Bbdim Guitar Chord
Bb Diminished · also written A#dim · Bb–Db–Fb
Bbdim is the Bb diminished chord: Bb–Db–Fb. Its sound is tense and unstable — stacked minor 3rds that work as dramatic passing chords. It's also written as A#dim — same notes, same shapes, different spelling.
You'll rarely sit on Bbdim for a full bar — diminished chords are connectors. Classic uses: passing between the I and ii chords in A major, or substituting for the V7♭9 a half-step below. The symmetrical shape repeats every three frets, so one grip gives you four chords.
The most common way to play Bbdim is the symmetric shell at the 1st fret (x 1 2 3 2 x, low E string to high E string). Below you'll find 7 ways to play it across the neck, from open position to barre and shell voicings, with the theory behind the chord and the progressions it lives in.
How to Play Bbdim: 7 Voicings
Frets are listed from the low E string to the high E string. x = don't play that string, 0 = open string.
Bbdim Chord Theory
| Interval | R | ♭3 | ♭5 |
|---|---|---|---|
| Note | Bb | Db | Fb |
Bbdim is built from the Bb minor scale.
Bbdim Chord FAQ
What notes are in the Bbdim chord?
Bbdim contains 3 notes: Bb (R), Db (♭3), Fb (♭5). The interval formula for a diminished chord is R–♭3–♭5.
What is the easiest way to play Bbdim on guitar?
Use the symmetric shell at the 1st fret: x 1 2 3 2 x (frets listed from the low E string to the high E string, x = don't play that string). Bbdim has no open-position shape in standard tuning, so this movable form is the standard starting point.
Is Bbdim a major or minor chord?
Bbdim is built on a minor triad (Bb–Db–Fb) with the ♭5 added, so it behaves as a minor-family chord.
Is Bbdim the same as A#dim?
Yes. Bb and A# are enharmonic equivalents — the same pitch written two ways. Bbdim and A#dim use identical shapes and frets; which spelling you see depends on the key of the song.
What keys use the Bbdim chord?
Bbdim appears diatonically in Db major (as vi), Ab major (as ii), and F# major (as iii) — plus it's the home chord (i) of Bb minor.
Related Chords
Hear yourself play Bbdim
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