"Ichiin" is a house that transforms the constraints of the site, namely a 5m difference in elevation and a triangular shape, into a space that coexists with the environment. Layers of iron mesh manipulate the line of sight and sense of distance, creating openness, depth, and tranquility in the exterior fill. Time is one of the design keywords, and the house exudes a sense of extraordinary quality and antique beauty while demonstrating sustainable durability. It harmonizes urban density with social interaction, and privacy with openness, presenting a glimpse of a new form of Japanese design.