B♭ Minor
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0 - 3 - 7Root + minor 3rd + perfect 5th
About B♭ Minor
B♭ minor has five flats and no open strings to help. Its notes — B♭, D♭, F — sit outside everything the guitar offers freely, and every voicing is a barre. It is the chord that makes a guitarist reach for a capo faster than any other.
The notes
B♭, D♭, F — root, minor third, perfect fifth. The D♭ is the outsider even among flats: it appears in only the darkest key signatures, and nothing on the fretboard suggests it.
Raise the D♭ to D and the chord becomes B♭ major, which is merely difficult rather than remote. The minor form is harder to hear and harder to place.
Positions
First fret with the root on the A string, or sixth fret with the root on the low E. Both are full barres; the sixth-fret version is the one most players use, because the first fret with a minor shape is punishing.
The practical alternative is a capo at the first fret and an A minor shape, or at the third with a G minor grip. Recordings in this key were mostly made that way.
Where it shows up
As the ii of A♭ major and the vi of D♭ — keys that belong to piano, brass and production rather than to guitar.
On guitar it usually arrives through transposition: a song written elsewhere moved to fit a singer. That is worth knowing, because it means the awkwardness is incidental, not musical.
It is also common in gospel and soul, where the piano leads and the guitar follows. A player who learns the sixth-fret shape and the capo alternative has everything the key demands without further study.