Oyamadai House is a minimal residence located in Tokyo, Japan, designed by frontofficetokyo. With a flag shaped site bound on every side by neighbors, the understandable instinct might be to step away from the city, retreat behind walls where privacy is better assured. The family that purchased the site saw instead a chance to be as open as possible, using the small degree of isolation as a chance to connect to the city from a slight remove. On the ground floor the concrete floor extends out to form the landscape, softened by an abstract for that aims to blur boundaries – not between inside and out, but between city and home. On the second floor terraces and stair landings take on the same task. A wooden structure normally would work against these ambitions, requiring large sheer walls or braces to resist earthquakes. To answer this need without losing the intent to open the spaces we built large X-shaped walls at either end of the house. Like flying buttresses, these work as structure without interfering with the desire for openness.