C# b5
The C# b5 chord consists of the C# (Perfect unison), F (Major third) and G (Diminished fifth) notes.

How to play the C# b5 chord
- Find C# (Root) on the piano keyboard
- Add F (Major third) — 4 semitones above C#
- Add G (Diminished fifth) — 6 semitones above C#
- Press all 3 notes simultaneously to sound the C# b5 chord