Also written C♯m7♭5, C♯ or C♯ Half Diminished Minor 7
C♯ minor 7th flat 5th is built from C♯, E, G, B. The open voicing places the root on the C string and the ♭7 on the A string, leaving two open strings ringing.
The same three notes, with a different one in the bass.
C♯ minor 7th flat 5th stacks a minor 3rd, a diminished 5th, and a minor 7th over C♯. The diminished 5th between C♯ and G creates the chord's tense, unresolved quality. Compare it to C♯ minor 7th, which raises the ♭5 to a perfect 5th.
C♯ minor 7th flat 5th fits the ii chord in B natural minor and the vii chord in D major. Use it in jazz and blues progressions where a half-diminished sound is needed, such as moving to C♯ minor or E major.
The open voicing keeps C♯ in the bass and is easiest to grab. The C♯m7♭5/E inversion at the 4th fret puts E in the bass for a darker register, while the C♯m7♭5/G inversion at the 6th fret raises the tension with G in the bass.
C♯ minor 7th flat 5th is played in open position as 0 1 0 2: index finger on the C string at fret 1 and middle finger on the A string at fret 2. The G and E strings ring open.
Tip — The open voicing requires precise finger placement to avoid muting the adjacent open E string while fretting the C string.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | open | — | G (♭5) |
| 3 (C) | 1 | 1 | C♯ (1) |
| 2 (E) | open | — | E (♭3) |
| 1 (A) | 2 | 2 | B (♭7) |
C♯ minor 7th flat 5th is played at the 3rd fret as 4 4 3 4: middle finger on the G string at fret 4, ring finger on the C string at fret 4, index finger on the E string at fret 3 and pinky finger on the A string at fret 4.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 4 | 2 | B (♭7) |
| 3 (C) | 4 | 3 | E (♭3) |
| 2 (E) | 3 | 1 | G (♭5) |
| 1 (A) | 4 | 4 | C♯ (1) |
C♯ minor 7th flat 5th is played at the 6th fret as 6 7 7 7: index finger on the G string at fret 6, middle finger on the C string at fret 7, ring finger on the E string at fret 7 and pinky finger on the A string at fret 7.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 6 | 1 | C♯ (1) |
| 3 (C) | 7 | 2 | G (♭5) |
| 2 (E) | 7 | 3 | B (♭7) |
| 1 (A) | 7 | 4 | E (♭3) |
C♯ minor 7th flat 5th is played at the 9th fret as 9 11 9 10: index finger on the G string at fret 9, pinky finger on the C string at fret 11, middle finger on the E string at fret 9 and ring finger on the A string at fret 10.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 9 | 1 | E (♭3) |
| 3 (C) | 11 | 4 | B (♭7) |
| 2 (E) | 9 | 2 | C♯ (1) |
| 1 (A) | 10 | 3 | G (♭5) |
C♯ minor 7th flat 5th is played in open position as 0 4 7 4: index finger on the C string at fret 4, ring finger on the E string at fret 7 and middle finger on the A string at fret 4. The G string rings open.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | open | — | G (♭5) |
| 3 (C) | 4 | 1 | E (♭3) |
| 2 (E) | 7 | 3 | B (♭7) |
| 1 (A) | 4 | 2 | C♯ (1) |
C♯ minor 7th flat 5th appears as C♯m7♭5 or C♯, and the ASCII form is C#m7b5. It is also spelled D♭ in enharmonic notation for the same sounding root.
C♯m7♭5 adds a minor 7th (B) to the diminished triad C♯–E–G. C♯ diminished is just the triad, so it lacks the B.
The open G and E strings ring against the fretted C♯ and B. Creating a close voicing with the diminished 5th between C♯ and G in the low register.
Yes, but it adds tension because of the ♭5. It works when you want a more dissonant, jazzy color instead of the plain minor sound.