Gdim7

G Diminished 7th — perfectly symmetrical stacked minor thirds — the ultimate passing chord, able to resolve almost anywhere.

The keys
C4C5C6
G – B♭ – D♭ – F♭
What's inside Gdim7
NoteInterval from rootDegree
GRoot1
B♭Minor 3rdb3
D♭Diminished 5thb5
F♭Diminished 7thbb7
Inversions
PositionKeys (low → high)
Root positionG4 – B♭4 – D♭5 – E5
1st inversionB♭4 – D♭5 – E5 – G5
2nd inversionD♭5 – E5 – G5 – B♭5
3rd inversionE5 – G5 – B♭5 – D♭6
A working voicing

Split the chord between two hands the way working players do — a solid shell low down, the colour tones up top:

HandKeys
Left (shell)G2 – E3
Right (colour)B♭4 – D♭5
Where Gdim7 lives

As the ii chord

Gdim7 → C7 → Fmaj7

Minor-family sevenths live on the ii — this is the move they were born for.

Stepwise colour

G → Gdim7 → Am7

Used as a passing colour between neighbouring chords.

Put Gdim7 under your fingers

Hear every voicing, see the keys light up, and drill it in the interactive Chord & Voicing Lab.

Open the Chord & Voicing Lab →