Chords in Db Dorian

Db Dorian is built from the notes Db, Eb, Fb, Gb, Ab, Bb and Cb. Its scale carries 7 flats. Harmonising that scale in thirds gives seven chords — 3 majors, 3 minors and 1 diminished — starting on Dbm as the i. The chord on the fifth degree is Abm rather than a major V, so Db Dorian has no leading tone and resolves by step and color instead of by dominant pull — the sound that separates it from a plain Db major.

Beyond those seven, Db Dorian commonly borrows Db (I), Fm (iii), Gb (IV), Ab (V) and Bbm (vi) from the parallel major — the mixture chords that give a progression somewhere unexpected to go.