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. The Oni chases Hiroshi right after finishing this puzzle.
Hiroshi in the piano room.
Variations
Version 3.0
The numbers are always 459 and the answer is 6495.
Version 5.2
The numbers are random, with 10 possible answers.
Version 6.23
The numbers are random, with 5 possible answers.
The Solution
To find the number combination, you should use the handkerchief and the soap and wipe the red stain (probably blood). After the player discovers the number combination written on the piano, they must then find a note depicting four keys, the location of which differs depending on the version, then decipher the code in the safe (behind a bookshelf). In Version 5.2, a memo is found in the bedroom above the piano room with two keys on it. The player must use the lighter to heat the memo to reveal two hidden keys. In Version 6.23, the keys are directly on the safe itself. The player has to match the numbers on the keys of the piano to the shapes of the keys on the note.
The panel with the piano keys.
The orientation of some keys are noteworthy because they are being rotated, so the numbers that correspond to the panels must also be rotated ( e.g. 6 -> 9 ). Once the combination is known, the player can input it to solve the puzzle.
In Version 5.2, there are 10 possible number configurations, and in Version 6.23, there are only 5. In Version 6.23, you always need to enter in the order of 3rd number rotated, 2nd number, 3rd number and 1st number rotated to solve this puzzle. In Version 5.2, that order is also possible, but there is another order that can occur randomly: you must instead enter in the order of 1st number, 3rd number rotated, 2nd number, and 1st number rotated.
In the list below, the code on the left is possible in both Version 5.2 and Version 6.23, and the code on the right is possible in Version 5.2 only.
Number: 176 - Codes: 9761, 1971
Number: 239 - Codes: 6392, 2632
Number: 941 - Codes: 1416, 9146
Number: 679 - Codes: 6799, 6679
Number: 915 - Codes: 5156, 9516