B♭ diminished seventh (B♭dim7) chord on mandolin

The B♭ diminished seventh chord (B♭dim7) is a diminished seventh chord (three stacked minor thirds), made of four notes: B♭ – D♭ – F♭ – A𝄫. The same chord with a different spelling: A♯ diminished seventh (A♯dim7).

Dots show:

Basic shapeeasy

Position 5medium

Position 8medium

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What the B♭dim7 chord sounds like

A diminished seventh is three stacked minor thirds, so it is symmetrical: four different roots give the same notes. A dramatic, tense passing chord.

Notes of the B♭dim7 chord

Degree	Note	Interval from the root
1	B♭	root
3	D♭	minor third (3 semitones)
5	F♭	diminished fifth (6 semitones)
7	A𝄫	diminished seventh (9 semitones)

How to play it – with fingering

Basic shape

String 1 (E): open (F♭5)
String 2 (A): fret 4, middle finger (D♭5)
String 3 (D): fret 5, ring finger (A𝄫4)
String 4 (G): fret 3, index finger (B♭3)

Position 5

String 1 (E): fret 6, ring finger (B♭5)
String 2 (A): fret 7, little finger (F♭5)
String 3 (D): fret 5, index finger (A𝄫4)
String 4 (G): fret 6, middle finger (D♭4)

Position 8

String 1 (E): fret 9, ring finger (D♭6)
String 2 (A): fret 10, little finger (A𝄫5)
String 3 (D): fret 8, index finger (B♭4)
String 4 (G): fret 9, middle finger (F♭4)

Tuning: G D A E, like a violin; every note is a pair of strings that you fret together. In the diagram, × means the string is not played, and a circle means an open string.

Similar chords and substitutes

If B♭dim7 is too hard, or you want a different colour in the same spot, these chords are worth a try.

Substitutes (by function)

F♯7 – an incomplete dominant: the diminished chord is the top of this seventh chord
B – where it leads (leading tone → root)

Same notes

C♯dim7 – the same notes with a different root
Edim7 – the same notes with a different root
Gdim7 – the same notes with a different root

Simpler versions

B♭dim – all 3 of its notes are in this chord

Frequently asked questions

What notes are in the B♭dim7 chord?

B♭, D♭, F♭, A𝄫. The root is B♭; the intervals of the other notes from the root: minor third, diminished fifth, diminished seventh.

What is the easiest way to play B♭dim7 on mandolin?

The easiest shape above is “Basic shape”, rated easy. We show 3 shapes, from open and easy versions to movable barre shapes higher up the neck.

How do I read the chord diagram?

Strings run from the lowest (left) to the highest (right) – tick “Left-handed” to mirror it. Rows are frets; a number at the side shows the starting fret. Dots are fingers (1 index, 2 middle, 3 ring, 4 little), a long bar is a barre, × means don't play that string and ○ means play it open.

Why do some songbooks write H instead of B?

In German and Central European notation, H is the note B, and B is the note B♭. So a “B” chord in a German or Hungarian songbook is B♭ in English notation, and an “H” chord is B. Always check which notation your chord chart uses.