Secondary Leading Tone

The most unique triad in the major key is the diminished leading tone triad. Since it is the only diminished triad in major and because it contains the tritone, it is the chord that most effectively allows you to hear the tonic. By constructing a leading tone triad before any major or minor triad, you can temporarily tonicize (establish a certain pitch as the tonic) that chord root. Since we are temporarily creating a new sense of tonic, the functions of the tritone should resolve in relation to that tonic (7-1, 4-3).

Note that these secondary leading tones can be looked at as altered diatonic chords:

This ends up being a sloppy way to analyze because it starts to break down the functional relationships that RNA implies. It also ignores the temporary tonicization that is created.

Secondary leading tone chords are analyzed by adding a slash between the leading tone triad (vii°) and the following major or minor triad. The slash stands for the word ‘of,’ so you would reading vii°/V as ‘diminished seven of five,’ or ‘leading tone of five’:

Major:

Selected examples in minor:

Secondary Dominant

The dominant triad can also be used to tonicize any major or minor chord. A secondary dominant triad is a major chord that is constructed a fifth above a diatonic major or minor chord. These are also notated with slashes. V/ii would be read ‘five of two.’

Major:

Note that every secondary dominant in major (with the exception of V/IV) requires a chromatic alteration.

Selected examples in minor:

Secondary Dominant Seventh/Leading Tone Seventh

The combination of a secondary dominant and leading tone triad creates an even stronger tonicization of any major or minor triad.