The Six-Four Chord
A six-four chord is a triad in second inversion, with its fifth in the bass. C major becomes C/G: G in the bass with C and E above it. Classical harmony treats this position according to its voice leading, so the surrounding bass and resolution tell you more than the chord symbol alone.
- second inversion
- fifth in the bass
- cadential, passing, pedal or arpeggiated
What does six-four mean?
Write C major as C-E-G and place G in the bass. Above G, C forms a fourth and E forms a sixth. Figured bass records those two intervals as 6 and 4, so the position is called a six-four chord.
The label describes intervals above the bass. It does not describe a new chord quality. C/G is still a C-major triad, but its bass position changes how it connects to the music around it.
Why is second inversion treated differently?
In classical counterpoint, a perfect fourth against the bass is treated as a dissonance that needs explanation through preparation, passing motion or resolution. In C/G, the chord root C forms that fourth above G.
This convention belongs to a style that values independent voices and directed dissonance. A guitarist can use C/G as a stable pop voicing, especially when a repeated G bass or riff establishes a different context.
Ask two questions before assigning a function: What is the bass doing, and where do the notes above it move next?
What are the four common uses?
- Cadential six-four
I6/4 appears over scale degree 5 before V. In C major, C/G moves to G or G7: C falls to B and E falls to D while G remains in the bass.
- Passing six-four
The bass moves by step through the second inversion. Play C-G/D-C/E: the bass walks C-D-E, and G/D is the second inversion of G.
- Pedal six-four
The bass stays on one note while the upper voices move away and return. The 6/4 decorates a sustained bass instead of creating a new root motion.
- Arpeggiated six-four
The bass outlines the notes of one triad, such as C-E-G, while the harmony remains C major. The second inversion appears as one position inside the arpeggio.
How does the cadential six-four work?
The cadential 6/4 looks like a tonic triad above the dominant bass, but it behaves as an embellishment of V.
In C major, play G-C-E followed by G-B-D and then C-E-G. The bass holds G through the first two sonorities. C resolves down to B and E resolves down to D before the bass finally reaches C.
For that reason, analysts often hear the first sonority as dominant function with two accented non-chord tones. The symbol I6/4 describes its spelling; the phrase position and resolution explain its function.
How do you identify the type from the bass?
| Type | Bass behavior | Typical placement | What follows |
|---|---|---|---|
| Cadential | holds on scale degree 5 | strong beat near a cadence | V, then usually I |
| Passing | moves by step | weak or connecting position | continued stepwise bass |
| Pedal | stays on one pitch | inside a prolonged harmony | return to the surrounding sonority |
| Arpeggiated | outlines a triad | inside a broken-chord pattern | another position of the same chord |
Do not identify the type from the three notes alone. The same pitch collection can perform different jobs when the bass rhythm and neighboring chords change.
Is every slash chord a six-four chord?
No. A slash chord only specifies a bass note. C/G is a second-inversion C triad because G is its fifth. C/B is not an inversion of C major because B is not part of the triad.
The slash notation also says nothing by itself about classical function. C/G may be cadential, passing, pedal, arpeggiated or simply a chosen pop voicing.
How can you hear the difference?
- Compare positionsplay C, C/E and C/G with the same upper register.
- Hold the dominant bassplay G-C-E, then G-B-D, then C-E-G.
- Walk the bassplay C-G/D-C/E and listen to D as a passing bass note.
- Keep a pedalhold G while the upper notes move G-B-D, G-C-E, G-B-D.
Keep going
Everything in harmony
- Harmonic Function
- Diatonic Chords
- Cadences
- Voice Leading
- The Six-Four Chord