Seienkaku Residence’s Secret Architectural Details: Kugikakushi (nail ornaments)

Kugikakushi are decorative ornaments used in Japanese architecture to conceal the heads of large nails driven into long posts or doors. They were made in a wide variety of materials, shapes and designs, including wood, copper, iron, gilt bronze, and ceramics; some also feature cloisonne, inlay and openwork techniques. Various kugikakushi can be seen on the ground floor of the Seienkaku residence, which was built during the Edo period. 
In particular, on the first floor one can see examples of rindōguruma (five gentian flowers and leaves in the shape of an annulet or wheel) kugikakushi which feature the Homma family crest; they are also used in the Homma family’s main residence. Other kugikakushi can be seen throughout the rooms of the Seienkaku residence, featuring hollyhock designs and cloisonne decoration.