G m9/G#
The G m9 chord consists of the G (Perfect unison), A# (Minor third), D (Perfect fifth), F (Minor seventh) and A (Major ninth) notes, with G# as the bass note.

How to play the G m9/G# chord
- Play G# as the lowest bass note in the left hand
- Find G (Root) on the piano keyboard
- Add A# (Minor third) — 3 semitones above G
- Add D (Perfect fifth) — 7 semitones above G
- Add F (Minor seventh) — 10 semitones above G
- Add A (Major ninth) — 14 semitones above G
- Press all 6 notes simultaneously to sound the G m9/G# chord