How do you open the safe in crisis core?

Answer 1

Already been answered

First Digit: Go to the room on the east side of the second floor and look through the keyhole. The first digit is the number of books that are not on any shelves in the bookcase. Don't forget to count the ones on top of the bookcase!

Second Digit: Go to the room on the east side of the first floor, look through the keyhole, and count the number of Dorky Faces inside. They will sometimes disappear, but will always remain in the same place.

Third Digit: Go to the room on the west side of the second floor, look through the keyhole, and count the number of Banora apples and/or cans in the room. Be sure to check under the furniture or on the floor.

Fourth Digit: Go to the room on the west side of the first floor, look through the keyhole, and count the number of chairs in the room.

Use the four digits to open the safe and receive the Vital Slash materia.