The Ushiromiya Main Building (右代宮家 本館 Ushiromiyake Honkan ) is the mansion on Rokkenjima where Kinzo and Krauss' family resides, completed sometime in 1952. It is where most of the murders take place in Umineko no Naku Koro ni.
Before the Guest House was built between the years 1983–1984 the guests were accommodated in the mansion's guest rooms.
The mansion has three stories and a basement.
It is the lobby of the mansion where the Portrait of Beatrice with the witch's epitaph is located which was put up in April 1983. Since Battler has no memories about it he is be informed or questions about it. The stairs in this room lead to the second floor. The main door can locked with a key. At the time the conference occurs the door is usually locked.
It's the place where the family eat together. The seat order depends on the ranking of the family member
(family head - children of the family head - their children - their spouses - family head's wife).
After dinner Maria take out a letter she got from Beatrice and read it out.
Guests from the outside and the family's doctor Nanjo are allowed to sit and eat with the family together.
The servants come to break here. It holds most keys of the mansion in a box. In the story wounded persons will be brought here.
A relaxing room where usually the surviving characters gather after the first twilight victims were discovered. It has its own key and can be locked and opened with a master key. The double door can be blocked with a long thing like candle holder.
This floor comprises the rooms of Krauss' family and the guest rooms which are linked with corridors.
Natsuhi's sleeping room she doesn't share with her spouse, Krauss. It has a dressing desk which holds her personal items like the spirit mirror. This room can be locked by a chain lock, the room's key and any master key.
Krauss' working and sleep place. It can be locked like most rooms in the mansion with a master key and chain lock, but it's unknown whether the room has it's own key.
These rooms were be used by the arriving family members before the Guest House was completed. Therefore, they are going unused most of the time unless they are used for a crime. Each guest room has two beds, a closet, a bathroom, a phone and a chain lock. The guest rooms have their own keys and the master keys work on them.
Kinzo's personal room where he spent most of the time researching occult and magic to revive Beatrice, isolated. Natsuhi, Krauss, Nanjo and the servants but Gohda occasionally enter it. The adults, especially Eva, try to talk to Kinzo. It is described as a 'small villa' by Battler in EP 5. It's divided into multiple rooms: a study, a book archive, a sleeping place and a bathroom. The study holds a smaller copy of the portrait in the lobby.
The study has a autolock system that closes it after opened. It has 2 keys which one Natsuhi possess and the other is in Genji's hand. The door is protected by a scorpion charm which don't allow evil spirit's to enter.
The survivors goes there to examine orign of the strange smell that comes from the boiler room. Kinzo's burned body is always found here. There are two ways to enter it: a door from the first floor or the inner courtyard. The key to this room and any master key can lock and open them.