Bdim

Bdim is B, D and F, a diminished triad. The shape this page opens on is written x20x01, lowest string first.

Note by note. B is the root, D is the minor third and F is the flat fifth.

Also written B°, Bo or B diminished. The same chord either way; which spelling you meet depends on who wrote the chart.

There are 5 common shapes for Bdim on the guitar, and 54 derived voicings in 2 families.

One note away. Change a single note of Bdim and you have Bm (with one note moved), Bdim7 (with one note added), Bm7b5 (with one note added) or BmMaj7b5 (with one note added).

In which keys. Every note of Bdim belongs to C major (the vii°) and A minor (the ii°).

The common shapes, written lowest string first: x20x01, x2343x, 75x76x, x-x-9-10-x-10, x-14-12-x-12-13.

Under the hand. 1 of the 5 shapes here sits in open position, and the first uses 2 open strings with 2 left unplayed. None of them needs a barre. Together they cover the neck from the 1st fret to the 14th.

Triad. Three notes across one string set. Bdim has 120xxx, x2343x, x534xx, xx343x, x5343x, xx046x, xxx767, xx0767.

Open string. An open string left ringing against a fretted grip. Because it costs no finger, it sounds a note the closed shape has none left for -- a tension on top, or a pedal root underneath. Either a familiar grip with open strings added, or a shape so sparse the open strings carry the chord. These belong to their key rather than to a shape, so D, A, G and E have many and Eb a handful. Bdim has x23430, x53400, 7x0060, x53000, xx0067, xx0460.

Tensions. A shell of Bdim, root, third and seventh, leaves a string free, and the tones that belong over it are the 11 (E) and the b13 (G).

What kind of chord this is. Bdim is a diminished chord — root, minor third, flat fifth. diminished and half-diminished chords on every root, and what they are for.

The common shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.