C# Viennese trichord/B
The C# Viennese trichord chord consists of the C# (Perfect unison), D (Minor second) and G (Diminished fifth) notes, with B as the bass note.

How to play the C# Viennese trichord/B chord
- Play B as the lowest bass note in the left hand
- Find C# (Root) on the piano keyboard
- Add D (Minor second) — 1 semitone above C#
- Add G (Diminished fifth) — 6 semitones above C#
- Press all 4 notes simultaneously to sound the C# Viennese trichord/B chord