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B♭ diminished major 7th chord on guitar (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 shape uses four fretted notes and an open high E, requiring careful finger placement.
How it is built
Formula 1, ♭3, ♭5, 7
- Root positionB♭–D♭–F♭–AB♭dimMaj7×-1-2-2-2-0
- First inversionD♭–F♭–A–B♭B♭dimMaj7/D♭×-4-×-3-5-5
- Second inversionF♭–A–B♭–D♭B♭dimMaj7/F♭0-0-2-3-2-0
- Third inversionA–B♭–D♭–F♭B♭dimMaj7/A×-0-2-3-2-0
How do you play a B♭ diminished major 7th chord on guitar?
B♭ diminished major 7th is played in open position as × 1 2 2 2 0: index finger on the A string at fret 1, middle finger on the D string at fret 2, ring finger on the G string at fret 2 and pinky finger on the B string at fret 2. The high e string rings open. The low E string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | muted | — | — |
| 5 (A) | 1 | 1 | B♭ (1) |
| 4 (D) | 2 | 2 | F♭ (♭5) |
| 3 (G) | 2 | 3 | A (7) |
| 2 (B) | 2 | 4 | D♭ (♭3) |
| 1 (e) | open | — | F♭ (♭5) |
AdvancedFretting four strings with separate fingers while keeping the high E open demands precise finger independence.
6th fret
B♭ diminished major 7th is played at the 6th fret as 6 7 7 6 × ×: index finger on the low E string at fret 6, ring finger on the A string at fret 7, pinky finger on the D string at fret 7 and middle finger on the G string at fret 6. The B and high e strings stay muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 6 | 1 | B♭ (1) |
| 5 (A) | 7 | 3 | F♭ (♭5) |
| 4 (D) | 7 | 4 | A (7) |
| 3 (G) | 6 | 2 | D♭ (♭3) |
| 2 (B) | muted | — | — |
| 1 (e) | muted | — | — |
8th fret
B♭ diminished major 7th is played at the 8th fret as × × 8 9 10 9: index finger on the D string at fret 8, middle finger on the G string at fret 9, pinky finger on the B string at fret 10 and ring finger on the high e string at fret 9. The low E and A strings stay muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | muted | — | — |
| 5 (A) | muted | — | — |
| 4 (D) | 8 | 1 | B♭ (1) |
| 3 (G) | 9 | 2 | F♭ (♭5) |
| 2 (B) | 10 | 4 | A (7) |
| 1 (e) | 9 | 3 | D♭ (♭3) |
13th fret
B♭ diminished major 7th is played at the 13th fret as × 13 14 14 14 ×: index finger on the A string at fret 13, middle finger on the D string at fret 14, ring finger on the G string at fret 14 and pinky finger on the B string at fret 14. The low E and high e strings stay muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | muted | — | — |
| 5 (A) | 13 | 1 | B♭ (1) |
| 4 (D) | 14 | 2 | F♭ (♭5) |
| 3 (G) | 14 | 3 | A (7) |
| 2 (B) | 14 | 4 | D♭ (♭3) |
| 1 (e) | muted | — | — |
B♭dimM7/D♭ inversion
B♭ diminished major 7th is played at the 3rd fret as × 4 × 3 5 5: middle finger on the A string at fret 4, index finger on the G string at fret 3, ring finger on the B string at fret 5 and pinky finger on the high e string at fret 5. The low E and D strings stay muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | muted | — | — |
| 5 (A) | 4 | 2 | D♭ (♭3) |
| 4 (D) | muted | — | — |
| 3 (G) | 3 | 1 | B♭ (1) |
| 2 (B) | 5 | 3 | F♭ (♭5) |
| 1 (e) | 5 | 4 | A (7) |
Why it sounds like that
B♭ diminished major 7th is built from the formula 1, ♭3, ♭5, 7. The diminished 5th between B♭ and F♭ gives the chord its dark color, while the major 7th A adds a bright edge. Compare it to B♭ minor 7th flat 5th, which lowers the 7th to A♭.
What goes wrong with B♭ diminished major 7th?
- Letting the low E string ring out, which adds an E that is not part of B♭ diminished major 7th.
- Accidentally muting the open high E string with your pinky.
- Fretting the D string too close to the fret, causing a buzz.
When to use it
B♭ diminished major 7th appears in B♭ minor progressions as a passing chord, such as B♭ minor–B♭ diminished major 7th–B♭ minor 7th. Its unstable sound fits jazz and dramatic film cues. Resolve it to B♭ minor or B♭ 7th.
Changing to and from B♭ diminished major 7th
- Sliding the shape down two frets to the 4th fret gives A♭ diminished major 7th.
- Sliding the shape down one fret to the 5th fret gives A diminished major 7th.
Which voicing to use
The open position keeps the bass on B♭, while the 6th fret voicing moves the same notes up the neck. The B♭dimM7/D♭ inversion places D♭ in the bass, creating a darker, less stable sound.
Other B♭ chords
Common questions
How is B♭ diminished major 7th written?
B♭ diminished major 7th is written B♭°M7 or B♭dimM7. The root is B♭, with ASCII spelling 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), while B♭ minor 7th flat 5th has a minor 7th (A♭). The major 7th creates a stronger leading tone.
Why does B♭ diminished major 7th sound so tense?
The diminished 5th between B♭ and F♭ creates a tritone, and the major 7th A adds a leading tone. Together they produce a highly dissonant, unresolved sound.