The minor seventh flat five chord—often written ø or m7♭5, and called half-diminished—sits halfway between a minor seventh and a fully diminished seventh. It keeps the tense, lean color of the diminished triad, but the added minor seventh stops the harmony from spinning with the same symmetry as a dim7. In jazz and modern pop harmony it is the chord people mean when they say “two chord in minor” in its richest form: iiø7.
How it’s built
Stack a minor third, a diminished fifth, and a minor seventh above the root. Compared with a plain minor triad, the fifth is lowered; compared with a diminished seventh chord, the seventh is a minor seventh, not a diminished seventh—so each inversion does not repeat the same symmetrical pattern in the way dim7 does.
In a natural minor or harmonic minor context, this chord appears on scale degree ii: in C minor, that is D–F–A♭–C, notated Dm7♭5 or Dø. In major keys it is the chord on vii when you read the key in a melodic-harmonic minor way—think Bø in C major leading toward C.
Usage
In jazz, iiø7 most often leads to a dominant chord—classically iiø7 → V7 in minor (e.g. Dm7♭5 → G7 → Cm), or in major as part of a ii–V–I minor inflection. It also appears in turnarounds and as a color chord in modal or linear writing where you want instability without the full diminished vortex.
In pop and rock, you hear it as a passing or borrowed color when arrangers lean on minor-key harmony or jazz-influenced voice-leading—less common than plain minor or dominant chords, but instantly recognizable when it appears before a strong V or i.
Examples
- Standard repertoire — How High the Moon (iiø–V contexts in minor keys)
- Wayne Shorter — harmonic language on several Blue Note–era tunes using half-diminished colors
- Steely Dan — jazz-pop arrangements that use extended minor-key ii chords
- Many Broadway and film scores in minor keys where iiø supports a melancholic lift into the dominant
Play
The half-diminished sound is at its best when resolution is clear—let the ear feel where the tritone wants to go. Practice moving iiø7 into V7 with minimal motion: keep common tones, and resolve the most tense tones by step so the progression sounds inevitable instead of “spiky.”
