Read left to right, 6th string to 1st: a number is a fret, 0 is an open string, x is a string you do not play.
- Index finger on the 1st fret of the high E string (1st).
- Middle finger on the 2nd fret of the A string (5th).
- Ring finger on the 3rd fret of the B string (2nd).
- Little finger on the 4th fret of the G string (3rd).
- Let the D string ring open.
- Do not play the low E string: start the strum from the A string.
String by string
What each string does in this shape, and which note of the chord it sounds. This is what to listen for when you pluck them one at a time.
| String | Fret | Finger | Note | In the chord |
|---|---|---|---|---|
| 6th (low E) | not played | — | — | — |
| 5th (A) | fret 2 | middle | B2 | root |
| 4th (D) | open | — | D3 | minor third |
| 3rd (G) | fret 4 | little | B3 | root |
| 2nd (B) | fret 3 | ring | D4 | minor third |
| 1st (high E) | fret 1 | index | F4 | flat fifth |
One string at a time: a chord strummed into a microphone is several notes at once, and a single string is something the page can hear exactly. A string in tune but on the wrong fret, or deadened by the finger beside it, shows up here and not on a tuner. Tap a string to check it again.
3 other ways to play Bdim
The same 3 notes, somewhere else on the neck. A different shape puts a different note on top, so each one colours the chord slightly differently — and one of them is usually nearer the chord you are coming from.
- x-x-9-10-12-10A shape at the 9th fret · four fingers
- xx9767A shape at the 6th fret · four fingers
- 75046xA shape at the 4th fret · four fingers
If the usual shape is too hard for now
x20401 is Bdim without the full barre — fewer strings, the same chord. It is a real voicing, not a cheat, and plenty of players keep using it.
Holding it cleanly
One string rings open next to fretted ones. Arch the fingers so they come down on their tips — a finger lying flat will deaden the open string beside it, and the chord loses a note without sounding obviously wrong.
It spans 4 frets. Bring the elbow in and let the hand turn slightly toward the body of the guitar; the stretch comes from the hand opening, not from the fingers reaching.
The lowest string is left out, because its open note is not in the chord. Aim the strum to start below it, or let the tip of a fretting finger rest against the unwanted string to keep it quiet.
The notes in Bdim
A diminished chord is built from the root (1), ♭3 and ♭5 of its root’s major scale. From B that gives B – D – F. Two minor thirds stacked: tense and unstable, a passing chord between two steadier ones.
The same root, other chords: B major, Bm, B7, Bmaj7, Bm7, Bsus2, Bsus4, Baug.
Keys that use Bdim
Bdim is built from the notes of 2 keys. Each link is that key’s full set of guitar chords — the ones that sound right next to this one.
Frequently asked questions
What notes are in a Bdim chord?
B diminished is three notes: B – D – F — the root, ♭3 and ♭5 of the B major scale. On guitar the shape x20431 sounds B2, D3, B3, D4 and F4, so some of those notes appear more than once.
What is the easiest way to play Bdim on guitar?
The usual shape is x20431 — an open-position shape, with four fingers. If that is out of reach for now, x20401 is the same chord without the full barre.
What is the difference between Bdim and Bm?
One note. Bdim is Bm with its fifth lowered a semitone, to F. That flattened fifth is a tritone above the root — the most unstable interval there is — which is why Bdim never sounds like a place to stop.
What keys is Bdim in?
Bdim is one of the seven chords of C major (as vii°) and A minor (as ii°).