B♭m7♭5 chord on piano
The B♭m7♭5 chord, or B flat half-diminished, stacks 4 notes on B♭: B♭, D♭, F♭ and A♭. Musicians write its formula 1 ♭3 ♭5 ♭7.
Notes and intervals of B♭m7♭5
Each note of B♭m7♭5 has a job. Counted from the root, you get root (B♭), minor 3rd (D♭), diminished 5th (F♭) and minor 7th (A♭). Change one of these intervals and you get a different chord, which is why the formula 1 ♭3 ♭5 ♭7 is worth memorising rather than the shape alone.
| Degree | Interval | Note |
|---|---|---|
| 1 | root | B♭ |
| ♭3 | minor 3rd | D♭ |
| ♭5 | diminished 5th | F♭ |
| ♭7 | minor 7th | A♭ |
How to play B♭m7♭5 on piano
Put your right-hand thumb on B♭, then add the other notes: B♭, D♭, F♭ and A♭. Teachers usually suggest the fingering 1-2-3-5 (left hand: 5-3-2-1). Press the keys together, release, and repeat until the chord sounds even.
Inversions of B♭m7♭5
An inversion keeps the same notes but puts another one in the bass. B♭m7♭5 has 3 inversions besides root position: 1st inversion (D♭ F♭ A♭ B♭), 2nd inversion (F♭ A♭ B♭ D♭) and 3rd inversion (A♭ B♭ D♭ F♭). Inversions let you move between chords with tiny hand movements, which is how pianists make progressions sound smooth.
Which keys use B♭m7♭5?
You find B♭m7♭5 as a diatonic chord in B major (viiø7). The most common case is B major, where it plays the role of viiø7.
Scales to play over B♭m7♭5
These scales share every note of B♭m7♭5: B flat blues scale and B flat Locrian mode. B flat blues scale is the safest choice; the others add more colour.
About half-diminished chords
A diminished triad plus a minor seventh: 1 ♭3 ♭5 ♭7. Called half-diminished (ø), it is dark and unsettled but softer than a full diminished seventh, because its seventh is minor. It sounds like a question, a sigh that wants to move on. For example Bm7♭5: B D F A.
Its main home is the minor ii-V-i: iiø7 V7 i (for example Bm7♭5 E7 Am). In a major key it sits on viiø7. Jazz, bossa nova and neo-soul use it constantly, and it can also stand in for ivm6 in a minor key, since both chords share the same notes (for example Bm7♭5 and Dm6).
Root position 1 ♭3 ♭5 ♭7 works; jazz pianists usually play the root and ♭7 in the left hand and ♭3 and ♭5 in the right, sometimes adding the 11. In a minor ii-V-i, voice-lead: the ♭3 of iiø7 stays as the ♭7 of V7, and the ♭7 of iiø7 moves down a semitone to the 3 of V7.
m7♭5 is not dim7: dim7 has a diminished seventh (A♭ in Bdim7), m7♭5 a minor seventh (A in Bm7♭5). It is not m6 either, although the two share notes: the bass decides. And remember that m7♭5, m7(♭5), -7♭5 and ø7 are all names for the same chord.
Frequently asked questions
What notes are in the B♭m7♭5 chord?
B♭m7♭5 (B flat half-diminished) contains B♭, D♭, F♭ and A♭. In intervals: root (B♭), minor 3rd (D♭), diminished 5th (F♭) and minor 7th (A♭).
How do you play B♭m7♭5 on piano?
Play B♭, D♭, F♭ and A♭ together with the right-hand fingering 1-2-3-5. You can also play it in 3 inversions, shown on this page.
What scale goes with B♭m7♭5?
B flat blues scale fits B♭m7♭5 best. Other scales that contain all its notes: B flat Locrian mode.
What key is B♭m7♭5 in?
B♭m7♭5 belongs to B major (viiø7). In B major it is the viiø7 chord.
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