The B-flat diminished seventh chord (B♭°7) is a four-note chord consisting of the notes B♭, D♭, F♭, and A𝄫. It is built by stacking three minor thirds on top of the root, resulting in a chord with a highly tense and unstable quality. This chord is frequently used in classical, jazz, and contemporary music to create dramatic tension, suspense, or a sense of inevitable resolution. The B-flat diminished seventh chord often functions as a leading-tone chord, guiding the harmony smoothly to a more stable chord, and its symmetrical structure allows it to be transposed easily, providing composers and performers with a versatile tool for expressive and dynamic harmonic progressions.
Name: B-flat diminished seventh chord
Symnonyms:: B-flat fully diminished chord
Notes: B♭, D♭, F♭, A𝄫
Intervals: 1, ♭3, ♭5, 𝄫7
Chord symbol: B♭o7
Alternative symbols: B♭dim7, B♭dim, B♭o
Type: Tetrad (four-note chord)
B-flat diminished seventh chord on the Staff
B-flat diminished seventh chord on Piano
B-flat diminished seventh chord on Guitar
B-flat diminished seventh chord on Ukulele
Rowan Ellis is a musician and educator with a passion for exploring the language of harmony and melody. With years of experience across classical, jazz, and contemporary styles, Rowan breaks down music theory into clear, practical insights. His goal is to make chords and scales less intimidating and more inspiring for every musician.