G diminished major 7th chord on guitar (GdimMaj7)

Also called or written GdimMaj7, GdimM7, G°M7, G augmented minor seventh or G minor seventh sharp five

G diminished major 7th is built from G, B♭, D♭ and F♯. The 3rd fret shape mutes the two highest strings and uses a compact four-fret span.

3frGD♭F♯B♭EADGBE
Positions on the neck1 of 5
Practice G diminished major 7th chord

How it is built

GRootB♭Minor thirdD♭Diminished fifthF♯Major seventh

Formula 1, ♭3, ♭5, 7

Inversions

How do you play a G diminished major 7th chord on guitar?

G diminished major 7th is played at the 3rd fret as 3 4 4 3 × ×: index finger on the low E string at fret 3, ring finger on the A string at fret 4, pinky finger on the D string at fret 4 and middle finger on the G string at fret 3. The B and high e strings stay muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)31G (1)
5 (A)43D♭ (♭5)
4 (D)44F♯ (7)
3 (G)32B♭ (♭3)
2 (B)muted
1 (e)muted

AdvancedThe pinky on the D string at fret 4 must arch cleanly over the ring finger on the A string, while the B and high e strings stay muted.

5th fret

G diminished major 7th is played at the 5th fret as × × 5 6 7 6: index finger on the D string at fret 5, middle finger on the G string at fret 6, pinky finger on the B string at fret 7 and ring finger on the high e string at fret 6. The low E and A strings stay muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)muted
5 (A)muted
4 (D)51G (1)
3 (G)62D♭ (♭5)
2 (B)74F♯ (7)
1 (e)63B♭ (♭3)

10th fret

G diminished major 7th is played at the 10th fret as × 10 11 11 11 ×: index finger on the A string at fret 10, middle finger on the D string at fret 11, ring finger on the G string at fret 11 and pinky finger on the B string at fret 11. The low E and high e strings stay muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)muted
5 (A)101G (1)
4 (D)112D♭ (♭5)
3 (G)113F♯ (7)
2 (B)114B♭ (♭3)
1 (e)muted

GdimM7/B♭ inversion · open position

G diminished major 7th is played in open position as × 1 × 0 2 2: index finger on the A string at fret 1, middle finger on the B string at fret 2 and ring finger on the high e string at fret 2. The G string rings open. The low E and D strings stay muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)muted
5 (A)11B♭ (♭3)
4 (D)muted
3 (G)openG (1)
2 (B)22D♭ (♭5)
1 (e)23F♯ (7)

GdimM7/B♭ inversion · fret 5

G diminished major 7th is played at the 5th fret as 6 × 5 6 7 ×: middle finger on the low E string at fret 6, index finger on the D string at fret 5, ring finger on the G string at fret 6 and pinky finger on the B string at fret 7. The A and high e strings stay muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)62B♭ (♭3)
5 (A)muted
4 (D)51G (1)
3 (G)63D♭ (♭5)
2 (B)74F♯ (7)
1 (e)muted

Why it sounds like that

G diminished major 7th uses the formula 1, ♭3, ♭5, 7. The diminished 5th between G and D♭ creates a tritone, and the major 7th F♯ is the leading tone. Compare it to G minor 7th flat 5th, which lowers the 7th to F.

What goes wrong with G diminished major 7th?

  • Letting the B string ring open and clash with the chord.
  • Flattening the pinky onto the G string and muting the ♭3.

When to use it

G diminished major 7th works as a passing chord in G minor, often moving to G minor or G major 7th. The leading tone F♯ pulls to G, so use it before a G major cadence. It suits dark jazz and film-score tension.

Changing to and from G diminished major 7th

  • Sliding the shape down one fret to the 2nd fret gives F♯ diminished major 7th.

Which voicing to use

The 3rd fret shape keeps the bass on G and is the default. The 5th fret shape repeats the voicing an octave higher, while the 10th fret adds a brighter register for solos.

Other G chords

Common questions

How is G diminished major 7th written?

G diminished major 7th is written G°M7 or GdimM7.

What is the difference between G diminished major 7th and G minor 7th flat 5th?

G diminished major 7th has a major 7th, F♯. G minor 7th flat 5th lowers that note to F, creating a dominant-quality chord.

Why does G diminished major 7th sound so tense?

The diminished 5th between G and D♭ creates a tritone, and the major 7th F♯ rubs against the root. Together they produce a strong leading-tone pull.