A# diminished 7th · Piano
A#dim7 Chord on Piano
The A#dim7 chord (A# diminished 7th) is built from the notes A#, C#, E and G. The keyboard diagram below shows exactly which keys to press. The same chord is also written Bbdim7; both spellings sound identical.
Chord diagrams
Notes in this chord
- A♯
- C♯
- E
- G
Degrees: 1 – ♭3 – ♭5 – ♭♭7
Also written: Bbdim7
How to play
To play A#dim7 on piano, press A#, C#, E and G together. In root position the lowest note is A#, and the finger numbers follow the keys left to right in the diagram.
Theory behind the chord
Diminished seventh chords divide the octave into four equal minor thirds. Every inversion sounds the same, so a single shape can be slid up the neck to lead into several different keys. On A#dim7 this structure sits on the root A#, so the degrees 1 – ♭3 – ♭5 – ♭♭7 map onto A#, C#, E and G.
Frequently asked questions
- Which notes are in the A#dim7 chord?
- A#dim7 contains the notes A#, C#, E and G. Relative to the root these are the degrees 1 – ♭3 – ♭5 – ♭♭7.
- Are A#dim7 and Bbdim7 the same chord?
- Yes. A#dim7 and Bbdim7 are enharmonically identical — the spelling differs but the frets and keys are the same. Which name is used depends on the key of the piece.
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