While the older Main Building functions primarily as exhibition space, the newer Annex serves as a library and archive for the works of the writer Ryotaro Shiba. It also consists of intersecting geometrical forms which are set up on axis to the Main Building; a planar concrete wall two stories high penetrates a rectangular glass volume at an angle to it. Inscribed within the glass volume, at a forty-five degree angle to it, is a concrete cube whose interior perimeter is lined with a stairway.