G♯ diminished (half–whole)

G♯1A♭2B♭3B♯3C𝄪♯4D♯5E♯6F♯♭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).

on ukulele on piano

Written out

Fig. 2 · G# 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

G♯HAWBHB♯WC𝄪HD♯WE♯HF♯WG♯

What is true of it

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

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 7 alterations, C𝄪 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.

Across the first twelve frets of the guitar its notes fall in 51 places, which is what makes a scale a shape rather than a list.

Chords made only of these notes

D♯dimdiminished F♯dimdiminished G♯major G♯mminor G♯dimdiminished G♯7dominant seventh G♯m7minor seventh G♯m7♭5half-diminished seventh

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

Other scales on G♯

G♯ whole tonesymmetric G♯ diminished (whole–half)symmetric G♯ majormajor G♯ natural minorminor G♯ harmonic minorminor

C dim H-W C♯ dim H-W D♭ dim H-W D dim H-W D♯ dim H-W E♭ dim H-W E dim H-W F dim H-W all 374