Tokyo has its own Sagrada Família. And now, they have even moved it

What many call the “Sagrada Família of Tokyo” belongs to that discreet and extraordinary architectural heritage in Japan that continues to challenge the very idea of a building as an immovable object. Keisuke Oka’s Arimaston Building, begun in 2005 and built by hand for over twenty years, was moved in 2025 by about ten meters thanks to the Japanese technique of hikiya, which allows an entire building to be relocated without being demolished. 

This was no simple relocation, but an engineering operation that lifts the structure from its foundations, secures it, and guides it toward a new position, preserving its material, memory, and identity. The neighborhood where it stands is Mita, in the Minato area, a district of Tokyo that roots itself in the Edo Period and today presents itself as an elegant, central, and transforming urban landscape.

Here, residences, institutions, schools, and real estate pressure coexist – a pressure that has reshaped the face of the neighborhood over time. It is precisely this stratification, made of permanence and replacement, that makes Mita the ideal place to understand the fate of the Arimaston: a singular building, born out of craftsmanship and then saved not through nostalgia, but through mobility.

It bears an equally unique name. In kanji, it is 蟻鱒鳶ル, a composition invented by architect Keisuke Oka that combines the characters for ant, trout, and black kite. It is not a common word, but a poetic name, almost ungrammatical by choice, reflecting the nature of the project: an off-catalog architecture, capable of evoking the animal world while evading immediate definitions. The name seems to suggest that the building does not want to be read as a conventional object, but rather as a hybrid creature, balanced between fantasy and actual construction.

Oka began working on it in 2005, armed with essential tools and an idea deliberately free from design rigidities. For nearly twenty years, he shaped, added, corrected, and rewrote his building by hand, making it a sort of three-dimensional construction diary. The architect built the Arimaston by implementing a radical process of total self-construction, which involved manually mixing and transporting raw materials like concrete, step by step, without any heavy machinery. 

Operating without fixed blueprints, he improvised the architecture as it evolved, transforming the entire structure into a sculpture. Throughout this process, he relied strictly on manual tools and a crafted approach, turning the construction site into an ongoing work of performance art. It is a story that captures interest more for its process than for the finished result: irregular surfaces, unexpected curves, oblique openings, and details achieved through an obstinate, almost anti-industrial manual skill. And this is exactly where hikiya enters the scene.

The technique was applied in 2025, when the redevelopment of the area made it necessary to move the building. Instead of tearing it down, the choice was made to preserve it in its entirety and slide it into a new position. The charm of the story also lies in this paradox: the Arimaston Building is radically personal, almost solitary, yet it relies on a collective, ancient, and codified technique born to give buildings a second life. Hikiya does not interrupt its narrative; it extends it. In a neighborhood that constantly tends to rewrite the landscape, the relocation of the building becomes a gentle act of resistance. It preserves not just a volume, but an idea of architecture made of time and patience.

Seen up close, the story of the Arimaston is also a reflection on the possibility of inhabiting the city without fully conforming to its speed. In Tokyo, where modernity often coincides with rapid replacement, this building remains an exception: born slowly, it was built by hand, and even its relocation has become part of its form.

On a late May evening, I walked up the Hijirizaka slope, looking for the building I had read a brief description of. The light was already turning into my favorite kind – golden and lateral – and the Arimaston appeared suddenly: a small, living presence among the skyscrapers, surprising in scale and personality, like an unexpected encounter with something fantastical, a sprite in the middle of the urban forest. Even more interesting was the sight of a man at work, who later turned out to be one of Oka’s collaborators. 

At that moment, he was absorbed on a ladder, balancing on two rungs, installing transparent pipes and plastic gutters held up by ropes. As Oka had mentioned in a previous interview, the idea that he built everything entirely by himself is actually a myth. “My imagination is limited,” he said, “it was thanks to working with others that larger and larger doors gradually opened up.”

It is within this transition that the Arimaston defines itself best: as an open work, grounded in intuition, manual skill, and collaboration. As if its destiny were to keep changing without ever ceasing to be itself.