C♯dim chord on guitar
The C♯dim chord, or C sharp diminished, stacks 3 notes on C♯: C♯, E and G. Musicians write its formula 1 ♭3 ♭5.
Notes and intervals of C♯dim
Each note of C♯dim has a job. Counted from the root, you get root (C♯), minor 3rd (E) and diminished 5th (G). Change one of these intervals and you get a different chord, which is why the formula 1 ♭3 ♭5 is worth memorising rather than the shape alone.
| Degree | Interval | Note |
|---|---|---|
| 1 | root | C♯ |
| ♭3 | minor 3rd | E |
| ♭5 | diminished 5th | G |
How to play C♯dim on guitar
Start with the first diagram: x 4 2 x 2 3, read from the 6th string (low E) to the 1st string (high E). Your lowest note is C♯. The next positions give the same notes in a different order, which is useful when you want C♯dim to sit closer to the surrounding chords.
This is a barre or movable shape: keep your index finger straight and close to the fret, and press with the side of the finger rather than the flat pad.
Which keys use C♯dim?
You find C♯dim as a diatonic chord in D major (vii°). The most common case is D major, where it plays the role of vii°.
Scales to play over C♯dim
These scales share every note of C♯dim: C sharp blues scale and C sharp Locrian mode. C sharp blues scale is the safest choice; the others add more colour.
About diminished chords
Two stacked minor thirds: 1 ♭3 ♭5. The diminished fifth (a tritone) makes the diminished chord the most unstable triad: tense, dark and restless. It rarely stands alone and pulls towards the chord a semitone above its root. For example Bdim: B D F. Add a diminished seventh and you get the symmetrical diminished seventh chord.
In a major key it sits on vii° (for example Bdim in C major), acting as a lighter V7 that resolves to I. In a minor key it sits on ii°. Passing diminished chords connect neighbouring chords chromatically, for example I ♯i° ii (C C♯dim Dm). Classical music, jazz, ragtime and film scores use it to build suspense.
The triad is usually played as a small three or four-string shape on the middle or top strings, since full barres are awkward. Many guitarists play dim7 instead: a movable four-string shape that repeats every 3 frets, because the chord divides the octave into equal minor thirds. Slide it up three frets to hear a new inversion.
dim (three notes) and dim7 (four notes, with a diminished seventh) are not the same, though 'dim' on a jazz chart often means dim7. And dim is not m7♭5: the half-diminished chord adds a minor seventh (for example Bm7♭5: B D F A) and sounds much softer. Symbols: ° means diminished, ø means half-diminished.
Frequently asked questions
What notes are in the C♯dim chord?
C♯dim (C sharp diminished) contains C♯, E and G. In intervals: root (C♯), minor 3rd (E) and diminished 5th (G).
How do you play C♯dim on guitar?
The easiest shape is x 4 2 x 2 3, from the low E string to the high E string. This page shows 3 positions with finger numbers.
What scale goes with C♯dim?
C sharp blues scale fits C♯dim best. Other scales that contain all its notes: C sharp Locrian mode.
What key is C♯dim in?
C♯dim belongs to D major (vii°). In D major it is the vii° chord.
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