Gb maj7/Bbb
The Gb maj7 chord consists of the Gb (Perfect unison), Bb (Major third), Db (Perfect fifth) and F (Major seventh) notes, with Bbb as the bass note.

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