Hi Jon, I just wanted to know if it would be functional, even if you had not gone to vi after V/vi, and would move to some other chord say V. It actually sounds pretty good to me. Thank you!
I wouldn’t consider it “functional” in the strict sense of the word. But it still works for the following reason.
The voice leading is good. Imagine we are in the key of C, the movement of E major (E-G#-B) to G major (G-B-D) have the common note of B, the G# to G is only a half-step, and the E to D is a whole-step. This is relatively little movement and so it feels smooth.
This is actually considered a chromatic median relationship. It is the same reason why C – Eb (I – bIII), C – E (I-III), C – Ab (I-bVI), or C to A works (I-VI).
Thank you Jon! 🙂