Plan 21 Splits a Toyama Two-Family House into Linked Volumes Around a Shared Courtyard Garden

Living with extended family doesn't have to mean compromising on privacy or independence. The Machikado Project in Toyama by Plan 21 proves this with a deceptively simple move: split the program into two separate buildings, one single-story for the mother, one two-story for the son and his wife, then knit them together with a courtyard garden that belongs to everyone. From the street, the dark timber volumes read as a single composed residence. Up close, the gaps between them reveal something more generous.

The project is part of Plan 21's broader Machikado series, an ongoing effort to improve residential environments by thinking beyond the boundaries of a single house. Rather than designing one building as an isolated object, the practice designs clusters and relationships between structures, treating the spaces between walls as carefully as the rooms within them. At 159 square meters total, the Toyama house is compact, but it lives larger than its footprint thanks to a layered sequence of covered terraces, planted courtyards, and timber decks that dissolve the line between interior and landscape.

A Street Presence Built from Charred Timber and Garden

The street facade is quiet but deliberate. Dark charred timber cladding wraps both volumes, giving the house a cohesive material identity that absorbs light rather than reflecting it. Metal standing seam roofs tilt at gentle angles, and a carport with a vegetable trellis anchors one end. Terraced stone steps climb through planted beds to the entrance, making the approach feel more like entering a garden than a building. The result is a house that contributes to its neighborhood rather than withdrawing behind a wall, which is the core thesis of the Machikado series.

The planted concrete curbs along the street edge and the field of tall grasses in front soften the boundary between public sidewalk and private ground. A bicycle leans against the facade at dusk, stacked firewood screens the entry path, and the whole scene feels cultivated rather than constructed. Plan 21 has clearly thought about what this house gives back to the street.

Twilight Reveals the Logic

Photographed at dusk, the house reveals its organizational logic most clearly. Interior light spills through glazed openings, illuminating the gaps between volumes and showing how each building relates to its neighbor. The planted beds, the stacked firewood wall, the bicycle propped against dark timber: these elements compose a scene of everyday domestic life that feels considered without being precious. The tall grasses in the foreground blur the foreground and create a soft veil between the viewer and the house, reinforcing the idea that the boundary between public and private here is graduated rather than abrupt.

The Courtyard as Connective Tissue

The central courtyard is the most important room in the house, even though it has no roof. Glass walls on both sides allow each family unit to look across at the other through a filter of tropical plantings, moss-covered stone pavers, and stepping stones. The space mediates between the two generations: close enough for daily contact, buffered enough for genuine privacy. A covered terrace with slender timber columns runs along one edge, providing a shaded threshold where residents can sit outside without being exposed to weather or the street.

What makes this courtyard more than a light well is the density of its planting and the quality of its ground plane. Moss, stone, and gravel create a miniature landscape that changes with the seasons, and the enclosing charred timber walls give it a sense of containment without claustrophobia. It is a shared amenity that neither family owns exclusively, and that generosity is what makes the multi-generational arrangement work.

Timber Decks and Screened Terraces

Each volume extends outward through timber deck terraces screened by horizontal wood slats. These screens do double duty: they provide privacy from neighbors while filtering light into patterns that shift through the day. At dusk, the decks glow as interior light passes through the slats and reflects off the polished concrete and timber surfaces. Sliding glass doors along the full width of the living spaces erase the wall between inside and out, allowing the terraces to function as extensions of the main rooms during Toyama's warmer months.

The vertical planted wall along one covered terrace edge adds a layer of greenery that softens the hard geometry. Plan 21 treats these transitional spaces with the same care as the finished interiors, providing polished concrete floors, carefully detailed timber ceilings, and flush thresholds that make stepping outside feel like moving into an adjacent room rather than leaving the house.

Timber Interiors and the Warmth of Wood

Inside, exposed timber ceilings and wood-paneled walls establish a warm, consistent material palette. The living and dining spaces are open and generous, with horizontal slatted shutters that can be adjusted to control light and views. A pendant light hangs over the dining area, which is framed by shoji screens, introducing a traditional Japanese spatial device into an otherwise contemporary plan. The flush threshold between living room and outdoor deck is a small detail with an outsized effect: it makes the garden feel continuous with the floor, pulling nature into the domestic routine.

A wood stove sits near the courtyard-facing windows, framing a view of the garden through timber-framed glass. The choice of a wood stove is practical in Toyama's cold, snowy winters, but it also connects to the stacked firewood visible throughout the project. Fuel becomes decoration, storage becomes screening, and function becomes atmosphere.

Views Through and Between

Plan 21 has composed the interior views with precision. From almost any position inside the house, the eye is drawn through a sequence of frames: timber mullions, sliding glass, courtyard planting, the opposite building's facade. The depth of field in these views is what makes a 159-square-meter house feel expansive. You are never looking at a wall; you are always looking through something toward something else. The courtyard garden functions as a visual extension of every room it touches.

The charred timber wall of the opposing volume, seen through sliding glass doors, acts as a dark backdrop that makes the courtyard greenery pop. Horizontal screens layer additional texture into the middle ground. These are carefully staged perspectives, but they don't feel theatrical. They feel like what happens when an architect pays close attention to how people actually look at things while sitting in a chair, standing at a counter, or lying in bed.

Firewood, Grasses, and Dusk

Several of the strongest images of this project are atmospheric rather than architectural. The stacked firewood wall beside a concrete walkway, lit from within by the warm glow of the courtyard garden at dusk. The linked volumes seen behind a field of tall grasses under blue sky. The timber deck terrace at twilight, with illuminated interiors beyond. These images capture something essential about the Machikado approach: the house is not just a shelter but a piece of landscape, a composition of materials and plantings that has a presence at every hour of the day.

Plans and Drawings

The watercolor-rendered site plan and axonometric drawing reveal the project's organizational clarity. Two houses, each with its own roof geometry, are separated by open courtyard spaces and connected by circulation paths. The annotated landscape features in the site plan show how deliberately each planting zone has been considered, from the street-facing grasses to the courtyard garden's stepping stones. The cross-section is equally telling: two sloped-roof volumes stand apart, framing a void between them that is as shaped and purposeful as any room.

The axonometric drawing is particularly revealing. It shows how the covered terraces, decks, and screens create a layered sequence of spaces that graduate from fully enclosed to fully open. Interior rooms, glazed walls, covered terraces, timber decks, planted courtyards, and finally the street. Each step in the sequence shifts the balance between shelter and exposure, privacy and community. It is a simple diagram executed with material richness.

Why This Project Matters

Japan's aging population and shrinking household sizes make multi-generational living an increasingly relevant typology, but few architects handle it with this degree of spatial intelligence. Plan 21's Machikado Project doesn't just put two families under one roof. It gives each family its own building and then invests all of its design energy into the spaces between them. The courtyard, the terraces, the screened decks: these are the places where the two households overlap, and they are the best rooms in the project. That inversion of priority, making the in-between more important than the enclosed, is what makes the scheme genuinely inventive.

The broader Machikado series deserves attention beyond this single project. By designing houses as groups rather than objects, Plan 21 is engaging with the texture of the Japanese residential neighborhood at a scale that most practices ignore. The result in Toyama is a house that reads as part of its street, contributes greenery and character to its block, and accommodates two generations without asking either to sacrifice independence. At 159 square meters, it is proof that generosity in architecture has very little to do with size.

Machikado Project in Toyama by Plan 21. Toyama, Japan. 159 m². Completed 2026. Photography by Akira Ueda.

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