Triads
B♭ diminished chord
Tense and unstable — it usually wants to resolve up by a half step.
B♭dim is the vii° chord in B major. In minor keys: ii° in G♯ minor.
- Notes
- B♭D♭F♭
- Formula
- 1♭3♭5
- Built from
- root · minor 3rd · diminished 5th
How to play B♭dim
About the B♭ diminished chord
Playing it
On guitar, B♭dim has an open-position shape, x12320, using four fingers alongside the open strings. Don’t strum the low E string.
On piano, B♭dim has two black keys (B♭ and D♭) and one white key.
On ukulele the usual B♭dim shape is 3101, using three fingers.
Related chords
Move a single note and B♭dim becomes a different chord: raise F♭ to F for B♭m, add A♭ for B♭m7♭5 and add A𝄫 for B♭dim7.
Where you’ll hear it
Notice the F♭ in B♭dim (B♭ D♭ F♭): each note of the chord takes its own letter (B–D–F), so the diminished 5th has to be written F♭ rather than E — the same key on a piano, spelled to fit the chord.
