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Fig. 1 · D# diminished (half–whole) on the keyboard

piano scale

D♯ diminished (half–whole)

D♯1E♭2F♯♭3F𝄪3G𝄪♯4A♯5B♯6C♯♭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 E♭ diminished (half–whole).

on guitaron ukulele

Written out

Fig. 2 · D# diminished (half–whole), ascending

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

D♯HEWF♯HF𝄪WG𝄪HA♯WB♯HC♯WD♯

What is true of it

D♯ diminished (half–whole) is D♯, E, F♯, F𝄪, G𝄪, A♯, B♯ and C♯, and back to D♯.

Its steps are H – W – H – W – H – W – H – W, where W is a whole step and H a half.

Written correctly it needs 9 alterations, F𝄪 and G𝄪 among them. That is what the letters force, and it is also why nobody writes music in this key: the same notes spelled from the other side are easier to read.

Chords made only of these notes

C♯dimdiminishedD♯majorD♯mminorD♯dimdiminishedD♯7dominant seventhD♯m7minor seventhD♯m7♭5half-diminished seventhEdimdiminished

Found by testing every chord in the catalogue against these 8 sounds, not chosen.

Other scales on D♯

D♯ whole tonesymmetricD♯ diminished (whole–half)symmetricD♯ majormajorD♯ natural minorminorD♯ harmonic minorminor

C dim H-WC♯ dim H-WD♭ dim H-WD dim H-WE dim H-WF dim H-WF♯ dim H-WG♭ dim H-Wall 374