Bbdim7 guitar chord
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.
- Tap a note to hear it
- Arrows change position
- Fingers, notes or intervals
- Play the chord
About Bbdim7 — open string voicings
Bbdim7 is Bb, Db, Fb and G — Bbdim with a diminished seventh stacked on top.
It sounds suspenseful and rootless. Three stacked minor thirds divide the octave evenly, so the same four notes spell four dim7 chords and the shape repeats every three frets.
Bbdim7 notes and formula
| Bb | Db | Fb | G |
|---|---|---|---|
| 1 | ♭3 | ♭5 | ♭♭7 |
Leading-tone or passing chord — it can resolve almost anywhere.
Also written Bb°7, Bbo7 or Bb diminished 7. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play Bbdim7
An open string left ringing against a fretted grip. It costs no finger, so it can sound a note the closed shape has none left for: a tension on top, or a pedal root underneath.
These belong to their key rather than to a shape: they cannot be moved up the neck. D, A, G and E have many; E♭ has a handful.
Bbdim7 has 6 of them, on strings 6-5-4-3-2-1, strings 6-5-4-3-2, the bottom four strings, strings 6-4-3-2-1 and the top four strings, from the 2nd fret up to the 5th — all in one inversion, so the bass note never moves. The one to learn first is the Fb shape at the 2nd fret, which is the easiest grip here.
Start with x12020 — no barre and 2 open strings. 1 of the 8 shapes here sits in open position. 2 of the 8 need a barre. Together they cover the neck from the 1st fret to the 15th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x12020 | open position | Bb, root position | Fb | 2 open strings |
| xx2323 | 2nd fret | Fb, 2nd inversion | G | all fretted |
| 6x5656 | 5th fret | Bb, root position | Bb | barred |
| 678686 | 6th fret | Bb, root position | Bb | barred |
| xx8989 | 8th fret | Bb, root position | Db | all fretted |
| x-x-11-12-11-12 | 11th fret | Db, 1st inversion | Fb | all fretted |
| x-13-14-12-14-12 | 12th fret | Bb, root position | Fb | all fretted |
| x-x-14-15-14-15 | 14th fret | Fb, 2nd inversion | G | all fretted |
The same notes rebuilt from scratch give 6 shell, 14 drop 2 and 10 drop 3 voicings, each on its own page.
Tensions. A shell of Bbdim7, root, third and seventh, leaves a string free, and the tones that belong over it are the 9 (C), the 11 (Eb), the b13 (Gb) and the maj7 (A).
How to use Bbdim7
A diminished seventh divides the octave evenly, so Bbdim7 has no single root and no single destination: it can lead to Eb or to B, and it is the same four notes either way.
What to play over Bbdim7
Every note of Bbdim7 is in Bb diminished and Bb half-whole diminished.
Chords near Bbdim7
Change one note of Bbdim7 and you have Bbdim (drop the sixth), Bbm6 (the flat fifth becomes a fifth), Bbm7b5 (the sixth becomes a flat seventh) or BbmMaj7b5 (the sixth becomes a major seventh).
Bbdim7 is a diminished chord — root, minor third, flat fifth. Diminished and half-diminished chords on every root.
On Bbdim7’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.