piano scale
D♭ Dorian
D♭1E♭2F♭♭3G♭4A♭5B♭6C♭♭7
Minor with a natural sixth. The second mode of the major scale.
The same sounds spelled from the other side are C♯ Dorian.
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
D♭WE♭HF♭WG♭WA♭WB♭HC♭WD♭
What is true of it
D♭ Dorian is D♭, E♭, F♭, G♭, A♭, B♭ and C♭, and back to D♭.
Its steps are W – H – W – W – W – H – W, where W is a whole step and H a half.
It costs 7 alterations to write — near the limit of what a key signature can carry.
On the same tonic, D♭ natural minor differs from it by exactly one note.
Chords made only of these notes
D♭mminorD♭m7minor seventhE♭mminorE♭m7minor seventhG♭majorG♭7dominant seventhA♭mminorA♭m7minor seventh
Found by testing every chord in the catalogue against these 7 sounds, not chosen.