Also written Bdim or B°
B diminished contains B, D, and F. The 7th-fret shape is a one-finger-per-string stretch that sits in the middle of the neck.
The same three notes, with a different one in the bass.
B diminished is built from the formula 1, ♭3, ♭5. The ♭5 interval gives the chord its tense, unstable quality. Compare B minor, which raises the fifth to F♯.
B diminished works as a passing chord between B minor and D major, or over an A natural minor line. The ♭5 interval creates a tritone that pulls toward the next chord, suiting jazz walk-ups and metal riffs.
The 7th-fret shape puts B in the bass for a root-position sound. The Bdim/D inversion at the 10th fret places D in the bass, which softens the chord's bite.
B diminished is played at the 7th fret as 7 8 9 7: index finger on the E string at fret 7, ring finger on the A string at fret 8, pinky finger on the D string at fret 9 and middle finger on the G string at fret 7.
Tip — The pinky must reach the 9th fret on the 2nd string while the middle finger holds the 7th fret on the 1st string.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 7 | 1 | B (1) |
| 3 (A) | 8 | 3 | F (♭5) |
| 2 (D) | 9 | 4 | B (1) |
| 1 (G) | 7 | 2 | D (♭3) |
B diminished is played at the 8th fret as 10 8 9 10: ring finger on the E string at fret 10, index finger on the A string at fret 8, middle finger on the D string at fret 9 and pinky finger on the G string at fret 10.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 10 | 3 | D (♭3) |
| 3 (A) | 8 | 1 | F (♭5) |
| 2 (D) | 9 | 2 | B (1) |
| 1 (G) | 10 | 4 | F (♭5) |
B diminished is played in open position as 1 2 0 ×: index finger on the E string at fret 1 and middle finger on the A string at fret 2. The D string rings open. The G string stays muted.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 1 | 1 | F (♭5) |
| 3 (A) | 2 | 2 | B (1) |
| 2 (D) | open | — | D (♭3) |
| 1 (G) | muted | — | — |
B diminished is played at the 7th fret as × 8 9 7: middle finger on the A string at fret 8, ring finger on the D string at fret 9 and index finger on the G string at fret 7. The E string stays muted.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | muted | — | — |
| 3 (A) | 8 | 2 | F (♭5) |
| 2 (D) | 9 | 3 | B (1) |
| 1 (G) | 7 | 1 | D (♭3) |
B diminished is played at the 12th fret as 13 14 12 ×: middle finger on the E string at fret 13, ring finger on the A string at fret 14 and index finger on the D string at fret 12. The G string stays muted.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 13 | 2 | F (♭5) |
| 3 (A) | 14 | 3 | B (1) |
| 2 (D) | 12 | 1 | D (♭3) |
| 1 (G) | muted | — | — |
Write B° or Bdim. The root is B, and the chord is spelled B–D–F.
The ♭5 interval creates a tritone with the root, which wants to resolve. This tension is what gives diminished chords their forward drive.
Only when you want that darker, more dissonant color. B diminished lowers the fifth, so it clashes with melodies that expect the perfect fifth F♯.