A Locrian

A1B♭♭2C♭3D4E♭♭5F♭6G♭7

The only mode of the major scale whose fifth is diminished, which is why its tonic chord cannot rest.

Written out

Fig. 2 · A Locrian, ascending

Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.

AHB♭WCWDHE♭WFWGWA

A Locrian is A, B♭, C, D, E♭, F and G, and back to A.

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

On the same tonic, A Phrygian differs from it by exactly one note.

Across the first twelve frets of the ukulele its notes fall in 31 places, which is what makes a scale a shape rather than a list.

Found by testing every chord in the catalogue against these 7 sounds, not chosen.