Company Profile

Founded in 2001, d/dt Arch. has served both private and commercial clients, providing quality architecture with creative design solutions.
We are dedicated professionals aspiring to design a better future for our society and culture, together with our clients.

Our Vision

Create a better society and culture through architecture.

Our Mission

Contribute to the environment and society by offering the best architectural solutions for our clients.

Our Values

We endeavor to understand and comprehend our clients’ needs, execute creativity, pursue quality in both design and functionality.

Our History

d/dt Arch. originally started as d/dt Design in 1991, co-founded by university friends.

We took "d/dt" from the differential operator in calculus, which defines the slope of a curve at a certain point. No one knows which direction the future will take. However, we believe that quality architecture has the power to not only indicate the direction of the future but also serve as building pieces to create a better society. Therefore, we strive to provide pieces of architecture that will lead us to a better future.

For the first decade, each of the co-founding partners pursued their architecture journey individually, at graduate schools, architecture studios, and real estate firms. In 2001, we renamed our practice d/dt Arch. and started over to work as a team, bringing together our diverse skill sets and work experiences both domestic and abroad.

Since then, we have worked for both private and corporate clients, providing architectural designs and services including project formulation/implementation support, making use of our partner’s expertise and professional networks to the fullest extent.

Meet Our Principal Architects

Yasumi Taketomi

Architect/First-Class Registered Kenchikushi

Yasumi was born in Tokyo, in 1968.
After receiving a BE degree in Architecture from the University of Tokyo in 1991, he advanced to graduate school, where he studied architecture planning and vernacular villages of the world, obtaining his ME degree. Yasumi then enrolled in the M.S. Advanced Architectural Design program at Columbia GSAPP and received his MS degree in 1994.
From 1994 to 2003, he joined Pritzker laureate Arata Isozaki’s practice and worked on major projects worldwide, including the United States, Spain, and Qatar.

"The first time I thought of architecture as a career was back when I was in high school. I saw Arata Isozaki propose a low-rise building for the new Tokyo Metropolitan Government Building in a design competition, while all the other contestants’ proposals were skyscrapers. It was inspiring to see an architect make a social statement through design.

In graduate school, I studied vernacular architecture and villages under Professor Hiroshi Hara. We went on a survey trip to Mexico and I also personally visited a Tibetan colony in Ladakh, India. The striking sights of small buildings in vast landscapes, the merging of man-made objects and nature had a great impact on me. Ever since then, I have always been passionate about exploring ways to contrast or merge architectural pieces with the surroundings, whether in nature or urban settings.

I believe that designing architecture is a social activity that affects not only the owners and the users but also the environment, and it even has the potential to change our society. I aspire to contribute to the environment, society, and our culture by exerting my skills and knowledge as an architect and also engage actively in project direction and management on a larger scale."

Kei Iwata

Architect/First-Class Registered Kenchikushi

Kei was born in Kyoto, in 1967. He received his BE degree in Architecture from the University of Tokyo in 1991 and worked at Tadao Ando Architect & Associates until 1997. At Ando’s firm, Kei was involved in various projects including Asahi Beer Oyamazaki Villa Museum of Art (Underground Jewelry Box annex), Church in Tarumi, Nagaragawa Convention Center, and Harima Kogen Higashi Junior High School. He started as a solo-practitioner architect of d/dt Design until other co-founders joined and renamed it d/dt Arch. in 2001.

"One late summer night, before I knew I wanted to be an architect, I coincidentally saw a TV show titled "Home". It was a documentary about a young client who hired Ando to design his small house, and the long process they went through, involving lots of people, going through many dilemmas and difficulties until the house was finally completed. The program made me realize that behind the process of creation, there are numerous discussions and communications between many people, and it sparked my interest in architecture.
During the years I worked for Ando, I learned a lot while witnessing the passion of clients from all over the world, and the way Ando devoted his energy with even more passion in return.

Throughout my career, I have designed and refurbished many pieces of architecture including residences, medical facilities, educational facilities, and religious architecture. None of them are the same. They involve different people and have their own unique stories. I take joy and pride in being an architect; establishing a diverse network of people through architecture; working with clients, collaborating with other designers, engineers, and contractors; searching for new possibilities of architecture and values as I learn and evolve."

We provide thorough architectural services to bring your ideal project to life: design brief development, site survey, site purchase advice, preliminary to detailed design, building permit and approvals submission, tender assessment, building cost management, construction supervision, etc.

Please do not hesitate to contact us via the contact form for further information or to arrange a free initial consultation session.