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B diminished major 7th chord on ukulele (BdimMaj7)
Also called or written BdimMaj7, BdimM7, B°M7, B augmented minor seventh or B minor seventh sharp five
B diminished major 7th contains B, D, F and A♯. The 4th fret shape mirrors the A shape up two frets, but the stretch remains demanding.
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 at the 4th fret as 4 5 6 5: index finger on the G string at fret 4, middle finger on the C string at fret 5, pinky finger on the E string at fret 6 and ring finger on the A string at fret 5.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 4 | 1 | B (1) |
| 3 (C) | 5 | 2 | F (♭5) |
| 2 (E) | 6 | 4 | A♯ (7) |
| 1 (A) | 5 | 3 | D (♭3) |
AdvancedThe pinky must reach fret 6 on the E string while the ring finger holds fret 5 on the A string, a two-fret stretch.
BdimM7/D inversion
B diminished major 7th is played at the 1st fret as 3 2 1 2: pinky finger on the G string at fret 3, middle finger on the C string at fret 2, index finger on the E string at fret 1 and ring finger on the A string at fret 2.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 3 | 4 | A♯ (7) |
| 3 (C) | 2 | 2 | D (♭3) |
| 2 (E) | 1 | 1 | F (♭5) |
| 1 (A) | 2 | 3 | B (1) |
Why it sounds like that
B diminished major 7th is built 1, ♭3, ♭5, 7. The diminished 5th between B and F is a tritone, and the major 7th A♯ is a leading tone to B. Compare it with B minor 7th flat 5th, which has A instead of A♯.
What goes wrong with B diminished major 7th?
- Letting the pinky collapse and mute the A string.
- Pressing the index finger too far from the fret, causing the G string to buzz.
When to use it
B diminished major 7th functions as a passing chord in B minor, resolving to B minor or B major. Its leading tone suits gypsy minor and chromatic lines.
Changing to and from B diminished major 7th
- Slide the shape down two frets to the 2nd fret to reach A diminished major 7th.
Which voicing to use
The 4th fret position keeps B in the bass. The BdimM7/A♯ inversion puts A♯ in the bass, creating a darker sound with the major 7th on the bottom.
Other B chords
Common questions
How is B diminished major 7th written?
B diminished major 7th is written B°M7 or BdimM7.
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 sound unstable?
B diminished major 7th contains a tritone between B and F, and the major 7th A♯ creates a strong pull to the root B.