Bm7b5

Theory

The half-diminished seventh chord is a diminished triad with a minor seventh added — making it "half" diminished compared to the fully diminished seventh chord (which uses a diminished seventh). Bm7b5 uses B, D, F, A. The diminished fifth (F) creates the characteristic darkness, while the minor seventh (A) — a whole step above the diminished fifth — distinguishes it from the fully diminished chord. In jazz, this chord is the ii chord in minor key ii–V–i progressions. The symbol ø7 (ø = diminished triad + minor seventh) is common in jazz notation. It has a dark, sophisticated quality that is essential in modal jazz, minor key ballads, and neo-soul harmony.

Intervals & Formula

Formula: 1 – ♭3 – ♭5 – ♭7

Musical Meaning

The half-diminished chord (also written m7♭5) combines minor darkness with an unstable flat fifth and a minor seventh. It's a cornerstone of jazz harmony, appearing as the ii chord in minor key ii–V–i progressions and lending music a sophisticated, unresolved tension.

Sounds Like This

🌑 Other dark sounds to explore

Voicing Tips

Voice the half-diminished seventh with third–flat fifth–flat seventh in the right hand over the root in the left. The flat fifth is the chord's most distinctive note — it creates the dark, unresolved quality. In minor ii–V–i, this chord strongly wants to move to the V7 (especially V7♭9) and then to the minor tonic.

Practical Uses

• iiø7 chord in the minor ii–V–i jazz cadence (essential in minor key jazz)
• vii7 chord in major key progressions for a dark passing color
• Sophisticated harmonic color in neo-soul and modern jazz writing
• Building tension before resolving to a minor tonic

Common Progressions

Related Chords