B Half-diminished
Bm7b5
Notes
B · D · F · A
Intervals
- RootB (1P)
- Minor 3rdD (3m)
- Diminished 5thF (5d)
- Minor 7thA (7m)
Fretboard
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About
The B half-diminished (B–D–F–A), also written Bø7, is the naturally occurring chord on the seventh degree of a major scale and on the second degree of a natural minor scale. Its primary role in jazz is as the ii chord in a minor ii–V–i: Bm7♭5 → E7 → Am. The F is the defining color tone — without it, the chord collapses to a plain Bm7. The 3rd and ♭7 together establish the minor seventh quality. On guitar, the fifth is essential and should not be omitted, since the ♭5 is precisely what distinguishes this chord. Compared to Bdim7, m7♭5 is more grounded due to the natural (rather than doubly-flatted) seventh, giving it a somber but less frantic character.
Similar chords
Chords sharing two or more notes with this one, ranked by overlap.
Scales containing this chord
- B Blues (deg 1)
- A Diminished (deg 2)
- A Harmonic Minor (II)
- A Natural Minor (II)
- C Diminished (deg 8)
- C Major (VII)
- C Melodic Minor (VII)
- D Melodic Minor (VI)
- F♯ Diminished (deg 4)
- F♯ Harmonic Minor (IV)
- B Locrian (I)
- D Dorian (VI)
- E Phrygian (V)
- F Lydian (IV)
- G Mixolydian (III)
Scales whose notes include every chord tone. Roman numeral marks the chord root’s position in the scale; dashed badges aren’t linked yet.