Section 18.1 Secondary Diminished Chords
The \(\left.\text{vii}^{\circ}{}\right.\) chord has dominant function (see the Harmonic Function Flowchart). Since chords of dominant function typically resolve to chords of tonic function, diminished triads as well as half–diminished and fully–diminished seventh chords occur as secondary diminished chords.
Below are some examples of pieces with secondary diminished chords. Notice that chromaticism is an “essential” part of secondary diminished chords (“non–essential” chromaticism refers to chromatic non–chord tones).