C♯ half-diminished (C♯m7b5) chord on ukulele

The C♯ half-diminished chord (C♯m7b5) is a half-diminished seventh chord (a diminished triad plus a minor seventh), made of four notes: C♯ – E – G – B. The same chord with a different spelling: D♭ half-diminished (D♭m7b5).

Dots show:

Basic shapeeasy

Position 3medium

Position 6medium

Position 9medium

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What the C♯m7b5 chord sounds like

The half-diminished (m7b5) chord is a diminished triad with a minor seventh. In a minor key it sits on degree ii – the first chord of the minor ii–V–i.

Notes of the C♯m7b5 chord

Degree	Note	Interval from the root
1	C♯	root
3	E	minor third (3 semitones)
5	G	diminished fifth (6 semitones)
7	B	minor seventh (10 semitones)

How to play it – with fingering

Basic shape

String 1 (A): fret 2, middle finger (B4)
String 2 (E): open (E4)
String 3 (C): fret 1, index finger (C♯4)
String 4 (G): open (G4)

Position 3

String 1 (A): fret 4, little finger (C♯5)
String 2 (E): fret 3, index finger (G4)
String 3 (C): fret 4, ring finger (E4)
String 4 (G): fret 4, middle finger (B4)

Position 6

String 1 (A): fret 7, little finger (E5)
String 2 (E): fret 7, ring finger (B4)
String 3 (C): fret 7, middle finger (G4)
String 4 (G): fret 6, index finger (C♯5)

Tuning: G C E A (the G string is higher than the C – standard re-entrant ukulele tuning). In the diagram, × means the string is not played, and a circle means an open string.

Which keys is it in?

The C♯m7b5 chord is built from the notes of these keys (for minor keys, both the natural and the harmonic minor are considered):

D major: viiø7
B minor: iiø7

Similar chords and substitutes

If C♯m7b5 is too hard, or you want a different colour in the same spot, these chords are worth a try.

Substitutes (by function)

A9 – a rootless dominant ninth: the same notes over a root a major third lower
F♯7 – the next chord in a minor ii–V–i (V)

Same notes

Em6 – the same notes with a different root

Simpler versions

C♯dim – all 3 of its notes are in this chord

Frequently asked questions

What notes are in the C♯m7b5 chord?

C♯, E, G, B. The root is C♯; the intervals of the other notes from the root: minor third, diminished fifth, minor seventh.

What is the easiest way to play C♯m7b5 on ukulele?

The easiest shape above is “Basic shape”, rated easy. We show 4 shapes, from open and easy versions to movable barre shapes higher up the neck.

How do I read the chord diagram?

Strings run from the lowest (left) to the highest (right) – tick “Left-handed” to mirror it. Rows are frets; a number at the side shows the starting fret. Dots are fingers (1 index, 2 middle, 3 ring, 4 little), a long bar is a barre, × means don't play that string and ○ means play it open.

How is the C♯m7b5 chord written?

The chord symbol is C♯m7b5 (also written C#m7b5), and its full name is C♯ half-diminished.