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‘Reinvigorating the fading holiday culture of Lake Chuzenji’: On the Water by Nikken Sekkei

AR House 2016 finalist: drawing on traditional teahouse entry paths, the progression to and through this house evokes a sense of ritual

A couple of hours north of Tokyo lies Lake Chuzenji, a pristine and placid body of water rimmed by mountains. From the town of Chugushi on the lake’s eastern edge, a narrow shoreline road leads to the eighth-century Chuzenji Buddhist temple. Discreetly along the way is On the Water, an intricately crafted guest house by major Japanese firm Nikken Sekkei.

The house was an unusual commission for Nikken Sekkei, known for skyscrapers and stadiums. The project was led by Tomohiko Yamanashi, who oversees a 150-person design team and heads Nikken Sekkei’s 40-person technology division. Given the demands on his time, Yamanashi can only take on one such bespoke project each year.

The organising principle of the house is ceremony. The client, an executive at a Tokyo-based multinational corporation, entertains business partners at the house, and the architecture helps to choreograph the guest’s experience. Yamanashi adopted a linear scheme to control what the visitor experiences, and in what order, but twisted the plan into a spiral to lengthen the route through the building. He explained the ‘entrance ceremony’ he designed while taking me through the house.

‘For most buildings, the entry facade is the most important opportunity for public engagement, but On the Water seems hardly to notice the street’

Arriving from Tokyo, usually around 5pm, the client and his guest park behind an entry wall of black stained pine and concrete. An elongated slope leads downward, the house’s cantilevered roof plane superimposed over the landscape beyond. On reaching the entry plane, the guest turns and finds a covered exterior corridor, adding to the sense of procession that Yamanashi borrowed from teahouse entry paths. Before entering, the client and guest often sit on a long concrete bench and have refreshments in the manner of koshikake, waiting spaces that precede entry into a teahouse. The wall and low eaves in front frame the lake and mountain ridge into an extremely horizontal composition.

On entering the house and passing through a foyer, the party arrives in the dining room. Though there is a small kitchen behind a moving wall, Yamanashi explains that the meal is often brought from a nearby hotel. From the dining table, the guests can view the sunset across the lake through a 10m-wide pane of glass. After dinner, they go down to a bar and sitting room that opens onto a wooden terrace, again looking to the lake. The concrete slabs below are covered with local stones, blurring the base of the house with the rocky shore. From a standing position, the mountaintops are cropped, but this view is meant to be seen from the floor. Several zabuton (floor cushions) are collected near the back wall, and the architect tosses them around the expansive room and suggests lounging wherever comfortable.


The rear wall of the sitting room was coated with an aluminium spray and roughly sanded. ‘It’s like ginbyobu,’ says Yamanashi: gilded folding screens enhancing candlelight. ‘It’s the one piece of ornament in the house.’ The aluminium wall catches reflections from the lake and, in the evening, flickers from the light of the fireplace connected to the bar where evenings conclude. From the sitting room, two corridors stretch toward the lake, each leading to a bedroom. The rooms share the same organisation, which begins at a concrete slab by the water and rises in a series of wooden steps and platforms to beds. The steps have zabuton, and Yamanashi again suggests that you find where you’re comfortable rather than using furniture.

While sitting on the zabuton, the view is expansive, but the glass rises from the floor only to around chest height. As you move up the steps, the view angle limits what can be seen, and in the bed area, only an abstracted patch of rock and water is visible: a clever privacy measure. The bed platforms can be closed off to noise and light using sliding paper shoji panels, but Yamanashi hopes the rooms will be kept open, relying on the corridors to separate them from other spaces. This lack of clear separation between interior functions is a major concept for Yamanashi, which he calls ‘continuity of space’. Wherever possible, doors were eliminated or hidden as a last resort. Hand in hand with ‘continuity’, explains Yamanashi, is ‘heterogeneity’, his idea that, because spaces are not defined, you never experience just one space or condition at a time.

‘On the Water has made the rounds online and in print, and has drawn attention to the fading holiday culture of Lake Chuzenji’

Airflow is a component of this continuity, and funnelling the breeze from the lake through the space was a constant concern in the design process. Building Information Modelling (BIM) was used to calculate and adjust to prevailing winds. Cool air from the lake is caught by the long eaves on the upper floor and funnelled through the entry and dining areas. Wind hatches below perform the same function for the bedrooms. The sitting-room area, recessed from the water’s edge, receives less wind, and Yamanashi underlined this difference by adding a fireplace there. ‘There are warm areas, there are cool areas,’ he says. ‘My hope is that people will find where they are comfortable, like a cat.’ Being ‘cat like’, Yamanashi says, ‘is a very important concept in this building’.

Nikken Sekkei used BIM extensively in On the Water, beginning by inputting the landscape including distant mountains into the model. As the spaces began to take shape, the model was used to check views and confirm eaves heights in an effort to crop and frame vistas. This precision is visible when sitting in the outdoor waiting space, as the mountain peaks come just short of grazing the eaves line. Yamanashi says he ‘was amazed at the accuracy of the BIM model’.

BIM was also applied for structural analysis, resulting in a precambered steel roof structure which connects to the slab below using tensile rods. The slab and roof are mutually supportive, and withstand the metre-deep snow loads in winter. Temperatures are extreme enough that On the Water is closed from October to May. The harsh climate provided opportunities though; construction began in winter, taking advantage of low water levels to reduce impacts on the lakeshore.

The impact of the building in its context is more complex, but was on the client’s mind from the inception. ‘Nikko used to be one of Japan’s leading summer resorts,’ the client explains. The lake began as a holiday destination when the British Embassy built a villa there in 1896. By the 1920s, Belgium, Italy and France joined the ranks, paving the way for hotels and ryokan (traditional inns).

‘In recent years, various circumstances have weakened Nikko’s presence,’ the client says. ‘I, however, have always felt that it has high potential.’ The circumstances he refers to came about after the deflation of Japan’s economic bubble in the ’80s caused Lake Chuzenji and similar resorts across the country to lose visitors. The lake’s reputation fell further after the 3/11 disaster in nearby Fukushima. Traces of radiation were found in the lake and, though the water has returned to normal, the stigma remains. The client sees the project as a way to bring attention back to Nikko. Nikken Sekkei was tasked with designing a house that could achieve this and provide something to the community.

For most buildings, the entry facade is the most important opportunity for public engagement, but On the Water seems hardly to notice the street. The facade is diminutive, a simple wall. This replaced a five-storey building, and Yamanashi is pleased that he restored light and wind to the narrow road. But while the void does re-establish a connection between road and lake, the house doesn’t join in the conversation or meaningfully respond to the shops nearby.

‘Spaces are not defined; you never experience just one space or condition at a time’

The house addresses the lake more than the street, and is unusual among its neighbours for its proximity to the water. The Belgian Embassy villa, directly adjacent, is set back from the shore, with space for trees to shroud the architecture. Conversely, On the Water is easily visible from boats and can even be seen from Chugushi. Yamanashi believes the sightseeing boats that circle the lake have adjusted their course to get a view.

Beyond this, the house’s impact is unclear. The several people in the small town I ask seem only vaguely aware of it. ‘Those are Tokyo people,’ one woman says simply. ‘They don’t come here much.’ Indeed, the client visits Nikko only a few weekends a year.

The economic or social impact of his presence cannot be much even if the vote of confidence the new building represents is significant. On the Water has made the rounds online and in print, and has drawn attention to the fading holiday culture of Lake Chuzenji, but is unlikely to improve anything beyond its walls. 

Architect: Nikken Sekkei - Tomohiko Yamanashi, Satoshi Onda, Hajime Aoyagi

Structural engineer: Toshihiko Kohno, Kaoru Kujime, Takumi Kurokawa

Photographs: Martin Holtkamp

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