When Masahiro and Mao Harada of Mount Fuji Architects Studio designed this tiny Tokyo home, they decided to cover the interior surfaces with oak boards hammered one-by-one into a honey-colored herringbone pattern. "Using a different material for the wall versus the ceiling versus the floor has become a symbol that signifies a typical ‘house,’" says Masahiro. "I wanted to get away from that and create something more like a cave. I thought that would free up the residents’ approach to how they proactively use the space." The resulting effect is elegant and warm—and a perfect foil to the home’s steely gray staircase.