G# addb9/B#
The G# addb9 chord consists of the G# (Perfect unison), B# (Major third), D# (Perfect fifth) and A (Minor ninth) notes, with B# as the bass note.

How to play the G# addb9/B# chord
- Play B# 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 A (Minor ninth) — 13 semitones above G#
- Press all 5 notes simultaneously to sound the G# addb9/B# chord