In Tokyo, a city known for efficiency and relentless modernity, Keisuke Oka’s Arimaston Building stands apart. Built entirely by hand over 20 years, it’s an anomaly—a structure born from slow, deliberate effort in a culture of rapid construction.
Oka began this project in 2005, armed with basic hand tools and a vision. The building’s twisting concrete form reveals his improvisational approach, shaped day by day without rigid plans. Its angular windows and irregular surfaces aren’t mere details; they reflect the rhythm of making—decisions carved into concrete with each pour. Oka even incorporated everyday objects like food trays into the formwork, creating subtle patterns and textures that reward close attention.
The building reads like a conversation between sculpture and architecture. It feels personal, almost human, as though each wall carries traces of the hands that shaped it. Despite its unconventional construction, the Arimaston Building is no relic of the past—it’s fully integrated into the urban fabric, yet unapologetically individual.
Now completed, the structure faces an unusual challenge: it is set to be relocated in 2025 due to redevelopment. Using the traditional Japanese hikiya method, the entire building will be shifted 10 meters—a fitting continuation of its already unorthodox journey.
The Arimaston Building is an argument for slowing down, for treating construction as an art form rather than a process of replication. In every imperfect curve and unexpected angle, it asks questions about how we shape our environments—and how they shape us in return.
