A# 6/C#
The A# 6 chord consists of the A# (Perfect unison), D (Major third), F (Perfect fifth) and G (Major sixth) notes, with C# as the bass note.

How to play the A# 6/C# chord
- Play C# as the lowest bass note in the left hand
- Find A# (Root) on the piano keyboard
- Add D (Major third) — 4 semitones above A#
- Add F (Perfect fifth) — 7 semitones above A#
- Add G (Major sixth) — 9 semitones above A#
- Press all 5 notes simultaneously to sound the A# 6/C# chord