G dim7/Ab
The G dim7 chord consists of the G (Perfect unison), Bb (Minor third), Db (Diminished fifth) and Fb (Major sixth) notes, with Ab as the bass note.

How to play the G dim7/Ab chord
- Play Ab as the lowest bass note in the left hand
- Find G (Root) on the piano keyboard
- Add Bb (Minor third) — 3 semitones above G
- Add Db (Diminished fifth) — 6 semitones above G
- Add Fb (Major sixth) — 9 semitones above G
- Press all 5 notes simultaneously to sound the G dim7/Ab chord