The tune Kaori plays in the scene where Kousei first meets her is "Morning in the Slag Ravine" (from Castle in the Sky (1986)) by Joe Hisaishi.
All of the pieces played are well known classic pieces, played by real pianist specifically for the show
Most songs played were by the famous pianist Frederic Chopin.
The black cat is a symbol of Kousei and the dove is a symbol of Kaori
The second collaboration with Erica Mendez and Rachael Lillis after Hunter x Hunter (2011).