Project Name: House with a Large Roof

Location: Kitasaku, Nagano, Japan

Design Team: Yaita and Associate Co., Ltd.

Floor Area: 139.71 m²

Year of Completion: 2025

Photography: Ogawa Shigeo

Design Features: Perched on a sun-drenched slope in Kitasaku, Nagano, this family residence by Tokyo-based Yaita and Associate Co., Ltd. demonstrates how a single sweeping roof can transform a hillside into a place of profound spatial richness. Designed for a family relocating to the Karuizawa area, the house occupies a southeast-facing incline pitched at approximately thirty degrees. Rather than resist the gradient, architects Hisaaki Yaita and Naoko Yaita embraced it, draping a generous roof across the slope and orchestrating a layered sequence of interior and exterior space beneath it.

The defining gesture is an L-shaped balcony that wraps around the living room, extending three metres outward on the approach side and folding along the valley edge to frame the primary living space. Floor-to-ceiling retractable glazing — spanning two metres to the south and seven metres toward the valley — dissolves the boundary between inside and out, allowing the living room to merge seamlessly with the balcony and command panoramic views across the forest canopy.

A continuous parapet wall lines the balcony, its low profile concealing the road nine metres below while directing the eye upward through treetops to open sky. The thirty-centimetre-wide coping doubles as a writing surface, a small but considered detail that speaks to the architects’ attention to lived experience.

Structurally, wall beams spanning north to south suspend the cantilevered balcony from the mountain side, while black-painted iron braces support it from below, an honest expression of forces that also defines the interior, gently separating entrance, bookshelves, and kitchen from the principal gathering space. The main volume is governed by strict proportional logic: a double-square footprint and a 3:4 sectional rectangle, embedding the home within a larger geometric order that the architects liken to a resonance between architecture and universal geometry.

Design Team: Founded in Tokyo in 1994 by principal architect Hisaaki Yaita following a formative eleven-year tenure at the distinguished Taniguchi Architectural Design Institute, Yaita and Associate Co., Ltd. has established itself as one of Japan’s most thoughtful practices working at the intersection of landscape, materiality, and the lived experience of domestic space. The firm was reorganised under its current name in 2005, when Naoko Yaita joined as co-principal, bringing with her over two decades of experience at Archibrain Architectural Research Institute under the mentorship of Hiroyuki Wakabayashi.

Operating under the guiding principle of “Architecture as a Landscape,” the practice pursues a design philosophy rooted in environmental integration and enduring spatial quality. For Hisaaki and Naoko Yaita, architecture should deepen rather than diminish with time, cultivating what the firm describes as a sense of “place-ness” that emerges only when the designer’s ego yields entirely to the wellbeing of those who inhabit the space.

The practice’s critical standing is affirmed by an extensive award record, including the German Design Award Winner (2018), the Architecture Master Prize Gold Prize in New York (2016), and the Japan Institute of Architects New Architect Award (2013). Both principals hold the JIA Registered Architect designation and are active members of the Architectural Institute of Japan.