The Piano puzzle is a puzzle that is present in Ao Oni versions Version 3 , Version 5 , and Version 6 . As the name implies, the player has to use the numbers written on the piano keys to solve a open a locked safe behind the bookshelf.
To find the number combination, you should use the handkerchief and the soap and wipe the red stain. After the player discovers the number combination written on the piano, they use the keys on the panel to decipher the code. The player has to match the numbers on the keys of the piano to the shapes of the keys on the panel. The orientation of the first and last keys are noteworthy because they are the only two keys that are upside down, so the numbers that correspond to the panels must also be flipped. Once the combination is known, the player can input it to solve the puzzle.