A♭ diminished 7 chordA♭dim7

Built from

• A♭root
• C♭minor 3rd
• Dflat 5th
• Fdiminished 7th

Every note is three frets from the next, so the chord has no centre and can slide anywhere.

Hear it in a progression

• Passing chord

  Slides between two chords, old-time and jazzy. In G major.

  Capo and transpose

  1. GI
  2. A♭dim7♯i°7
  3. Am7ii7
  4. D7V7

• Leading home

  Maximum suspense, then release. In A minor.

  Capo and transpose

  1. Dmiv
  2. A♭dim7vii°7
  3. Ami
  4. Ami

Where it goes next

Thinking in A major, where it is the vii° chord.

• A

  I. Its top note leads up one fret, straight home.

• C♯m

  iii. Settles onto iii.

Sounds close

• Ddim7

  The same four notes, named from another root. Both have A♭, C♭, D and F.

• D♭7

  Shares 3 of its notes. Both have A♭, C♭ and F.

• E7

  Shares 3 of its notes. Both have A♭, C♭ and D.

• G7

  Shares 3 of its notes. Both have C♭, D and F.

Keys it lives in

• F♯ minoras ii°
• A majoras vii°