IGNITION Staff
The Quest of Keisuke Oka, Creator of the Arimaston Building
by Rumi Tomiya
The Arimaston Building, Created by One Person
The Mita district of Tokyo’s Minato Ward. About 700 meters from Tamachi station as you leave the office buildings behind and continue into a quiet residential area, you come across a conspicuous concrete building sitting on a mere 40 square meters of land. This is the Arimaston building. The architect is Keisuke Oka (49).
At first glance it looks like some kind of strange object, but at root it’s an actual “building” where Oka plans to make his home. Oka is a first-class registered architect, but he is doing much more than just drawing up the plans. He is doing everything involved in the building’s construction, from gathering the materials and putting up the scaffolding to mixing the concrete and putting the building itself together.
Construction began on February 23rd, 2005. But even now, after ten years have passed, the building doesn’t look anywhere near complete. Nonetheless, it has a daily stream of visitors from all over Japan coming to have a look and learn from the process. In response to the building’s peculiar shape, Oka is sometimes called “the Gaudí of Mita.” But why did he start such a project in the first place?
“Building as if Dancing”
Oka was born in 1965 in Fukuoka prefecture. He had dreamed of building houses from the age of 14, but initially had given it up in part due to poor health. After graduating from a nearby technical high school, he began working for a home manufacturer. However, his passion for creating homes unabated, he spent several months each year from the ages of 23 to 28 travelling around Japan by bicycle with a sketchbook to make drawings of architecture. While jotting down works of architecture from across Japan, his own desire to create houses continued to burn.
From 1988 he has participated in the Takayama Architecture School. Architect Yasuo Kurata started this private camp in 1972. For 30 days each summer, students gather in the mountains in Gifu prefecture to study self-building techniques, draw blueprints, and debate ideas.
During the rest of the year, he worked on construction sites doing things like moving earth, building scaffolding, setting reinforced concrete, and doing molding and joint work. He also pursued dance as one part of his activities. He has even been arrested by the police after repeatedly doing performances on the street.
Based on these experiences, his drawings for the Arimaston focused on the idea of “wanting to build improvisationally, like dancing.” In 2003 these drawings were chosen for an architecture exhibition often considered the gateway to success. They won the special jury prize, drawing further attention to the project.
Architecture to Last 200 Years
“Homes today are boring. Buildings, offices, and homes are all drawn on a computer and then built exactly to those plans. They don’t reflect anything that was felt on site,” says Oka, whose Arimaston building has no plan.
Oka, who says “I am more like an old man playing with a bonsai tree than an architect,” continues to improvise while pouring his concrete.
“I think things like ‘it would be good to put a window over there, so you can see people coming down the slope,’ or ‘if there is a window here you could see Tokyo Tower.’ I want to discover things as I am building. By doing so, the building will become more and more alive.”
In order to “build as if dancing,” he departs from ordinary architectural techniques. He uses a method of construction he calls the “70 centimeter method.” Most concrete architecture uses large-scale machines, designed to assemble one floor at a time. However, Oka assembles his concrete by his own hands. To do so, he does 70 centimeters sections one at a time, as that is the width of his reach. As he is pouring the concrete he also does things like mixing it with wood chips, making round holes in it with a plank, and covering the holes with vinyl. These different kinds of poured concrete present a wide variety of expressions. You could say it is a style perfectly suited to Oka’s desire to build “as if dancing.”
There is also a secret to the concrete he uses.
The key is the amount of water mixed in to the concrete. Generally speaking, concrete is made up of gravel and sand. Cement and water are mixed into it to make an adhesive, which then hardens. From the perspective of durability, concrete made of less than 40% water is said to be just right, but concrete with 55 to 60% water is commonly used in construction.
According to Oka, “A high water concrete is easier to use at the construction site.” It washes off easily after the day’s work is through. Because lowering the water content raises the adhesiveness, it is hard to shape cleanly. In contrast, concrete with a high water content can give a smooth and polished look.
However, this results in a big difference in durability. It is said that concrete buildings in Japan have an average life span of 35 years, and may last up to 50 with good maintenance. In contrast, the Arimaston uses the more sticky kind of concrete, which architecture specialists have said will last “200 years.”
The surface of the Arimaston certainly has a coarse and jagged appearance. “Right now it’s too messy. I plan to make it a little cleaner,” laughs Oka.
Are Japanese People Happy?
It is now 2015, 10 years since the start of the project. The final plans call for one basement floor and 4 upper floors, but right now the building only has 3 floors that are partially finished. The project has also been halted for a half-year, as an area including the land used by the project has been designated for redevelopment. However, Oka is not giving up. “I wonder I can’t move somewhere else along with the Arimaston. With contemporary Japanese technology, he says that is a possibility.
“It didn’t feel right building the Arimaston in Mita. It is covered over in offices, so many that if feels like there must be more salarymen here then anywhere else in Japan.”
Oka laughs while saying this, but also describes that as he was building he began to feel the reason for building it in Mita. “Sometimes when I go to the station in the morning, I see many people whose faces make you think they must be on the way to a prison camp. They leave the station and are swallowed up by their companies. On the other hand, when they leave their offices at 5 or 6 in the evening everyone looks so happy. The office women are all fashionably dressed like celebrities, with big smiles. Is this really good for the world?”
“Tamachi is a miniature version of Japan. I think if we don’t improve working conditions, Japan will not improve.”
A Job You Think Is Worth Doing
While the Arimaston has a lot of fans, not everyone is happy with it.
“Nobody is happy with their jobs. So when they see someone nearby who seems to be enjoying their labor, they say ‘its painful to see you working so happily.’” Oka says he has received these kinds of complaints.
“Partly I’m just gloating, showing off how much fun I am having.”
Oka says the Arimaston could not have been pursued 30 years ago. With the development of the internet, it is easy to look up construction methods and material suppliers yourself. You can go buy your own materials at the large home improvement centers. If you ask on Twitter, people you have never met before will come to help you.
“In my hometown, it was fun to see the process of building a home. Nowadays construction sites are enclosed and cut off from their surroundings, and you can’t see anything. For me the process up to completion is also something to be enjoyed. You know, I do want to show it off. Start doing a job you think is worth doing. We’re in an age where you can do that.”
(photo: Daisuke Hayata translation: Paul R. Shimizu)
Originally published at ignition.co.