Sevenths
A♯ diminished 7th chord
Symmetrical and very tense — every note is a minor 3rd apart.
A♯dim7 is the vii°7 chord in B minor.
- Notes
- A♯C♯EG
- Formula
- 1♭3♭5𝄫7
- Built from
- root · minor 3rd · diminished 5th · diminished 7th
How to play A♯dim7
About the A♯ diminished 7th chord
Playing it
On guitar, A♯dim7 has an open-position shape, x12020, using three fingers alongside the open strings. Don’t strum the low E string.
On piano, A♯dim7 has two black keys (A♯ and C♯) and two white keys.
On ukulele the usual A♯dim7 shape is 0101, using two fingers.
Related chords
Take away the root and the other three notes form C♯dim (C♯ E G) — so you can think of A♯dim7 as C♯dim with A♯ added underneath.
A♯dim7 is symmetrical — its notes are evenly spaced — so C♯dim7, Edim7 and Gdim7 contain exactly the same notes. There are only three different-sounding diminished 7th chords in all.
Move a single note and A♯dim7 becomes a different chord: drop the G for A♯dim, raise E to E♯ for A♯m6 and raise G to G♯ for A♯m7♭5.
