Sevenths
G diminished 7th chord
Symmetrical and very tense — every note is a minor 3rd apart.
Gdim7 is the vii°7 chord in G♯ minor.
- Notes
- GB♭D♭F♭
- Formula
- 1♭3♭5𝄫7
- Built from
- root · minor 3rd · diminished 5th · diminished 7th
How to play Gdim7
About the G diminished 7th chord
Playing it
On guitar, Gdim7 has an open-position shape, 312020, using four fingers alongside the open strings.
On piano, Gdim7 has two black keys (B♭ and D♭) and two white keys.
On ukulele the usual Gdim7 shape is 0101, using two fingers.
Related chords
Take away the root and the other three notes form B♭dim (B♭ D♭ F♭) — so you can think of Gdim7 as B♭dim with G added underneath.
Gdim7 is symmetrical — its notes are evenly spaced — so C♯dim7, Edim7 and B♭dim7 contain exactly the same notes. There are only three different-sounding diminished 7th chords in all.
Move a single note and Gdim7 becomes a different chord: drop the F♭ for Gdim, raise D♭ to D for Gm6 and raise F♭ to F for Gm7♭5.
Where you’ll hear it
Notice the F♭ in Gdim7 (G B♭ D♭ F♭): each note of the chord takes its own letter (G–B–D–F), so the diminished 7th has to be written F♭ rather than E — the same key on a piano, spelled to fit the chord.
