Key
Chords in B Dorian
B Dorian is built from the notes B, C#, D, E, F#, G# and A. Its scale carries 3 sharps. Harmonising that scale in thirds gives seven chords — 3 majors, 3 minors and 1 diminished — starting on Bm as the i. The chord on the fifth degree is F#m rather than a major V, so B Dorian has no leading tone and resolves by step and colour instead of by dominant pull — the sound that separates it from a plain B major.
Beyond those seven, B Dorian commonly borrows B (I), D#m (iii), E (IV), F# (V) and G#m (vi) from the parallel major — the mixture chords that give a progression somewhere unexpected to go.
The seven chords
Extended to four notes each, the same seven degrees give Bm7, C#m7, Dmaj7, E7, F#m7, G#m7b5, Amaj7.
Borrowed chords
Capo 2 and play A Dorian shapes to sound B Dorian.
All eight capo positions for B Dorian →