Structure of the Building
The original building was constructed facing the Motoyasu-gawa River to the west. In the center was a courtyard with an open ceiling, and an oval-shaped spiral staircase.
The building was three floors high and had multiple windows, with the central staircase area five stories high, capped by a dome on top. A partial basement was included.
The building was constructed of brick with a partial steel frame reinforcement. The exterior was made of mortar and stone, and a major part of the inner walls was coated with plaster.

(Photo: Hiroshima Peace Memorial Museum, donated by Hitoshi Usui)
Dome

Spiral staircase

Stairs to the basement
On the east side of the spiral staircase, stairs connecting to the basement remain. The hollow on the lower left side of the stairs in the picture on the right is the basement.
Plaster coating
Remains of plaster coating can be seen, especially on the south and north walls of the dome. The picture on the left shows the layers of plaster base coating, limewash middle coating, and plaster top coating. The letters in the picture on the right are graffiti made sometime between the time of the bombing and the Dome’s preservation.
Holes for the beams
Holes for the beams remain on the wall surface. Their location allows one to estimate the position of the burnt-down beams and the height of each story.