The duo was asked to renovate the ground floor of a 20-year-old duplex property in a residential area of Setagaya, a ward in Tokyo, where the client lives below his parents.
The renovation involved removing a partition wall that previously separated the kitchen-diner and living area, and also adding a small workspace that leads into the bedroom.
"The removal work was minimal," explained Matsuba, whose past projects include a house that bridges the flat rooftops of a dental clinic and garage.
"The main thing that we removed was the partition wall between the dining-kitchen and the living room – it became functionally unnecessary," he said.
After taking out the partition wall, the wooden beams – or "two-by-four members" – used within the construction of the building were revealed.
"We intentionally kept these members exposed to demonstrate how old this house is and the manner of its construction," said Matsuba. "We wanted to keep the previously hidden history of the house visible in the interior space."
Aiming to keep costs to a minimum, the architects opted to apply new flooring materials directly on top of the existing tiles.
Wooden flooring in a herringbone pattern runs throughout the open-plan kitchen and living space, while large floor tiles were used in the additional office room. The walls were covered in plasterboard before being painted white.
"In this project, we avoided removing the existing finish where possible," said Matsuba. "We applied the new material directly onto the original finish."
Leaving structural elements exposed is a popular trend among Japanese home renovations. Other examples include an apartment that combines unfinished concrete and exposed plywood, and a loft where concrete beams are speckled by swathes of white paint.
Photography is by Tomoki Hirokawa.