B♭ Half-Whole Diminished at a glance
The half-whole diminished is the standard scale over a dominant 7♭9 chord in jazz. Its symmetry means a phrase transposed by minor third still fits the chord, perfect for fast harmonic motion. Built on the root B♭, the scale takes on the specific colour and pitch range of that key - making it especially useful in genres and registers where B♭ is a comfortable tonal centre.
| Notes | B♭ C♭ D♭ D E F G A♭ |
|---|---|
| Formula | 1P · 2m · 3m · 3M · 4A · 5P · 6M · 7m |
| Step pattern | H W H W H W H W |
B♭ Half-Whole Diminished on the piano
Improvisation drone · B♭
Loop the root note as a pad to practice improvising over this scale.
On the piano B♭ Half-Whole Diminished uses three black keys (B♭, D♭ and A♭) and five white. C♭ is the white key you'd normally call B.
B♭ · C♭ · D♭ · D · E · F · G · A♭
Try B♭ Half-Whole Diminished on the virtual piano
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B♭ Half-Whole Diminished on the guitar
B♭ Half-Whole Diminished - fr 0–12
B♭ Half-Whole Diminished on the staff
Notes of the B♭ Half-Whole Diminished scale
| Degree | Note | Interval | Semitones | Hear |
|---|---|---|---|---|
| 1 | B♭ | unison1P | 0 | |
| 2 | C♭ | minor 2nd2m | 1 | |
| 3 | D♭ | minor 3rd3m | 3 | |
| 4 | D | major 3rd3M | 4 | |
| 5 | E | augmented 4th4A | 6 | |
| 6 | F | perfect 5th5P | 7 | |
| 7 | G | major 6th6M | 9 | |
| 8 | A♭ | minor 7th7m | 10 |
What makes B♭ Half-Whole Diminished different
The half-whole diminished scale has eight notes that alternate a half step and a whole step, so its pattern repeats every minor third. That symmetry means there are only three different ones: the scale on C has the same notes as those on E♭, G♭ and A. It holds the 1, 3, 5 and ♭7 of a dominant chord plus the ♭9, ♯9 and ♯11. Its natural fifth and natural 13th are what separate it from the Altered scale over the same chord.
How to use the B♭ Half-Whole Diminished scale
Because B♭ Half-Whole Diminished has fewer or more than seven notes, it doesn't produce a standard set of seven diatonic triads. Instead, build chords by stacking thirds within the scale or use it as a melodic colour over chords drawn from a related diatonic key.
The half-whole diminished is the standard scale over a dominant 7♭9 chord in jazz. Its symmetry means a phrase transposed by minor third still fits the chord, perfect for fast harmonic motion.
Practice tips
Practise the scale starting from each chord tone of the underlying dominant 7♭9 (1, ♭3, ♭5, ♭♭7) — they're all four equivalent because of the symmetry, and that insight is what makes diminished playing fast and fluid.
Formula & step pattern
The B♭ Half-Whole Diminished scale follows an eight-note symmetric scale alternating half-step then whole-step (1, ♭2, ♭3, 3, ♯4, 5, 6, ♭7). Step pattern: H - W - H - W - H - W - H - W. Intervals from the root: 1P · 2m · 3m · 3M · 4A · 5P · 6M · 7m. Memorising the formula lets you transpose the scale to any other root note quickly.
Where you will hear B♭ Half-Whole Diminished
Start with the music described above: listen for B♭ Half-Whole Diminished in it and transcribe a few short phrases by ear. It's the quickest way to learn how the scale sounds.
Questions people ask
What notes are in the B♭ Half-Whole Diminished scale?
The B♭ Half-Whole Diminished scale contains B♭, C♭, D♭, D, E, F, G and A♭.
What is the formula for the B♭ Half-Whole Diminished scale?
B♭ Half-Whole Diminished follows an eight-note symmetric scale alternating half-step then whole-step (1, ♭2, ♭3, 3, ♯4, 5, 6, ♭7).
Is B♭ Half-Whole Diminished a major or minor scale?
B♭ Half-Whole Diminished is a half-whole diminished scale. Octatonic scale alternating half then whole steps — symmetric, dissonant, the standard choice over a dominant 7♭9 chord in jazz.
What chords belong to the B♭ Half-Whole Diminished scale?
B♭ Half-Whole Diminished doesn't produce a standard seven-chord diatonic set. Use chords from a related diatonic scale instead.
Which genres use B♭ Half-Whole Diminished?
The half-whole diminished is the standard scale over a dominant 7♭9 chord in jazz. Its symmetry means a phrase transposed by minor third still fits the chord, perfect for fast harmonic motion.
How do you play the B♭ Half-Whole Diminished scale on the piano?
On the piano B♭ Half-Whole Diminished uses three black keys (B♭, D♭ and A♭) and five white. C♭ is the white key you'd normally call B.
How do I practise the B♭ Half-Whole Diminished scale?
Practise the scale starting from each chord tone of the underlying dominant 7♭9 (1, ♭3, ♭5, ♭♭7) — they're all four equivalent because of the symmetry, and that insight is what makes diminished playing fast and fluid.