Chim Chim Cher-ee has a fantastic chord structure:
i, IIIaug, III, IV, iv, i, II7, V
Most of those transitions make sense to me. However, there are three transitions that I don't quite understand:
i to IIIaug,
IIIaug to III, and
IV to iv.
All of these make the moving baseline nice and smooth (down a half step every measure). That said, I can't just make a song that has a the same baseline, and just choose any chord on top of it, and have it sound nice.
Why do those transitions work? Is the
IIIaug not really a chord, and simply a moving note? Why is going from Major to minor fine here, and are there other spots that this transition is fine?