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Level crossings: Nishinakayama-cho Strip House, Aichi, Japan, by Kochi Architect's Studio

AR House commended: Kochi Architect’s Studio deploys a play of intersecting planes to achieve an adept balance of open space and privacy

It doesn’t take long for the Japanese architect Kazuyasu Kochi to sum up the essence of the house inside which he is sipping tea at the kitchen table: on a piece of paper, he simply draws three straight lines marked X, Y and Z, crossing in the middle to form a star-like shape. ‘Usually house grids are covered by walls and floors to make a divided space, which makes everything smaller and closed in’, he explains. ‘But I wanted to connect each space three-dimensionally, using this XYZ grid. This means more room, more light – and also more fun. Space and humans can co-exist with a sense of freedom.’

Welcome to Strip House. The wooden family dwelling – in the rural town of Nishinakayama-cho, not far from Toyota City in Aichi prefecture, central Japan – is a textbook prototype of Kochi’s experimental XYZ concept. Inside, conventional residential notions of closed rooms with walls, floors and doors are nowhere to be seen. Instead, a crisscrossing expanse of vertical and horizontal strips of wood take centre stage, creating a series of staggered platforms throughout.

‘The interior reveals itself as a wooden jigsaw puzzle – and it takes a moment for the mind to unravel its structure, with its unfamiliar angles and irregular, exposed spaces’

It was while watching his own daughter playing in the local park in Tokyo, swinging her way through a jungle gym climbing frame, that the idea came to Kochi that a similar grid could be applied to a house. ‘The jungle gym is similar in concept to an XYZ grid’, says Kochi, who runs Tokyobased Kochi Architect’s Studio, ‘even though you can’t normally live in a jungle gym.’ He was also inspired by the timber frames of wooden houses, adding ‘when a house frame is built, before the walls and floors are put in, it is very beautiful – but when it becomes a “human space” and walls and floors are put in, it becomes very closed’. The goal was to balance what he calls ‘space of structure’ with ‘space of humans’ – resulting in a three-dimensional grid structure that is not concealed, but is, instead, revealed in all its pared-back beauty.

A simple facade of concrete panels offers little clue of the structural complexities that lie within – although it does hint at Kochi’s preoccupation with purity of form and function over visual aesthetics. On slipping off shoes at the entrance, the interior reveals itself as a wooden jigsaw puzzle – and it takes a moment for the mind to unravel its structure, with its unfamiliar angles and seemingly irregular, exposed spaces.

Inside, there are 24 key vertical and horizontal ‘strips’ of larch plywood of various lengths, interconnected using mainly hidden internal connectors and stretching expansively from fl oor to ceiling and outer wall to outer wall. From these span staggered vertical levels, linked by metalframe staircases or wooden ladder-like steps. A visit to the house is not for the faint-hearted, those who dislike heights, or the unfit: it involves lots of stepping up and down, from top to bottom. After entering, a step leads up to a platform where a piano sits beneath a full-height ceiling (complete with chandelier); from here, a metal staircase rises to a central platform, with a cosy seating area and a low table to one side (the owner’s young son loves to play here).

Screen shot 2019 06 13 at 09.42.48 lz

Screen shot 2019 06 13 at 09.42.48 lz

Two further staircases of differing heights lead off on each side to the two bedrooms – from which there are further hidden areas to explore. One bedroom has a stepladder up to a small triangular nook high up near the ceiling with a bookcase and a chair (where the owner likes to read); the corner of the other bedroom features a stepladder down to another cosy (and seemingly fl oating) triangular platform with a round pebble-like cushion and views out of the window.

Back downstairs by the piano, another stair leads down to the kitchen, featuring neatly compact units and a wooden kitchen table; hidden just around the corner is a space with a sofa and TV, which leads to a small bathroom and toilet – and, even here, although the spaces are private and enclosed, the same open feel of the rest of the house is retained with a border of clear windows at the top of the walls. Despite the absence of a traditional domestic structural axis, the end result is exploratory, innovative, bright and beautiful, with an unusual balance between a sense of expansive open space and privacy in its many nooks and corners. Toilet and bathroom aside, there is just one totally ‘closed’ room with conventional walls, ceilings, floors and a door: a tiny guest room tucked away near the entrance.

Kochi architect's studio drawing

Kochi architect’s studio drawing

Click to download

The house was constructed over seven months in 2018 for the architect’s brother Masao Kochi and sister-in-law Ayuka – both teachers – along with their seven-yearold son Sotaro. ‘My brother asked for walls’, adds Kochi with a laugh. ‘So I made this one room for him – and then left the rest of the house open.’

Despite the complexity of the design, Kochi’s ultimate goal was simple: to create a ‘pleasant’ life for its residents. The interior certainly has a strong sense of natural warmth, with countless organic patterns and grains of juxtaposed pieces of wood in gradated shades of brown and orange alongside signs of family life (a school satchel hanging from a hook, a guitar propped against a wall, notices and photos pinned to a board). The quality of light is also striking: tall vertical panels of windows stretch 8 metres in height from the base to the apex of the building, plus a crucial skylight enables sunlight to filter freely throughout the spatial voids that would usually be covered by walls and floors.

Floorplan

Floorplan

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Another unique consequence of the XYZ concept is the refreshingly long lines of vision, not usually found in domestic dwellings – both the top ceiling and the floor of the entire structure can be seen from pretty much anywhere in the house, reflecting how open it is). And even when no one can be seen from the kitchen table, the air is filled with a constant cacophony of domestic sounds – music floating from a distant corner, the regular foot thumps of two young schoolboys leaping around, the chattering of their mothers as they sip tea at a low table upstairs.

This careful balance between open spaces and privacy is particularly innovative: despite the obviously deconstructed physical format and the free-flowing expanses of light and space, its clever and thoughtful design means there are a surprising number of private, peaceful spots to which family members can retreat. Densely populated Japan is synonymous with tightly packed homes and limited space – and, although the long-standing tradition of different generations living together under one roof has faded rapidly over recent decades, many young families today still choose to sleep in one room together, whereas sleeping arrangements are perhaps more private in Western cities.

Site plan

Site plan

Click to download

Ayuka explains that the only request when commissioning Kochi to build the family house was for it to be sukkuri – a Japanese word that loosely translates as clear, neat, simple. (Kochi laughs at this, adding: ‘There’s nothing really simple about this space.’) Ayuka explained: ‘I liked the idea of a simple place where I could hide everything away. But my first reaction when I saw the plans? I did not understand. I was confused. Having said that, now I am living here I am very, very happy. My son loves playing here and my husband has a quiet space where he can go and read.’ The concept works for the family but is clearly not a one-size-fits-all design: the numerous steps, staircases and ladders between levels makes it heaven for young children but would likely be unsuitable for the elderly.

The family living there feel happy as well as stimulated and inspired by their home. The most insightful perspective of what it is like to live in such a space can perhaps be found via its youngest resident, seven-yearold Sotaro. Pausing briefly from a game of firing at targets while leaping between staircases with his friend, he explains that when he first entered the building during the construction period, he found all the open spaces ‘scary’. But he says that changed after moving in – and now it’s ‘the best house for playing hide and seek’. And it’s perhaps also the closest thing possible to living – in comfort – inside a jungle gym.

Architect Kochi Architect’s Studio
Photographs Kazuyasu Kochi

This piece is featured in the AR July/August issue on AR House + Social housing – click here to purchase your copy today