C#m7b5 guitar chord
An open string left ringing against a fretted grip. Because it costs no finger, it sounds a note the closed shape has none left for -- a tension on top, or a pedal root underneath. Either a familiar grip with open strings added, or a shape so sparse the open strings carry the chord. These belong to their key rather than to a shape, so D, A, G and E have many and Eb a handful.
- Tap a note to hear it
- Arrows change position
- Fingers, notes or intervals
- Play the chord
About C#m7b5 — open string voicings
C#m7b5 is C#, E, G and B — C#m7 with the fifth lowered a semitone.
It sounds hollow, and unmistakably going somewhere. Almost always the first chord of a minor ii–V–i, so it walks straight into an altered dominant.
C#m7b5 notes and formula
| C# | E | G | B |
|---|---|---|---|
| 1 | ♭3 | ♭5 | ♭7 |
Pre-dominant — the ii of a minor key.
Also written C#ø, C#ø7, C#m7-5, C#m7(b5) or C# half diminished. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play C#m7b5
An open string left ringing against a fretted grip. It costs no finger, so it can sound a note the closed shape has none left for: a tension on top, or a pedal root underneath.
These belong to their key rather than to a shape: they cannot be moved up the neck. D, A, G and E have many; E♭ has a handful.
C#m7b5 has 6 of them, on strings 6-5-4-3-2-1, strings 6-5-4-3-2, strings 5-4-3-2-1 and strings 6-4-3-2-1, from the 2nd fret up to the 4th — every inversion the chord has: C# in the bass and E in the bass. The one to learn first is the E shape at the 2nd fret, which is the easiest grip here.
Start with x4545x — no barre and low, at the 4th fret. None of the shapes for C#m7b5 uses an open string, so every one of them is movable; the lowest sits at the 2nd fret. 3 of the 7 need a barre. Together they cover the neck from the 2nd fret to the 12th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x42423 | 2nd fret | C#, root position | G | all fretted |
| x4545x | 4th fret | C#, root position | E | all fretted |
| xx5657 | 5th fret | G, 2nd inversion | B | all fretted |
| 9xx987 | 7th fret | C#, root position | B | all fretted |
| 9x998x | 8th fret | C#, root position | G | barred |
| 9-10-11-9-12-9 | 9th fret | C#, root position | C# | barred |
| x-x-11-12-12-12 | 11th fret | C#, root position | E | barred |
The same notes rebuilt from scratch give 5 shell, 13 drop 2 and 9 drop 3 voicings, each on its own page.
Tensions. A shell of C#m7b5, root, third and seventh, leaves a string free, and the tones that belong over it are the 11 (F#) and the b13 (A).
How to use C#m7b5
C#m7b5 is the ii of B minor, which is where it is nearly always found: half-diminished, then an altered dominant, then the minor tonic.
In which keys. Every note of C#m7b5 belongs to D major (the vii°, the leading tone) and B minor (the ii°, the supertonic).
What to play over C#m7b5
Every note of C#m7b5 is in C# blues, C# locrian, C# altered and C# half-whole diminished.
Chords near C#m7b5
Change one note of C#m7b5 and you have C#dim (drop the flat seventh), C#dim7 (the flat seventh becomes a sixth), C#m7 (the flat fifth becomes a fifth), C#mMaj7b5 (the flat seventh becomes a major seventh) or C#7b5 (the minor third becomes a major third).
C#m7b5 is a diminished chord — root, minor third, flat fifth. Diminished and half-diminished chords on every root.
On C#m7b5’s sound and use this page follows Mark Levine, The Jazz Theory Book (Sher Music, 1995). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.