The Bb half-diminished / A# half-diminished chord (Bbm7b5) is made of the notes Bb, Db, Fb and Ab. It is built from the root Bb with a minor third, a diminished fifth and a minor seventh.
The half-diminished chord (m7b5) is the second-degree chord of minor keys; very common in jazz.
Bb half-diminished
Notes: Bb – Db – Fb – Ab
Guitar — positions on the neck
Piano — root position and inversions
Fingerings and positions
On guitar, this chord can be played in 4 ways along the neck. It is most often played with a barre. Example fingering (from the low E string to the high E string, x = muted string): x1212x. On piano, the right hand plays 4 notes, in root position or in an inversion.
Notes and intervals
Note
Interval
Bb
root
Db
minor third
Fb
diminished fifth
Ab
minor seventh
In which keys? The Bb half-diminished chord is the viiø7 of B major and the iiø7 of Ab minor.
What are the notes of the Bb half-diminished chord?
The notes of the Bb half-diminished chord (Bbm7b5) are Bb, Db, Fb and Ab.
How do you play the Bb half-diminished chord on guitar?
On guitar, this chord can be played in 4 ways along the neck. It is most often played with a barre. Example fingering (from the low E string to the high E string, x = muted string): x1212x.
How is the Bb half-diminished chord built?
The Bb half-diminished / A# half-diminished chord (Bbm7b5) is made of the notes Bb, Db, Fb and Ab. It is built from the root Bb with a minor third, a diminished fifth and a minor seventh.
Are Bb and A# the same chord?
Yes: Bb and A# are the same note (they are called enharmonic), so Bb half-diminished / A# half-diminished is played exactly the same way, with the same fingerings.