Chords in Ab Locrian

Ab Locrian is built from the notes Ab, Bbb, Cb, Db, Ebb, Fb and Gb. Its scale carries 9 flats. Harmonising that scale in thirds gives seven chords — 3 majors, 3 minors and 1 diminished — starting on Abdim as the iø. The chord on the fifth degree is Ebb, a major bV, so Ab Locrian has the leading tone that makes a Ebb-to-Abdim cadence sound final.

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