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A diminished 7th chord on guitar (Adim7)
Also called or written Adim7 or A°7
A diminished 7th contains A, C, E♭ and G♭. The open shape is a stretchy four-finger grip that suits advanced players.
How it is built
Formula 1, ♭3, ♭5, ♭♭7
- Root positionA–C–E♭–G♭Adim7×-0-1-2-1-2
- First inversionC–E♭–G♭–AAdim7/C×-3-1-2-1-2
- Second inversionE♭–G♭–A–CAdim7/E♭×-×-1-2-1-2
- Third inversionG♭–A–C–E♭Adim7/G♭2-0-1-2-1-×
How do you play an A diminished 7th chord on guitar?
A diminished 7th is played in open position as × 0 1 2 1 2: index finger on the D string at fret 1, ring finger on the G string at fret 2, middle finger on the B string at fret 1 and pinky finger on the high e string at fret 2. The A string rings open. The low E string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | muted | — | — |
| 5 (A) | open | — | A (1) |
| 4 (D) | 1 | 1 | E♭ (♭5) |
| 3 (G) | 2 | 3 | A (1) |
| 2 (B) | 1 | 2 | C (♭3) |
| 1 (e) | 2 | 4 | G♭ (6) |
AdvancedThe open shape requires stretching the pinky to the 2nd fret of the high E while the index and middle fingers hold the 1st fret on adjacent strings.
4th fret
A diminished 7th is played at the 4th fret as 5 6 4 5 4 ×: barre your index finger across fret 4, middle finger on the low E string at fret 5, pinky finger on the A string at fret 6 and ring finger on the G string at fret 5. The high e string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 5 | 2 | A (1) |
| 5 (A) | 6 | 4 | E♭ (♭5) |
| 4 (D) | 4 | 1 (barre) | G♭ (6) |
| 3 (G) | 5 | 3 | C (♭3) |
| 2 (B) | 4 | 1 (barre) | E♭ (♭5) |
| 1 (e) | muted | — | — |
5th fret
A diminished 7th is played at the 5th fret as 5 6 7 5 7 5: barre your index finger across fret 5, middle finger on the A string at fret 6, ring finger on the D string at fret 7 and pinky finger on the B string at fret 7.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 5 | 1 (barre) | A (1) |
| 5 (A) | 6 | 2 | E♭ (♭5) |
| 4 (D) | 7 | 3 | A (1) |
| 3 (G) | 5 | 1 (barre) | C (♭3) |
| 2 (B) | 7 | 4 | G♭ (6) |
| 1 (e) | 5 | 1 (barre) | A (1) |
7th fret
A diminished 7th is played at the 7th fret as × × 7 8 7 8: index finger on the D string at fret 7, ring finger on the G string at fret 8, middle finger on the B string at fret 7 and pinky finger on the high e string at fret 8. The low E and A strings stay muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | muted | — | — |
| 5 (A) | muted | — | — |
| 4 (D) | 7 | 1 | A (1) |
| 3 (G) | 8 | 3 | E♭ (♭5) |
| 2 (B) | 7 | 2 | G♭ (6) |
| 1 (e) | 8 | 4 | C (♭3) |
10th fret
A diminished 7th is played at the 10th fret as × 12 10 11 10 11: barre your index finger across fret 10, pinky finger on the A string at fret 12, middle finger on the G string at fret 11 and ring finger on the high e string at fret 11. The low E string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | muted | — | — |
| 5 (A) | 12 | 4 | A (1) |
| 4 (D) | 10 | 1 (barre) | C (♭3) |
| 3 (G) | 11 | 2 | G♭ (6) |
| 2 (B) | 10 | 1 (barre) | A (1) |
| 1 (e) | 11 | 3 | E♭ (♭5) |
Why it sounds like that
A diminished 7th is built from the intervals 1, ♭3, ♭5 and ♭♭7. The ♭♭7, a diminished seventh above the root, gives the chord its tense, symmetrical quality. Compare it with A minor 7th flat 5th, which has a minor seventh instead.
What goes wrong with A diminished 7th?
- Letting the low E string ring instead of muting it.
- Flattening the ring finger onto the B string, which deadens the 1st fret note.
- Arching the pinky too low so it touches the B string and mutes the 2nd fret.
When to use it
A diminished 7th works as a passing chord between A minor 7th flat 5th and B minor. It suits tense jazz and classical passages.
Changing to and from A diminished 7th
- Sliding the shape down two frets to the 2nd fret gives G diminished 7th.
- From B major, lift the ring and pinky fingers and move the index and middle fingers down one string each.
Which voicing to use
The open position keeps the root A in the bass and is easiest to grab. The 5th fret barre voicing puts the root on the low E string for a darker sound.
Other A chords
Common questions
How is A diminished 7th written?
A diminished 7th is written A°7 or Adim7.
What is the difference between A diminished 7th and A minor 7th flat 5th?
A diminished 7th has a diminished seventh (G♭), while A minor 7th flat 5th has a minor seventh (G). The diminished seventh makes the chord fully diminished and more tense.
Why is the low E string muted in the open shape?
The open low E is not a chord tone of A diminished 7th. Muting it keeps the voicing clean and the bass note on A.