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The Caug chord

Think of the Caug as the chromatic mediator between two major chords. The chord is built from C - E - G#, a textbook augmented triad. It does its strongest work in Beatles bridges and James Bond themes, where it tends to voice-lead from one major chord to the next. The Caug earns its place in the progression. An uncanny chord, used in James Bond themes and the bridge of Oh Darling. Voicings on both instruments, theory in plain language, progressions in multiple keys and a handful of real song references are all laid out below.

Hear the Caug in the chord builder →
Scale degrees Note names

Voicings for Caug

Common ways to grip the Caug on guitar and piano. Guitar diagrams read low E to high E left-to-right; an × means muted, an open circle above the nut means an open string. Filled dots are fretted notes.

Guitar , full chord shapes

CAGED-derived voicings for Caug across the neck. Pick the shape closest to where your hand already sits.

Guitar: A-string aug at fr.3
Notes: C - E - G# (chord tones)
Guitar: E-shape aug at fr.8
Notes: C - E - G# (chord tones)
Guitar: D-string aug at fr.10
Notes: C - E - G# (chord tones)
Guitar: top-4 voicing
Notes: C - E - G# (chord tones)
Guitar: high top-4 voicing
Notes: C - E - G# (chord tones)

Guitar , triad shapes

Three-note triad shapes on each string set, shown moving up the neck. Light textures for arpeggios, pop layering and chord-melody work.

Triad: top strings (G-B-e) · open
Notes: top-string triad, open
Triad: top strings (G-B-e) · fr.4
Notes: top-string triad, fr.4
Triad: top strings (G-B-e) · fr.8
Notes: top-string triad, fr.8
Triad: middle strings (D-G-B) · fr.1
Notes: middle-string triad, fr.1
Triad: middle strings (D-G-B) · fr.5
Notes: middle-string triad, fr.5
Triad: middle strings (D-G-B) · fr.9
Notes: middle-string triad, fr.9
Triad: bass strings (A-D-G) · fr.1
Notes: bass-side triad, fr.1
Triad: bass strings (A-D-G) · fr.5
Notes: bass-side triad, fr.5
Triad: bass strings (A-D-G) · fr.9
Notes: bass-side triad, fr.9

Piano voicings

Root position and inversions. The bass note matters: each inversion changes how the chord sits under a melody.

Piano: root position
Notes: C - E - G#. Root C at the bottom. The classic stacked-thirds spelling of a augmented triad.
Piano: first inversion
Notes: E - G# - C. E at the bottom. Common in chord-melody, walking bass lines and gentler voicings.
Piano: second inversion
Notes: G# - C - E. G# at the bottom. A floating, suspended feel often used in hymns and ballads.

The theory behind Caug

Caug is a augmented triad built on C. Its three or four notes (C - E - G#) sit a specific distance apart: root, major third, augmented fifth. That makes it a passing chord in the key of a closely related major key, and the same chord works as the passing chord in a closely related major key. The simplest rule of thumb: the Caug wants to resolve up a half-step into the next major chord.

Progressions that use Caug

Short progressions that put the Caug to work. Each one is shown in a different key so you can pick the one that suits your singer.

IIVV key of C major
Caug (as passing colour)

This chord appears as a borrowed or passing chord in many major-key progressions.

→ Build this in the chord builder

Songs that feature Caug

Real records where this chord does structural work. No lyrics quoted, just the title and artist so you can pull up a copy and hear it in context.

Related chords

Chords a step away from the Caug in the songwriting circle, the natural neighbours when you want a substitution.

Keys where Caug lives

The keys where this chord turns up diatonically. Open any key page for the full set of progressions that lean on it.

Related references

Other ways to put the Caug to work across the reference library.

More songwriting tools

Got the chord but still wrestling with the lyric? Find the right rhyme in RhymeForge, or break a writer's block with the unexpected word-pair generator in CollisionLab. Need to map a full progression? The chord builder on the home page is where the Caug fits into context. All free, no signup.

About the chord builder

The Undercover Zest chord progression builder is a free interactive tool that maps every diatonic and borrowed chord in every key. Click a Roman numeral to hear it, drag chords into a progression, then audition voicings, inversions and tensions until the song clicks.

This page is a static reference for the Caug. For interactive playback, voice-leading hints and substitution suggestions, open the chord builder above.