piano scale
B♭ diminished (half–whole)
B♭1C♭♭2D♭♭3D3E♯4F5G6A♭♭7
The same eight notes started a half step earlier: the scale that spells a dominant seventh with a flat ninth and a sharp ninth at once.
The same sounds spelled from the other side are A♯ diminished (half–whole).
Written out
Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.
The step pattern
B♭HC♭WD♭HDWEHFWGHA♭WB♭
What is true of it
B♭ diminished (half–whole) is B♭, C♭, D♭, D, E, F, G and A♭, and back to B♭.
Its steps are H – W – H – W – H – W – H – W, where W is a whole step and H a half.
Chords made only of these notes
D♭majorD♭mminorD♭dimdiminishedD♭7dominant seventhD♭m7minor seventhD♭m7♭5half-diminished seventhDdimdiminishedEmajor
Found by testing every chord in the catalogue against these 8 sounds, not chosen.
Other scales on B♭
B♭ whole tonesymmetricB♭ diminished (whole–half)symmetricB♭ majormajorB♭ natural minorminorB♭ harmonic minorminor
C dim H-WC♯ dim H-WD♭ dim H-WD dim H-WD♯ dim H-WE♭ dim H-WE dim H-WF dim H-Wall 374