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C♯ diminished 7th chord on ukulele (C♯dim7)
Also called or written C♯dim7 or C♯°7
C♯ diminished 7th is built from C♯, E, G, B♭. The 6th fret shape sits high enough to require clean finger placement on every string.
How it is built
Formula 1, ♭3, ♭5, ♭♭7
How do you play a C♯ diminished 7th chord on ukulele?
C♯ diminished 7th is played at the 6th fret as 6 7 6 7: index finger on the G string at fret 6, ring finger on the C string at fret 7, middle finger on the E string at fret 6 and pinky finger on the A string at fret 7.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 6 | 1 | C♯ (1) |
| 3 (C) | 7 | 3 | G (♭5) |
| 2 (E) | 6 | 2 | B♭ (6) |
| 1 (A) | 7 | 4 | E (♭3) |
AdvancedThe pinky must reach fret 7 on the A string while the ring finger holds fret 7 on the C string, creating a wide stretch.
C♯dim7/B♭ inversion
C♯ diminished 7th is played at the 9th fret as 9 10 9 10: index finger on the G string at fret 9, ring finger on the C string at fret 10, middle finger on the E string at fret 9 and pinky finger on the A string at fret 10.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 9 | 1 | E (♭3) |
| 3 (C) | 10 | 3 | B♭ (6) |
| 2 (E) | 9 | 2 | C♯ (1) |
| 1 (A) | 10 | 4 | G (♭5) |
Open
C♯ diminished 7th is played in open position as 0 1 0 1: index finger on the C string at fret 1 and middle finger on the A string at fret 1. The G and E strings ring open.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | open | — | G (♭5) |
| 3 (C) | 1 | 1 | C♯ (1) |
| 2 (E) | open | — | E (♭3) |
| 1 (A) | 1 | 2 | B♭ (6) |
C♯dim7/E inversion
C♯ diminished 7th is played at the 3rd fret as 3 4 3 4: index finger on the G string at fret 3, ring finger on the C string at fret 4, middle finger on the E string at fret 3 and pinky finger on the A string at fret 4.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 3 | 1 | B♭ (6) |
| 3 (C) | 4 | 3 | E (♭3) |
| 2 (E) | 3 | 2 | G (♭5) |
| 1 (A) | 4 | 4 | C♯ (1) |
Why it sounds like that
C♯ diminished 7th stacks minor thirds: 1, ♭3, ♭5, ♭♭7. The ♭♭7, B♭, is the same pitch as A but spelled as a diminished seventh to keep the chord's symmetry. Compare it with C♯ minor 7th flat 5th, which has a minor seventh instead.
What goes wrong with C♯ diminished 7th?
- Letting the index finger collapse and mute the C string.
- Pressing the pinky on the A string fret 7 without enough arch, deadening the E string.
- Strumming before all four fingers are firmly placed.
When to use it
C♯ diminished 7th works as a passing chord between C♯ minor 7th flat 5th and E♭ minor. Its tense, symmetrical sound suits jazz turnarounds and dramatic pauses in ballads.
Changing to and from C♯ diminished 7th
- Sliding the shape down one fret to the 5th fret gives C diminished 7th.
- Sliding the shape up one fret to the 7th fret gives D diminished 7th.
Which voicing to use
The 6th fret voicing puts C♯ in the bass, giving the most direct root-position sound. The C♯dim7/E inversion at the 9th fret places E in the bass, which softens the chord's attack and works well when moving to an E♭ chord.
Other C♯ chords
Common questions
How is C♯ diminished 7th written?
C♯ diminished 7th is written C♯°7 or C♯dim7. The root is C♯, also written C#. It is also spelled D♭ in enharmonic notation for the same sounding root.
Why does C♯ diminished 7th use B♭ instead of A?
The diminished seventh interval from C♯ is B♭, not A. Spelling it B♭ keeps the chord's formula as 1, ♭3, ♭5, ♭♭7. Using A would make the interval a major sixth.
How does C♯ diminished 7th differ from C♯ minor 7th flat 5th?
C♯ minor 7th flat 5th has a minor seventh, B, while C♯ diminished 7th has a diminished seventh, B♭. That one-semitone difference makes the diminished chord sound more tense and symmetrical.
Can I play C♯ diminished 7th with a barre?
No, the 6th fret voicing uses four separate fingers. A barre would fret the G and E strings at fret 6, but you still need fingers for the C and A strings at fret 7.