B♭ minor 7th flat 5th chord on ukulele (B♭m7♭5)

Also called or written B♭m7♭5, B♭ or B♭ Half Diminished Minor 7

B♭ minor 7th flat 5th is built from B♭, D♭, F♭, and A♭. The 3rd fret shape uses a four-finger spread that feels tight for smaller hands.

3frB♭F♭A♭D♭GCEA
Positions on the neck1 of 4
Practice B♭ minor 7th flat 5th chord

How it is built

B♭RootD♭Minor thirdF♭Diminished fifthA♭Minor seventh

Formula 1, ♭3, ♭5, ♭7

Inversions

How do you play a B♭ minor 7th flat 5th chord on ukulele?

B♭ minor 7th flat 5th is played at the 3rd fret as 3 4 4 4: index finger on the G string at fret 3, middle finger on the C string at fret 4, ring finger on the E string at fret 4 and pinky finger on the A string at fret 4.

Full note and interval breakdown
StringFretFingerNote
4 (G)31B♭ (1)
3 (C)42F♭ (♭5)
2 (E)43A♭ (♭7)
1 (A)44D♭ (♭3)

AdvancedThe pinky must fret the A string at fret 4 while the ring finger holds the E string at the same fret, requiring a wide stretch.

B♭m7♭5/A♭ inversion

B♭ minor 7th flat 5th is played at the 6th fret as 6 8 6 7: index finger on the G string at fret 6, pinky finger on the C string at fret 8, middle finger on the E string at fret 6 and ring finger on the A string at fret 7.

Full note and interval breakdown
StringFretFingerNote
4 (G)61D♭ (♭3)
3 (C)84A♭ (♭7)
2 (E)62B♭ (1)
1 (A)73F♭ (♭5)

9th fret

B♭ minor 7th flat 5th is played at the 9th fret as 9 10 9 11: index finger on the G string at fret 9, ring finger on the C string at fret 10, middle finger on the E string at fret 9 and pinky finger on the A string at fret 11.

Full note and interval breakdown
StringFretFingerNote
4 (G)91F♭ (♭5)
3 (C)103B♭ (1)
2 (E)92D♭ (♭3)
1 (A)114A♭ (♭7)

B♭m7♭5/D♭ inversion

B♭ minor 7th flat 5th is played in open position as 1 1 0 1: index finger on the G string at fret 1, middle finger on the C string at fret 1 and ring finger on the A string at fret 1. The E string rings open.

Full note and interval breakdown
StringFretFingerNote
4 (G)11A♭ (♭7)
3 (C)12D♭ (♭3)
2 (E)openF♭ (♭5)
1 (A)13B♭ (1)

Why it sounds like that

B♭ minor 7th flat 5th uses the formula 1, ♭3, ♭5, ♭7. The diminished 5th between B♭ and F♭ creates the half-diminished sound. Compare it to B♭ minor 7th, which has a perfect 5th instead.

What goes wrong with B♭ minor 7th flat 5th?

  • Letting the pinky collapse and mute the A string.
  • Allowing the middle finger to touch the E string, causing a buzz.
  • Strumming too hard and making the F♭ note sound sharp.

When to use it

B♭ minor 7th flat 5th functions as the ii chord in A♭ natural minor, often moving to E♭ minor or A♭ minor. Its dark quality suits jazz ballads and minor blues.

Changing to and from B♭ minor 7th flat 5th

  • Sliding the shape down one fret to the 2nd fret gives A minor 7th flat 5th.
  • Sliding the shape up one fret to the 4th fret gives B minor 7th flat 5th.

Which voicing to use

The 3rd fret voicing has B♭ in the bass, giving a root-position sound. For a softer attack, try the B♭m7♭5/G♯ inversion with A♭ in the bass.

Other B♭ chords

Common questions

How is B♭ minor 7th flat 5th written?

B♭ minor 7th flat 5th is written as B♭m7♭5 or B♭. The ASCII root is Bb. It is also spelled A♯ in enharmonic notation for the same sounding root.

What is the difference between B♭ minor 7th flat 5th and B♭ diminished?

B♭ diminished is a triad with notes B♭, D♭, F♭. B♭ minor 7th flat 5th adds the minor 7th A♭.

Can B♭ minor 7th flat 5th be used in place of B♭ minor?

B♭ minor 7th flat 5th has a flattened fifth, so it sounds more tense than B♭ minor. Use it when you want a darker color.