A “5 of 5” chord is a secondary dominant — specifically, it’s the dominant (V) chord of the dominant (V) chord in a given key. In Roman numeral analysis, it’s written as V/V, meaning “the V of V.”
How it works:
- In any key, the dominant chord (V) is built on the 5th scale degree.
- The 5 of 5 (V/V) is the chord that functions as the dominant of that dominant.
Example in
C major
- The V chord in C major is G major (G–B–D).
- The V of G is D major (D–F#–A).
- So, the 5 of 5 in C major is D major, and it’s written as V/V.
Even though D major isn’t diatonic to C major (it contains F#, which is not in C), it temporarily borrows from the key of the dominant (G major) to create stronger tension and drive toward G, which then resolves to C.
Function:
- V/V resolves to V, which then resolves to I.
- It’s used to create stronger forward motion or a temporary tonicization of the dominant chord.
Summary:
- 5 of 5 = V of V = V/V
- In C major:
- V = G
- V/V = D
-
So: D → G → C
Let’s take a look at C Major chord on the treble staff…
Now on the keyboard…
If you’re in the key of C Major this is the I Chord.
The fifth degree of the C Major scale is the note G.
If you build a major chord on the note G that’s G Major. This is the five chord. Let’s see that on the treble staff and the keyboard…
The fifth degree of the G Major scale is the note D. If you were to build a D Major chord off the note D it would look like this…
So the 5 of 5 chord in G Major is D Major.
You can literally build the five of five chord on any note chord across the keyboard.
Many classical composers used secondary dominants like the 5 of 5 (V/V) to create harmonic tension and variety. Here are some well-known examples of classical pieces that use V/V chords:
1. Beethoven – Piano Sonata No. 8 “Pathétique”, 2nd Movement
- In this lyrical movement, Beethoven uses secondary dominants including V/V to momentarily tonicize other chords and create smooth modulations.
- Example: In the key of Ab major, you’ll hear E major (V of A, which is the V of D — a chain of secondary dominants) used for color and tension.
2. Mozart – Sonata in C Major, K. 545, 1st Movement
- This deceptively simple sonata frequently uses V/V chords.
- In C major, D major is V/V. It shows up briefly to lead to G (V), and then back to C (I).
- Listen for a D major chord (D–F#–A) leading to G major, particularly in the development and recapitulation sections.
3. Bach – Prelude in C Major (WTC Book I) BWV 846
- Bach uses a series of secondary dominants throughout, including V/V, to create harmonic movement within the diatonic framework.
- Around measure 22, there’s a D major chord in C major functioning as V/V, resolving to G major (V).
4. Haydn – Symphony No. 104 “London”, 1st Movement
- Haydn regularly uses V/V chords in his transitions and modulations.
- In the key of D major, a chord like A major is V, so E major is V/V — and you’ll hear it driving the music toward the dominant key area in the exposition.
5. Schubert – Impromptu in G-flat Major, Op. 90 No. 3
- Schubert uses rich chromaticism including V/V chords to guide the music’s harmonic direction.
- For example, in G-flat major, he uses D-flat major (V), and A-flat major (V of D-flat) appears as a V/V.
Until next time practice building five of five chords.