Mastering Secondary Dominants: A Comprehensive Guide to Chromatic Harmony

Secondary dominants are dominant-function chords that resolve to a diatonic chord other than the tonic, temporarily tonicizing that chord and adding chromatic color to a progression. They are a cornerstone of functional harmony, used extensively in classical, jazz, and popular music to create forward motion and emotional intensity.

Etymology / Origin

The term “secondary dominant” emerged in 19th-century music theory, rooted in the concept of “applied dominants” from German Zwischendominante. Hugo Riemann and other theorists formalized the idea of temporarily treating a diatonic chord as a new tonic, borrowing its dominant. The practice itself dates back to the Baroque era, with composers like J.S. Bach using secondary dominants to enrich chorale harmonizations. The term reflects the chord’s function: a dominant (V) of a scale degree other than the tonic, hence “secondary.”

How It Works

A secondary dominant is a major triad or dominant seventh chord that is not diatonic to the current key but functions as the V (or V7) of a diatonic chord. For example, in C major, the chord D major (D–F♯–A) is the V of G (the dominant of the dominant, written V/V). It contains an F♯, which is not in C major, creating a chromatic pull toward G. The secondary dominant typically resolves to its target chord, often a major or minor triad, and can be extended with sevenths (e.g., D7 = V7/V). The voice leading involves the chromatic note (the leading tone of the target chord) resolving upward by half step, while the seventh (if present) resolves downward. Secondary dominants can be applied to any diatonic chord except the diminished vii° (which cannot be tonicized) and the tonic itself (which would be a primary dominant).

Notation & Diagrams

In Roman numeral analysis, secondary dominants are notated as V/x or V7/x, where x is the target chord. For instance, in C major:

• V/ii = A major (A–C♯–E) resolving to D minor (ii).
• V7/IV = C7 (C–E–G–B♭) resolving to F major (IV).
• V/vi = E major (E–G♯–B) resolving to A minor (vi).

Chord charts often use slash notation: D/F♯ is not a secondary dominant but a first inversion; a secondary dominant is labeled as “V/ii” or simply “A7” if the context is clear. In lead sheets, you might see “A7 → Dm” in the key of C, indicating a secondary dominant to the ii chord.

Step-by-Step / How to Play

1. Identify the target chord. Choose any diatonic chord in your key (except vii°). For example, in G major, target the ii chord (A minor).
2. Build the dominant of that target. The dominant of A is E major (E–G♯–B). Add a seventh for extra pull: E7 (E–G♯–B–D).
3. Insert the secondary dominant before the target. Place it on a weak beat or as a passing chord. Example progression: G – E7 – Am – D7 – G.
4. Resolve the chromatic tones correctly. The leading tone (G♯) moves up to A; the seventh (D) moves down to C♯ (if resolving to A major) or stays common (if to A minor, D is already in the chord).
5. Experiment with inversions. Use first inversion (e.g., E7/G♯) to smooth bass motion.
6. Chain secondary dominants. Create a sequence: C – A7 – D7 – G7 – C (V7/ii → V7/V → V7 → I).

Common Variations

• Secondary Leading-Tone Chords: Instead of V/x, use vii°/x (diminished) or viiø7/x (half-diminished). E.g., in C major, F♯dim7 (vii°7/V) resolves to G.
• Secondary Dominant of Minor Targets: When targeting a minor chord, the secondary dominant is still a major triad or dominant seventh, but the resolution may involve a deceptive cadence (e.g., V/vi → IV/vi).
• Extended Secondary Dominants: Add ninths, elevenths, or thirteenths for jazz color (e.g., D13 = V13/V in C).
• Chromatic Mediant Relationships: Secondary dominants can be used to approach chords a third away, blurring the line between tonicization and modulation.
• Sequential Patterns: Circle of fifths progressions often employ a chain of secondary dominants (e.g., E7–A7–D7–G7–C).

Common Mistakes

• Overuse: Too many secondary dominants can obscure the key and sound aimless. Use them sparingly for emphasis.
• Incorrect Voice Leading: Failing to resolve the leading tone or seventh properly can create awkward leaps or parallel fifths.
• Mislabeling: Confusing a secondary dominant with a borrowed chord or modulation. A secondary dominant is a brief tonicization, not a key change.
• Ignoring Style: In some genres (e.g., folk, simple pop), secondary dominants may sound out of place. Adapt to the musical context.
• Forgetting the Target: A secondary dominant must resolve to its implied target; otherwise, it becomes a non-functional chromatic chord.

Notable Examples in Songs

• “Yesterday” – The Beatles (V/vi in F major: D7 → Gm)
• “Autumn Leaves” – Joseph Kosma (V7/IV in G minor: C7 → Fm)
• “Can’t Help Falling in Love” – Elvis Presley (V/vi in D major: B7 → Em)
• “All of Me” – John Legend (V/ii in Ab major: Bb7 → Ebm)
• “Fly Me to the Moon” – Bart Howard (chain of secondary dominants: E7–A7–D7–G7–C)
• “Hallelujah” – Leonard Cohen (V/vi in C major: E7 → Am)