Section 21.1 Augmented Sixth Chords
Augmented sixth chords are a special class of pre-dominant chords with notes that approach the dominant (\(\hat{5} \)) from a half-step below (♯\(\hat{4} \)) and from a half-step above (♭\(\hat{6} \)) simultaneously.
In minor, ♭\(\hat{6} \) doesn’t require a flat because \(\hat{6} \) is lowered in the minor key signature.
