The B♭ Diminished chord is a three-note chord made up of B♭, D♭, and F♭. It is built from a root, minor third, and diminished fifth.
Construction
B♭ Diminished = Root + Minor 3rd + Diminished 5th = B♭ · D♭ · F♭
| Note | Interval | Degree |
|---|---|---|
| B♭ | Root | 1 |
| D♭ | Minor 3rd | ♭3 |
| F♭ | Diminished 5th | ♭5 |
B♭ Diminished Inversions
| Position | Notes |
|---|---|
| Root Position | B♭ – D♭ – F♭ |
| 1st Inversion | D♭ – F♭ – B♭ |
| 2nd Inversion | F♭ – B♭ – D♭ |
Key Signature
A Diminished chord is built from symmetrical or ambiguous intervals, so it doesn’t belong to a single key and has no key signature of its own.
How B♭ Diminished functions in a key
The same chord takes on a different harmonic role depending on the key it appears in. Here is where B♭ Diminished sits diatonically across the common keys:
- In C♭ major, B♭ Diminished is the vii° chord — the dominant.
- In A♭ minor, B♭ Diminished is the ii° chord — a predominant.
B♭ Diminished — Frequently Asked Questions
What is the B♭ Diminished chord on piano?
The B♭ Diminished chord contains the notes B♭ – D♭ – F♭. On piano, play these notes together to sound the chord.
What notes are in the Bb Diminished chord?
The Bb Diminished chord contains: Bb (root), Db (minor third), and Fb (diminished fifth). Both intervals are compressed: the minor third is 3 semitones above the root, and the diminished fifth is 6 semitones — a tritone.
How does Bb Diminished differ from Bb Minor?
Bb Minor has a perfect fifth. Bb Diminished lowers the fifth by one semitone to Fb (diminished fifth). That extra compression creates intense harmonic tension — the tritone between root and diminished fifth is the most dissonant interval in Western music.
What is the symbol for the Bb Diminished?
Bb Diminished is written as Bbdim or Bb°. The ° or "dim" symbol means both the third and fifth are minor/diminished. Do not confuse with Bbdim7 or Bbø (half-diminished), which include additional notes.
What are the inversions of Bb Diminished?
First inversion (Bb Diminished/Db): Db–Fb–Bb. Second inversion (Bb Diminished/Fb): Fb–Bb–Db. Diminished triads are used in classical music as the vii° chord — the chord one semitone below the tonic, with strong resolution pull.
How is Bb Diminished used in music?
Bb Diminished most commonly functions as the vii° chord in a major key, creating strong resolution back to the tonic. It also works as a chromatic passing chord between two nearby chords, and in classical music as a brief point of dissonance. Jazz uses the full four-note dim7 more often than the triad.
What songs use diminished chords?
Michelle (Beatles) uses a diminished chord as a chromatic passing chord. Many classical pieces use vii°–I cadences. Jazz standards use dim7 chords as chromatic passing and approach chords. Diminished harmony also appears in flamenco and film music for dramatic tension.