guitar scale
D♭ harmonic major
Major with a flattened sixth: the mirror of harmonic minor, and the reason a major key can borrow a minor subdominant.
The same sounds spelled from the other side are C♯ harmonic major.
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
What is true of it
D♭ harmonic major is D♭, E♭, F, G♭, A♭, B♭♭ and C, and back to D♭.
Its steps are W – W – H – W – H – W+H – H, where W is a whole step and H a half.
Written correctly it needs 6 alterations, B♭♭ 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.
On the same tonic, D♭ major differs from it by exactly one note.
Across the first twelve frets of the guitar its notes fall in 43 places, which is what makes a scale a shape rather than a list.
Chords made only of these notes
Found by testing every chord in the catalogue against these 7 sounds, not chosen.
Other scales on D♭
C harm majD harm majD♯ harm majE♭ harm majE harm majF harm majF♯ harm majG♭ harm majall 374