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A Diminished Chord

Adim stacks two minor thirds: A to C, then C to E flat. Its lowered fifth creates a tritone above the root and gives the triad a strong need to move.

  • Notes: A-C-E flat
  • Symbol: Adim
  • viidim in Bb major
  • Lowered fifth
Switch chordAdim

How to play an A diminished chord

Notes: A - C - Eb · symbol Adim

  • Root position

    A - C - Eb
    C4C5
    Right hand 1-3-5 · Left 5-3-1

  • 1st inversion

    C - Eb - A
    C4C5
    Right hand 1-2-5 · Left 5-3-1

  • 2nd inversion

    Eb - A - C
    C4C5
    Right hand 1-3-5 · Left 5-2-1

Where does A diminished belong?

In Bb major, this diminished triad can act as a leading-tone chord that approaches the tonic.
Play the role cards to hear how its surrounding chords change the job it does; Diatonic Chords explains the basic numbered roles.

  • In Bb majorLeading-tone chord
    vii°

    A is the leading tone of Bb, so the chord leans hard toward it.

    BbIEbIVAdimvii°BbI
  • In G minorThe ii° in minor
    ii°

    The minor-key version of ii-V-i, heading to Gm.

    Adimii°DVGmi
  • In Bb minorMinor-key pull
    vii°

    From harmonic minor: the same chord pulls just as hard toward Bbm.

    BbmiEbmivAdimvii°Bbmi

Progressions to try

  • BbEbAdimBb

    Adim is a leading-tone triad that resolves by step into the final major tonic.

  • AdimDGm

    In G minor, Adim serves as ii diminished before the dominant and minor tonic.

  • BbmEbmAdimBbm

    The leading-tone sound also works before a minor tonic; check the chord's spelling in this key.

Which shape should you use?

On guitar, start with the open x0121x grip. Let the open strings ring and keep any strings marked x silent.

On ukulele, start with 5353, played at the 3rd fret. The 8986 grip moves the chord to another register.

On piano, play A-C-E flat. Move A up an octave to reach the first inversion, C-E flat-A; the notes remain the same while the lowest voice changes.

What are the inversions?

A is the root, C the minor third and E flat the diminished fifth, six semitones above the root.

  • Root position: A-C-E flat, with A lowest.
  • First inversion: C-E flat-A, written Adim/C if C is lowest in the whole arrangement.
  • Second inversion: E flat-A-C, written Adim/Eb if E flat is lowest in the whole arrangement.

A slash chord names the note in the bass, not merely the lowest note under one hand. Chord Inversions shows how to read that distinction.

How does Adim differ from Am?

Keep A and C, then raise the diminished fifth E flat to E. That makes Am. This page is about the three-note diminished triad, not a diminished seventh chord. Try that one-note change on piano, then use the comparer to hear it in the full chord. See Am for the other chord's full spelling and roles.

  • Adim

    A - C - Eb
    C4

    A diminished

  • Am

    A - C - E
    C4

    A minor

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