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

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