Bdim guitar chord
Three notes across one string set.
- Tap a note to hear it
- Arrows change position
- Fingers, notes or intervals
- Play the chord
About Bdim — triad voicings
Bdim is B, D and F — Bm with the fifth lowered as well.
It sounds compressed and unstable in every direction. Rarely a destination; it is where a line passes through on the way somewhere.
Bdim notes and formula
| B | D | F |
|---|---|---|
| 1 | ♭3 | ♭5 |
Unstable — it does not sit still.
Also written B°, Bo or B diminished. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play Bdim
Three notes on one string set. No seventh, so nothing is claimed about the chord beyond its quality.
Thin on their own, excellent over a bass line or against someone else’s harmony.
Bdim has 48 of them, on the bottom three strings, the middle four strings, the low-middle three, the high-middle three, the top three strings, the top four strings, the bottom four strings, strings 5-3-2-1 and strings 6-4-3-2, from open position up to the 12th — every inversion the chord has: B in the bass, D in the bass and F in the bass. The one to learn first is the F shape at the nut, which is the easiest grip here.
6 of them sit on the bottom three strings, so you can run the inversions up one set without changing strings — which is the whole reason to learn them as a family rather than as separate grips.
Start with x20x01 — 2 open strings and only 2 fretted notes. 1 of the 5 shapes here sits in open position. None of them needs a barre. Together they cover the neck from the 1st fret to the 14th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x20x01 | open position | B, root position | F | 2 open strings |
| x2343x | 2nd fret | B, root position | D | all fretted |
| 75x76x | 5th fret | B, root position | F | all fretted |
| x-x-9-10-x-10 | 9th fret | B, root position | D | all fretted |
| x-14-12-x-12-13 | 12th fret | B, root position | F | all fretted |
The same notes rebuilt from scratch give 6 open string voicings, each on its own page.
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).
How to use Bdim
In which keys. Every note of Bdim belongs to C major (the vii°, the leading tone) and A minor (the ii°, the supertonic).
What to play over Bdim
Every note of Bdim is in B blues, B locrian, B altered, B diminished and B half-whole diminished.
Chords near Bdim
Change one note of Bdim and you have Bm (the flat fifth becomes a fifth), Bdim7 (add the sixth), Bm7b5 (add the flat seventh) or BmMaj7b5 (add the major seventh).
Bdim is a diminished chord — root, minor third, flat fifth. Diminished and half-diminished chords on every root.
On Bdim’s sound and use this page follows Stefan Kostka, Dorothy Payne & Byron Almén, Tonal Harmony (McGraw-Hill, 8th ed., 2018). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.