Picture Book Museum, Iwaki City

The building occupies 492.07 m 2 of space, with the total floorspace amounting to 634.05 m² in Ando's building. Decorations are minimal, largely consisting of the books themselves in a cover-out display that dominates the space. The only three materials uses in the building are fair-faced reinforced concrete, glass, and wood. Though some may consider concrete a sterile or bland material, Ando sees it as warm and complex. He states, “Concrete can be very rich in color … the gradations of color create a sense of depth”. The simplicity of color is noted by some reviewers who mention the fact that the Western notion of child-friendly decor is less stark and angular. In the Picture Book Library the only color is supplied by the bright patterns of the books themselves. The corridors are kept deliberately dark, in defiance of a possible Western preference for evenly light-filled spaces. “You will be able to see the light because of the darkness,” says Ando.

A total of 6000 people visited the Picture Book Library in its first 10 months, often 200 on each public day and visitors have exclaimed of the building: “The museum is "architecture of light...the concrete feels so warm". Critics say "a tension-rich rhythm develops out brightly and darkly, from open and closed zones". "Like so many of his greatest buildings, it pulls off a remarkable illusion: the walls may be built from blocks of concrete, but, from the inside at least, the building feels as if its primary materials were light and air". "There is no dead end,” one blogger noted, and they were reminded of M. C. Escher. A group of students raved it "is spectacular, offering views across the Pacific Ocean from anywhere on the premises...This space is fun even for adults".