Conceptually, the quirky house on an L-shaped lot in the affluent outskirts of Osaka has a lot in common with a traditional Japanese dwelling. Fixed, internal walls are conspicuously absent, furnishings delineate functional zones, and the roof is the defining architectural element. It even has a hanare, or freestanding room separated from the main house. But any likeness between old and new comes to a screeching halt there. Called House K after the first letter of the client's last name, the latest home from Sou Fujimoto'a Tokyo architect known to push residential design to extremes'is a single, swooping volume that emerges gently from the ground and then rapidly surges upward before tapering to a blunt point at the site's east end. Studded with trees in giant steel planters, the sloped wedge of a house looks more like a man-made landform than a place to call home.

While the notion of blending architecture and landscape fascinates Fujimoto, it wasn't exactly what his clients, a couple with two school-age kids, initially had in mind. Though they had few specific requests, their first hope was to create a facsimile of Fujimoto's House N (which appeared in the April 2009 issue). But try as he might, the architect could not fit that building's nesting-box scheme on the 3,340-square-foot property, hemmed in by houses on three sides, open to a grove of trees on the fourth, and tethered to the street by a 98-foot-long path.