Chord Rudiments

Some important clarifications

(1) The chords listed above are those commonly found in tonal music, rather than those theoretically (or abstractly) derived from the major and harmonic minor scales respectively.

In particular, for minor keys, note that

a. III⁺ is excluded even though it is derivable from the harmonic minor scale; this is because it is not used as a structural chord by tonal composers.

b. ^(b)VII is included even though it is not derived from the harmonic minor scale; again, it is because this is what tonal composers commonly used in minor-key passages.

As such, not all the minor-key chords are derived from the natural minor scale either. Most notably, chords V, vii^o, vii^o7 (in bold print) are dominant-function chords which play an essential role in defining the tonality; they are not derived from the natural minor scale (all the other chords listed for the minor key are).

(2) For both major and minor keys, vii^o7 (a dominant substitute chord) is a full-diminished seventh chord (i.e. a diminished triad with a diminished 7^th added). In minor keys, adding a seventh to ii^o yields a half-diminished seventh chord ii^Æ7 (i.e. a diminished triad with an added minor 7^th).

Figured-bass Figures and Chord Inversions

It is also important that you are familiar with the representation of chord inversions using figured-bass figures.