Bdim 8-string bass chord

How to play Bdim on 8-string bass

The most common way, the first shape above: your index finger on the E string at the 1st fret and your ring finger on the A string at the 2nd fret. Let the B and D strings ring open. Don’t play the F♯, G, C and F strings.

From the F♯ string x 0 1 2 0 x x x (x: not played, 0: open)

What notes are in Bdim?

Bdim, B diminished, is B, D and F: the root (B), the minor third (D) and the diminished fifth (F). Its formula is 1 ♭3 ♭5.

What is the difference between Bdim, Bm7♭5 and Bdim7?

Bdim is three notes, B, D and F. Bm7♭5 adds the minor seventh, A; Bdim7 adds the diminished seventh, A♭, a half step lower.

Where does Bdim go?

Most often up a half step, to C: it is the chord on the seventh note of a major key, leading back to the tonic.

Keys with Bdim

Bdim is the vii° chord in C major and the ii° chord in A minor.