C# maj7/F#
The C# maj7 chord consists of the C# (Perfect unison), F (Major third), G# (Perfect fifth) and C (Major seventh) notes, with F# as the bass note.

How to play the C# maj7/F# chord
- Play F# as the lowest bass note in the left hand
- Find C# (Root) on the piano keyboard
- Add F (Major third) — 4 semitones above C#
- Add G# (Perfect fifth) — 7 semitones above C#
- Add C (Major seventh) — 11 semitones above C#
- Press all 5 notes simultaneously to sound the C# maj7/F# chord