C♯dim chord on piano
C♯dim (C sharp diminished) is a diminished chord built on C♯. It has 3 notes, C♯, E and G, and its formula is 1 ♭3 ♭5.
Notes and intervals of C♯dim
From the root upwards, C♯dim contains root (C♯), minor 3rd (E) and diminished 5th (G). Those intervals give the chord its colour: the formula 1 ♭3 ♭5 works the same way in every key, so once you know it for C♯ you can build the chord on any note.
| Degree | Interval | Note |
|---|---|---|
| 1 | root | C♯ |
| ♭3 | minor 3rd | E |
| ♭5 | diminished 5th | G |
How to play C♯dim on piano
Find C♯ and play C♯, E and G together. With the right hand, a common fingering is 1-3-5. With the left hand, reverse it (5-3-1). Keep your wrist level and let the fingers curve, so all 3 keys go down at the same time.
Inversions of C♯dim
An inversion keeps the same notes but puts another one in the bass. C♯dim has 2 inversions besides root position: 1st inversion (E G C♯) and 2nd inversion (G C♯ E). Inversions let you move between chords with tiny hand movements, which is how pianists make progressions sound smooth.
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
To improvise over C♯dim, start with C sharp blues scale. All of these scales contain every note of the chord: C sharp blues scale and C sharp Locrian mode. Aim for the chord notes on strong beats and use the other notes to move between them.
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.
Root position 1 ♭3 ♭5 sits under fingers 1 3 5. Because it is so unstable, voice-lead it: keep each note within a semitone or a tone of where the next chord's notes are. In classical harmony vii° is often played in first inversion (third in the bass), with that bass note doubled rather than the root.
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 piano?
Play C♯, E and G together with the right-hand fingering 1-3-5. You can also play it in 2 inversions, shown on this page.
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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