Play ChordRunner

Learn › C Diminished Chord on Guitar (Cdim)

New Released in April 2026

C Diminished Chord on Guitar (Cdim)

C diminished (Cdim) on the guitar: press the strings shown below; some strings ring open. Strum from the 5th string down and you hear C, Eb, Gb. Here is the shape, finger by finger, plus the chords you will play next to it.

Play the demo

No account, no download. The demo has limited content. Advanced features are in ChordRunner Premium.

  • MIDI keyboard
  • Digital or acoustic piano
  • Guitar
  • Computer, phone or tablet
3fr××
Cdim C Eb Gb

The C diminished guitar chord, finger by finger

3fr××
Cdim C Eb Gb

Finger by finger

  • Index: 5th string (A), fret 3
  • Middle: 4th string (D), fret 4
  • Little: 3rd string (G), fret 5
  • Ring: 2nd string (B), fret 4

Which strings to strum

x3454x: × = do not play, 0 = open string.

Cdim and its neighbours

These chords share notes with Cdim and sound right next to it. Practise switching between them.

C · F · G

Which note each string plays

5th string (A)fret 3: C
4th string (D)fret 4: Gb
3rd string (G)fret 5: C
2nd string (B)fret 4: Eb

Slide this shape along the neck: fret 1 = Bbdim, fret 2 = Bdim, fret 4 = C#dim, fret 5 = Ddim.

Practise Cdim in three steps

  1. Place the fingers one at a time, then strum and listen to each string.
  2. Take the hand off and put the whole shape back at once, ten times in a row.
  3. Change from Cdim to C and back for a minute; then add F.

Where Cdim is used

Cdim wants to move up one fret: play Cdim, then C# or C#m, and it resolves.

ChordRunner on a phone next to an acoustic guitar, with a chord block on screen

Play Cdim in a game

Cdim turns up between other chords in ChordRunner; strum it on time and the runner jumps. MIDI keyboard or microphone, both work. MIDI keyboard or microphone, both work.

Play the demo

Cdim on piano · Easy guitar chords · Guitar chord game

Common questions

Is Cdim easy on guitar?

Yes, it is one of the open chords beginners learn first. Start slowly, check that every string rings, then practise switching to C.

Which fingers do I use for Cdim?

Index finger: 5th string (A), fret 3, middle finger: 4th string (D), fret 4, little finger: 3rd string (G), fret 5, ring finger: 2nd string (B), fret 4.

Can I practise Cdim with a microphone or MIDI keyboard?

Both work in ChordRunner. The microphone hears an acoustic or electric guitar; a USB MIDI keyboard is detected automatically. Either way C, Eb, Gb must sound together.

Your instrument is the controller.

ChordRunner is a browser game that teaches piano and guitar chords: a chord appears on screen, you play it on a real instrument, and your runner jumps. MIDI keyboard or microphone, both work.

Try the demo

Keep learning

Easy Guitar Chords for Beginners

Easy guitar chords for beginners: Em, Am, C, G, D, E, A and Dm with diagrams, the order to learn them and how …

Guitar Chord Chart: 21 Essential Chords

Guitar chord chart with diagrams: the 7 major, 7 minor and 7 seventh chords guitarists use most, how to read a…

Guitar Chord Game: Practise Chords on Your Guitar

A guitar chord game in your browser: a chord appears, you strum it, the microphone hears it. Practise chord ch…

C Diminished Chord on Piano (Cdim)

C diminished chord on piano (Cdim): notes C Eb Gb, keyboard, inversions, fingering and where it resolves.…

Chord Training That Feels Like a Game

Interactive chord training in your browser. Play major, minor, 7th and extended chords on a MIDI keyboard or a…

Master All 12 Major Chords on Piano

Every major chord on piano with notes and fingering, plus an interactive game that drills all 12 until they ar…