tonal Harmony Pro - 5. Secondary Dominants / Secondary Functions

Secondary functions are simply chords that belong to the map of a diatonic function other than I

So if we are in C, the I is C, the IV chord would be F and the V7 chord G7.

F is then a diatonic chord in the key of C

Let's say we are now in the key of F then F is the I now (let's not forget that it was the IV when we were in C). Now, in our new key of F, F is the I, Bb is the IV and C7 is the V7

There's no C7 chord in the key of C but C7 it the V7 in the key of F

When viewing this C7 from the key of C we then see it as the V7/IV (Five seven of four), which we call a Secondary Function

In Mapping Tonal Harmony Pro the secondary functions appear on level 4 of the map and they are shown next to their respective diatonic function

Here's the video lesson on how to use Secondary Functions in reharmonization

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