[jayknight]

Irving Berlin couldn't read music and could only play the piano in F-sharp, so he had a piano build that could transpose to any key[1] and had someone to transcribe his music for him for publication.

[1] https://youtu.be/bO8VZoRw214

[thorin]

Why F#? When I play blues on the piano I tend to play in C (first one I learnt) or Eb. I've noticed Stevie Wonder plays in Eb a lot presumably because he can more easily identify the black notes by feel and Eb blues is mainly black keys.