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C♯ diminished 7th chord on guitar (C♯dim7)
Also called or written C♯dim7 or C♯°7
C♯ diminished 7th contains C♯, E, G, and B♭. This advanced chord stacks minor thirds, creating a tense, symmetrical sound.
How it is built
Formula 1, ♭3, ♭5, ♭♭7
- Root positionC♯–E–G–B♭C♯dim7×-4-2-3-2-3
- First inversionE–G–B♭–C♯C♯dim7/E0-1-2-0-2-0
- Second inversionG–B♭–C♯–EC♯dim7/G3-1-2-0-2-0
- Third inversionB♭–C♯–E–GC♯dim7/B♭×-1-2-0-2-0
How do you play a C♯ diminished 7th chord on guitar?
C♯ diminished 7th is played at the 2nd fret as × 4 2 3 2 3: barre your index finger across fret 2, pinky finger on the A string at fret 4, middle finger on the G string at fret 3 and ring finger on the high e string at fret 3. The low E string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | muted | — | — |
| 5 (A) | 4 | 4 | C♯ (1) |
| 4 (D) | 2 | 1 (barre) | E (♭3) |
| 3 (G) | 3 | 2 | B♭ (6) |
| 2 (B) | 2 | 1 (barre) | C♯ (1) |
| 1 (e) | 3 | 3 | G (♭5) |
AdvancedThe index barre must fret the D and B strings cleanly while the pinky reaches the 4th fret on the A string.
3rd fret
C♯ diminished 7th is played at the 3rd fret as × 4 5 3 5 3: barre your index finger across fret 3, middle finger on the A string at fret 4, ring finger on the D string at fret 5 and pinky finger on the B string at fret 5. The low E string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | muted | — | — |
| 5 (A) | 4 | 2 | C♯ (1) |
| 4 (D) | 5 | 3 | G (♭5) |
| 3 (G) | 3 | 1 (barre) | B♭ (6) |
| 2 (B) | 5 | 4 | E (♭3) |
| 1 (e) | 3 | 1 (barre) | G (♭5) |
8th fret
C♯ diminished 7th is played at the 8th fret as 9 10 8 9 8 ×: barre your index finger across fret 8, middle finger on the low E string at fret 9, pinky finger on the A string at fret 10 and ring finger on the G string at fret 9. The high e string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 9 | 2 | C♯ (1) |
| 5 (A) | 10 | 4 | G (♭5) |
| 4 (D) | 8 | 1 (barre) | B♭ (6) |
| 3 (G) | 9 | 3 | E (♭3) |
| 2 (B) | 8 | 1 (barre) | G (♭5) |
| 1 (e) | muted | — | — |
9th fret
C♯ diminished 7th is played at the 9th fret as 9 10 11 9 11 9: barre your index finger across fret 9, middle finger on the A string at fret 10, ring finger on the D string at fret 11 and pinky finger on the B string at fret 11.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 9 | 1 (barre) | C♯ (1) |
| 5 (A) | 10 | 2 | G (♭5) |
| 4 (D) | 11 | 3 | C♯ (1) |
| 3 (G) | 9 | 1 (barre) | E (♭3) |
| 2 (B) | 11 | 4 | B♭ (6) |
| 1 (e) | 9 | 1 (barre) | C♯ (1) |
11th fret
C♯ diminished 7th is played at the 11th fret as × × 11 12 11 12: index finger on the D string at fret 11, ring finger on the G string at fret 12, middle finger on the B string at fret 11 and pinky finger on the high e string at fret 12. 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) | 11 | 1 | C♯ (1) |
| 3 (G) | 12 | 3 | G (♭5) |
| 2 (B) | 11 | 2 | B♭ (6) |
| 1 (e) | 12 | 4 | E (♭3) |
Why it sounds like that
C♯ diminished 7th is built from the formula 1, ♭3, ♭5, ♭♭7. The diminished 5th between C♯ and G gives it its unstable quality. Compare it to C♯ minor 7th flat 5th, which has a minor 7th instead of a diminished 7th.
What goes wrong with C♯ diminished 7th?
- Letting the low E string ring out, which changes the bass note from C♯ to E.
- Pressing too hard with the barre, causing the G string to buzz.
- Allowing the pinky to touch the D string, muting the C♯.
When to use it
C♯ diminished 7th often substitutes for C♯ minor 7th flat 5th in jazz and classical passages. It creates tension that resolves to E minor or E♭ major. Use it in dramatic, suspenseful moments.
Changing to and from C♯ diminished 7th
- Slide the shape down one fret to the 1st fret to play C diminished 7th.
- Move the shape up one fret to the 3rd fret to play D diminished 7th.
Which voicing to use
The 2nd fret voicing keeps C♯ as the lowest note, giving a clear root position. The 11th fret shape omits the low strings, producing a brighter, thinner sound.
Other C♯ chords
Common questions
How is C♯ diminished 7th written?
C♯ diminished 7th is written C♯°7 or C♯dim7. The root is also spelled C# in ASCII. It is also spelled D♭ in enharmonic notation for the same sounding root.
What is the difference between C♯ diminished 7th and C♯ diminished?
C♯ diminished 7th adds a diminished 7th interval (B♭) to the C♯ diminished triad. The triad has only C♯, E, and G.
Why does C♯ diminished 7th sound unstable?
C♯ diminished 7th contains two diminished 5th intervals: C♯–G and E–B♭. These tritones create tension that demands resolution.