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B♭ diminished major 7th chord on ukulele (B♭dimMaj7)
Also called or written B♭dimMaj7, B♭dimM7, B♭°M7, B♭ augmented minor seventh or B♭ minor seventh sharp five
B♭ diminished major 7th contains B♭, D♭, F♭ and A. The open position uses two open strings, but the fretted notes still require careful fingering.
How it is built
Formula 1, ♭3, ♭5, 7
How do you play a B♭ diminished major 7th chord on ukulele?
B♭ diminished major 7th is played in open position as 3 1 0 0: middle finger on the G string at fret 3 and index finger on the C string at fret 1. The E and A strings ring open.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 3 | 2 | B♭ (1) |
| 3 (C) | 1 | 1 | D♭ (♭3) |
| 2 (E) | open | — | F♭ (♭5) |
| 1 (A) | open | — | A (7) |
AdvancedThe middle finger on G string fret 3 must arch over the open A string without muting it.
B♭dimM7/F♭ inversion
B♭ diminished major 7th is played at the 3rd fret as 3 4 5 4: index finger on the G string at fret 3, middle finger on the C string at fret 4, pinky finger on the E string at fret 5 and ring finger on the A string at fret 4.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 3 | 1 | B♭ (1) |
| 3 (C) | 4 | 2 | F♭ (♭5) |
| 2 (E) | 5 | 4 | A (7) |
| 1 (A) | 4 | 3 | D♭ (♭3) |
B♭dimM7/D♭ inversion · B♭ on top
B♭ diminished major 7th is played in open position as 2 1 0 1: ring finger on the G string at fret 2, index finger on the C string at fret 1 and middle finger on the A string at fret 1. The E string rings open.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 2 | 3 | A (7) |
| 3 (C) | 1 | 1 | D♭ (♭3) |
| 2 (E) | open | — | F♭ (♭5) |
| 1 (A) | 1 | 2 | B♭ (1) |
Why it sounds like that
B♭ diminished major 7th is built 1, ♭3, ♭5, 7. The diminished 5th between B♭ and F♭ creates a tritone, while the major 7th A sits a semitone below the root. Compare it with B♭ minor 7th flat 5th, which has A♭ instead of A.
What goes wrong with B♭ diminished major 7th?
- Letting the middle finger lean on the open A string and dampen it.
- Fretting the C string too far behind the fret, causing a buzz.
When to use it
B♭ diminished major 7th appears in B♭ minor as a passing chord, resolving to B♭ minor or B♭ major. Its dissonance suits jazz and whole-half scale runs.
Changing to and from B♭ diminished major 7th
- Slide the fretted notes up one fret to the 3rd fret to reach B diminished major 7th.
Which voicing to use
The open position keeps B♭ in the bass via the G string fret 3. The 3rd fret position offers the same bass note but higher register, while the B♭dimM7/A inversion puts A in the bass for a different color.
Other B♭ chords
Common questions
How is B♭ diminished major 7th written?
B♭ diminished major 7th is written B♭°M7 or B♭dimM7. The ASCII root spelling is Bb. It is also spelled A♯ in enharmonic notation for the same sounding root.
What is the difference between B♭ diminished major 7th and B♭ minor 7th flat 5th?
B♭ diminished major 7th has a major 7th, A. B♭ minor 7th flat 5th has a minor 7th, A♭.
Why does B♭ diminished major 7th use F♭ instead of E?
B♭ diminished major 7th uses F♭ because the diminished 5th from B♭ is six semitones, and F♭ is the correct spelling in a B♭ context.