D b5/F
The D b5 chord consists of the D (Perfect unison), F# (Major third) and G# (Diminished fifth) notes, with F as the bass note.

How to play the D b5/F chord
- Play F as the lowest bass note in the left hand
- Find D (Root) on the piano keyboard
- Add F# (Major third) — 4 semitones above D
- Add G# (Diminished fifth) — 6 semitones above D
- Press all 4 notes simultaneously to sound the D b5/F chord