In Tokyo’s Mita district, a unique concrete building named Arimasuton stands out amid the district’s modern high-rises. Over the past 21 years, architect Keisuke Oka, 61, has personally constructed the four-story structure, which defies Japan’s typical architectural approach that favors short-lived buildings demolished within decades.

Built to endure for more than a century, Arimasuton incorporates a raw, unfinished aesthetic with exposed concrete, oxidized metal, hanging chains, and visible rebar. Its design features asymmetrical windows, irregular doorways, and a sprawling void nearly half the building’s height, crisscrossed by arching beams. The interior walls bear decorative imprints, including grapevine patterns and geometric shapes created by pressing food containers into the concrete. A prominent gap leads to a basement, contributing to the building’s unconventional character. The ground floor is intended for retail use, while the upper three floors contain residential spaces, including a bedroom, living room, and kitchen. A jagged, Escher-like staircase ascends past angled windows and concrete pillars, contrasting sharply with the sleek glass skyscraper adjacent to the site.

Oka, who originally trained in architecture but took a detour into avant-garde dance before returning to the field, embraced hands-on involvement in the construction process to bridge the traditional divide between design and building. He performed most tasks himself, from scaffolding to carpentry for concrete formwork, relying on hand tools and extensive trial and error. His efforts reflect a deliberate response to Japan’s rapid demolition-and-rebuild culture and a desire to create a structure that fuses architectural vision with craftsmanship.

The project faced numerous challenges, including a forced relocation of the building in 2009 due to a redevelopment plan. Arimasuton was moved 12 meters on rails, increasing costs and complicating progress. Financial strains nearly bankrupted Oka, led to the dissolution of his marriage, and required support from his mother and merchandise sales tied to the building.

Reactions to the building have been mixed. Some locals see it as a disruption, citing noise, dust, and interference with views during the prolonged construction. Others regard it as a rare expression of enduring, handcrafted architecture. The building’s resilience was tested but intact during the 2011 magnitude-9.0 earthquake that struck northeast Japan.

The project also attracted collaboration from artists and craftsmen, including manga artist Hideki Arai, who was inspired to document Oka’s story and contribute to construction efforts. Arai praised the building’s improvisational nature and the architect’s vision for a structure designed to endure centuries, adaptable to uses unknown at present.

Currently, Oka is focused on completing the interior so he can reside there and lease the ground floor retail area. In the long term, he envisions Arimasuton serving as a museum or gallery, preserved as a testament to his dedication and an alternative model for Tokyo architecture.

“I’m happy this work came into my life,” Oka said. “I hope it can last another 150 years after I’m no longer here.”