semicord

Bbm(maj7) Bb minor-major seventh chord

Notes
Bb Db F A
Formula
1 b3 5 7
Semitones
0 3 7 11 above the root
Also written
A#m(maj7) (A# C# E# G##)
Other symbols
BbmM7, Bbm(Δ7), Bbmin(maj7)

Bb to Db is a minor third (3 semitones), Db to F is a major third (4 semitones), F to A is a major third (4 semitones). A minor triad with a major seventh, A, a half step below the root. The minor third Db and the major seventh make an augmented triad (Db F A) inside the chord, which gives it its tense, suspenseful sound.

Bbm(maj7) on the piano

C4D4E4F4G4A4B4C5D5E5F5G5A5B5C#4Eb4F#4Ab4Bb4Db5Eb5F#5Ab5Bb5C4BbC5DbFA

Root position from Bb4: Bb4, Db5, F5, A5. Middle C is C4.

Bbm(maj7) on the guitar

Standard tuning (E A D G B E). Strings run low E on the left to high e on the right, frets downwards; × is a muted string, ○ an open string, and each dot shows the note it sounds, with the root in blue-green. Every shape below has Bb as its lowest note.

×BbBbFFAADbDbFF
A-shape barre, root on the A string at fret 1
x 1 3 2 2 1 (low E to high e)
Sounds Bb2 F3 A3 Db4 F4
6frBbBb×AADbDbFF×
E-shape, root on the E string at fret 6
6 x 7 6 6 x (low E to high e)
Sounds Bb2 A3 Db4 F4

The E-shape and A-shape grips are movable: an E-shape chord's root is the note under your first finger on the low E string, an A-shape chord's root is the note on the A string. Slide the same grip up or down to play minor-major seventh chords on other roots.

Inversions of Bbm(maj7)

An inversion puts a note other than the root in the bass. The name is what semicord's chord finder calls those notes played bottom to top; a slash name like C/E means a C chord with E in the bass.

PositionNotes, bass firstNamedListen
Root positionBb Db F ABbm(maj7)
1st inversionDb F A BbBbm(maj7)/Db
2nd inversionF A Bb DbBbm(maj7)/F
3rd inversionA Bb Db FBbm/A (also read as Bbm(maj7)/A)

Where Bbm(maj7) fits

Bbm(maj7) is i(maj7) in Bb minor. Most often it is a passing chord in the descending line Bbm → Bbm(maj7) → Bbm7 → Bbm6, where one voice falls a half step at a time from Bb. The first four bars of the jazz standard "My Funny Valentine" (Cm, Cm(maj7), Cm7, Cm6 in C minor) are exactly that line.