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The Gdim chord

The Gdim (G - A# - C#) is a diminished triad, which is why it sounds the ragtime piano grease. Writers pick it for a moment of unease, and you can find it across early jazz and the Great American Songbook. On guitar the chord sits in barre-chord territory for most useful keys; on piano it stacks straight up under the right hand. The page below covers the voicings worth memorising, the theory, the progressions where the Gdim earns its keep, and the records that lean on it.

Hear the Gdim in the chord builder →

Voicings for Gdim

Common ways to grip the Gdim 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 Gdim across the neck. Pick the shape closest to where your hand already sits.

Guitar: A-string dim at fr.10

Notes: G - A# - C# (chord tones)

Guitar: D-string dim at fr.5

Notes: G - A# - C# (chord tones)

Guitar: top-4 voicing

Notes: G - A# - C# (chord tones)

Guitar: high top-4 voicing

Notes: G - A# - C# (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) · fr.2

Notes: top-string triad, fr.2

Triad: top strings (G-B-e) · fr.6

Notes: top-string triad, fr.6

Triad: top strings (G-B-e) · fr.9

Notes: top-string triad, fr.9

Triad: middle strings (D-G-B) · fr.2

Notes: middle-string triad, fr.2

Triad: middle strings (D-G-B) · fr.6

Notes: middle-string triad, fr.6

Triad: middle strings (D-G-B) · fr.11

Notes: middle-string triad, fr.11

Triad: bass strings (A-D-G) · fr.3

Notes: bass-side triad, fr.3

Triad: bass strings (A-D-G) · fr.6

Notes: bass-side triad, fr.6

Triad: bass strings (A-D-G) · fr.11

Notes: bass-side triad, fr.11

Piano voicings

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

Piano: root position

Notes: G - A# - C#. Root G at the bottom. The classic stacked-thirds spelling of a diminished triad.

Piano: first inversion

Notes: A# - C# - G. A# at the bottom. Common in chord-melody, walking bass lines and gentler voicings.

Piano: second inversion

Notes: C# - G - A#. C# at the bottom. A floating, suspended feel often used in hymns and ballads.

The theory behind Gdim

Spell out the Gdim and you get G - A# - C#. The intervals from the root are root, minor third, diminished fifth, which is the recipe for a diminished triad. In Ab major the chord plays the role of Leading tone (vii°); in F minor it shows up as Supertonic (ii°). Its preferred next move is resolve up a half-step or down to the I, which is what makes it useful in ragtime and jazz.

Progressions that use Gdim

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

i→iv→V key of A minor

Gdim (as passing colour)

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

→ Build this in the chord builder

Songs that feature Gdim

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 Gdim in the songwriting circle, the natural neighbours when you want a substitution.

TriadG DomG7 Maj7Gmaj7 m7Gm7 NeighbourD NeighbourDm NeighbourD7 NeighbourC

Keys where Gdim lives

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

Ab major F minor

Related references

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

Arpeggiooutline it with arpeggios

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 Gdim 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 Gdim. For interactive playback, voice-leading hints and substitution suggestions, open the chord builder above.