The entrance of the old building.
The old building (廃墟 haikyo) is only available in Version 6.23 and can be accessed right after clearing the annex basement. To access it however, you will have to find the door hidden in a wall by using the plate shard. It is also the last place you visit before you escape the mansion once and for all. The walls of the Old Building are dusty.
WARNING: This page may contain spoilers or solutions to puzzles. Read further at your own risk!
Puzzles
There are three puzzles in the old building, the die puzzle, the shapes and the the blue pieces puzzle.
The die puzzle in its solved state.
The Die Puzzle
To solve the die puzzle, you'll have to find the missing piece of the die which can be found in the room on the second floor of the old building. Then go to the die room (サイコロ部屋 saikoro heya) and insert the die on the frame to display a series of images. Next, the player must head to the chapel (教会 kyōkai) and follow the designated order of buttons to push indicated by the die frame.
The Shapes Puzzle
The shape puzzle.
Once you open all the bed room (ベッド部屋 beddo heya) curtains you will see shapes in a order of Triangle, Circle, Square and Pentagon. Count all the sides of the shapes. The sides of the shapes will form a 4-digit code if put side-by-side in order of appearance on the curtains, which will open a safe in the Office.
The Blue Pieces Puzzle
The panel with a blue piece inserted.
The blue pieces puzzle is fairly easy to solve. To solve it, you have to
search the old building for the three blue pieces, each of them scattered in places you don't usually expect them to be.
The first one is located in the room where the Oni breaks the floor is where you find the first blue piece, you must first however head to the study and use your screwdriver to unscrew some bolts, making the picture on the other side pop off and leaving the blue piece behind.
If you head to the basement of the old building (廃墟地階 haikyo chikai) and head to the bed room (ベッド部屋 beddo heya) with curtains in it, you will find a rope ladder on top of a bed. Then you will have to go upstairs, put the ladder on where there's a hole and climb down to obtain the second blue piece, this can be done in no order though.
The last blue piece is found in the Oni room. The player must approach the door and suddenly the Hunchback Oni will open the door and start chasing the player, followed by Blockman. After escaping the room, the player can return and find the room empty. From this point on, the player can simply walk and take the blue piece so it can be inserted into the puzzle.
Escaping The Mansion
After you inserted the two blue pieces from the library and the frame, head back to the basement to go to the Oni room which is located on the southwest door. Heading down to the door, you will open it with the basement key you retrieved in the study, you will see a large amount of unusual Onis.
Heading closer to the cage door will cause the Hunchback Oni to the cage to open the door and head toward you. Run back to the door and keep trying to enter until it opens. Then head back into the room and you can get the last puzzle piece, Takuro will appear and ask you if he can join your party. Now insert the piece from the Oni room, you will not be able enter the items menu because Takuro has turned into an Oni. After you lose him, insert the blue piece and the door on the other side of the room will open. Now you are able to escape the mansion once and for all. Once you get close to the stairs, Takuro will appear and chase you in an endless chase if you decide to head back into the mansion.