A-sharp diminished chord (A#dim)
The A♯ diminished chord (A♯dim) is a diminished triad: A♯, C♯ and E, two minor thirds stacked on top of each other (root, minor third and diminished fifth).
It is the vii° in B major and the vii° in B minor; it sits inside F♯ dominant seventh and tends to resolve to B major, a half step up.
Below: voicings, notes on the fretboard, ukulele, piano, inversions and progressions.
How to play A♯ diminished on guitar
There are 2 guitar voicings.
Frets from the 6th string to the 1st: x = not played, 0 = open string.
- Voicing 1: x-1-2-3-2-x, with A♯ in the bass (fingers x-1-2-4-3-x).
- Voicing 2: 6-7-8-6-x-x, barre at fret 6, with A♯ in the bass (fingers 1-2-4-1-x-x).
Notes of the A♯ diminished chord on the fretboard
A♯ diminished has 3 notes: A♯, C♯ and E. This is where they fall on each string, from the nut to the 12th fret (fret number in parentheses):
- String 6 (E): E (0) · A♯ (6) · C♯ (9) · E (12)
- String 5 (A): A♯ (1) · C♯ (4) · E (7)
- String 4 (D): E (2) · A♯ (8) · C♯ (11)
- String 3 (G): A♯ (3) · C♯ (6) · E (9)
- String 2 (B): C♯ (2) · E (5) · A♯ (11)
- String 1 (E): E (0) · A♯ (6) · C♯ (9) · E (12)
Formula and intervals of A♯ diminished
Its formula is 1-♭3-♭5; in semitones from the root, 0-3-6.
- A♯: Root, the note that gives the chord its name
- C♯: Minor third (m3), 3 semitones above A♯
- E: Diminished fifth (d5), 6 semitones above A♯
A♯ diminished on ukulele
- Ukulele (G C E A): 3-1-0-1; it sounds A♯, C♯, E and A♯.
A♯ diminished on piano
- Keys: A♯4, C♯5 and E5.
Inversions of A♯ diminished
Each inversion puts a different note in the bass.
- Root position: A♯, C♯ and E, with A♯ in the bass.
- First inversion (A♯dim/C♯): C♯, E and A♯, with C♯ in the bass.
- Second inversion (A♯dim/E): E, A♯ and C♯, with E in the bass.
Keys that use A♯ diminished
A♯ diminished appears in 3 major and minor keys.
| Key | Degree | Function |
|---|---|---|
| B major (5 sharps) | vii° | Leading tone |
| G♯ minor (5 sharps) | ii° | Supertonic |
| B minor (harmonic minor, 2 sharps) | vii° | Leading tone |
Progressions with A♯ diminished
- Passing diminished chord in A major (I–♯i°–ii–V): A – A♯dim – Bm – E
A♯ diminished or B♭ diminished?
A♯ diminished (A♯dim) and B♭ diminished (B♭dim) are the same chord with two names: they sound the same and use the same frets.
The spelling depends on the key: it is written B♭ diminished in flat keys and A♯ diminished in sharp keys.
Frequently asked questions
What notes are in the A♯ diminished chord?
A♯, C♯ and E: root, minor third and diminished fifth. Its formula is 1-♭3-♭5.
Which keys use A♯ diminished?
Mainly as the vii° in B major and the vii° in B minor. In total it appears in 3 major and minor keys.
Is B♭ diminished the same chord as A♯ diminished?
Yes: B♭ diminished and A♯ diminished sound the same and are played the same way. It is written B♭ diminished in flat keys and A♯ diminished in sharp keys.
Is A♯ diminished the same as a diminished seventh chord?
No: A♯ diminished is a triad with three notes (A♯, C♯ and E). A diminished seventh chord adds a fourth note, another minor third on top.