Built from the ground up by architect Masato Igarashi, this Tokyo home replaced rooms with levels – where books climb the walls, and concrete glows with light.
“I work in the office on the first floor every day. I’m surrounded by my books and plants. I love the light that comes in at unique angles throughout the day.”
“This is probably my favourite room in the house. It’s fascinating to see how the sunlight changes throughout the day and transforms the space.”
“We both like to talk about our day, so we designed a house that allows us to talk wherever we are.”
To fully appreciate architect Masato Igarashi’s Tokyo home, it helps to go back to his childhood. “I loved playing with Lego when I was little,” he says. “I would build things by following the instructions, but I liked deconstructing them once they were finished and mixing the pieces with others. I decided I wanted to do that as a job.”
Igarashi’s home, built on just 31sqm/338sqft of land, layers the freedom of his childhood imagination into a sophisticated use of vertical space that’s genuinely fun. Although it may seem like a typical three-storey house from the outside – a large, glass-sided concrete structure – the interior is organised across seven staggered platforms. And remarkably, barring the bathroom, there are no internal walls. Instead, the platforms, or skip floors, work to not only create distinct zones throughout the home, but to also turn circulation paths into usable surfaces: steps become benches, ledges become desks. Another value that, for Igarashi and his wife, cannot be overstated is the visual and acoustic connection they allow: “We both like to talk about our day, so we designed a house that allows us to talk wherever we are. It also gives a sense of what the other person is doing.”
Moving through the house feels less like stepping between rooms and more like rising through layers. You enter through the genkan – a traditional Japanese entryway where shoes are removed – and step into Igarashi’s office, where a double-height ceiling allows for an abundance of plants and filtered light. The kitchen sits mid-level, bridging work and home life, while one level up on a skip floor, the living and sleeping spaces open beneath five-metre ceilings. One level higher, the bathroom is tucked just beneath the roofline, with glass walls that let in the sky. Across from the bathroom, above the bedroom, a small ladder leads to the rooftop, a quiet perch above the city, perfect for watching fireworks in the summertime.
Designing the home from scratch gave Igarashi the freedom to shape it around his interests and hobbies, including his ever-growing collection of books. The main bookshelf, which reaches six metres, spans two floors and holds 5,000 books – and counting. “The first floor is for the architectural books I use for work. The second floor above is for manga, novels, and other non-work-related books,” Igarashi explains. Clearly someone who believes you can never have too many books, Igarashi designed a second bookshelf that forms a headboard on their sleeping platform. On weekends, the couple uses the area as a cosy place to read. That is, if they’re not reading in the other reading nook by the entrance. Beyond these designated spots, Igarashi explains that the real beauty of this home lies in its flexibility: “We have designed the home to change according to how we spend our time, without clearly defining the purpose of each space.”
Concrete gives the home its form; light brings it to life. But it's not just the material itself – the texture of the concrete walls carries the imprint of the wooden formwork used to cast them, adding a tactile, almost organic quality. Igarashi says, “The walls and ceiling are made of fair-faced concrete, and the light comes in from various directions depending on the time of day, making the texture of the concrete look beautiful.”
Across the house, the windows are designed not just to let in light, but to shape how it moves and feels – whether through a discreet opening at the entrance, a slim kitchen window at the back, or a full-height glass wall in the bathroom. In the office on the ground floor, a high-set window brings in daylight while preserving privacy, illuminating the long bookshelf wall. Throughout the day, light moves across the concrete like a slow brushstroke, shifting in tone, softening hard edges and bringing warmth to surfaces that might otherwise feel stark.
With its layered platforms, abundant light, a huge bookshelf climbing the wall, and plants galore, the home feels like a concrete treehouse for grown-ups. And while it was designed for two people, Igarashi looks to the future: “I hope that what we use as a house now will be used as something else – perhaps a café or a museum – when it is passed on to other people, and that it will remain in a different form and be used for a long time.” Shaped by movement, light, and memory, it’s a home built not only to endure but to evolve. Sustainability, here, is as much about mindset as materials.
