Motoshi Yatabe grew up on a quiet, almost ruralstreet in Japan’s Saitama Prefecture. There was a vegetable garden in front of his childhood home and a rice field across the street—plenty of room for him and his sister, Masako, to play. Sited roughly 15 miles outside of central Tokyo, it had yet to be colonized as part of the Greater Tokyo Area. Today, each block is lined by single-family homes packed shoulder to shoulder like commuters on a Tokyo subway.

To say that Tokyo is dense is to trade in old aphorisms: salarymen in capsule hotels, bento box–size houses, minivans that are truly mini, and sidewalks that pulsate with throngs of people. The spaces that result from these conditions (the best of which marry pricey real estate with high design) are fetishized, especially in the West. But suburbs like Saitama, which was established as its own city in 2001, have grown over the past 30 years to tell a different story. What began as loose sprawl has grown denser and denser.

Yatabe, along with his parents and sister, moved out of their old house before development boomed, but the family held on to the increasingly valuable property. As the neighborhood matured, so did Yatabe. He’s now married to Yukiyo, has two young sons, and works for the family business, Yatabe Steel Fabrication. The company was founded by his grandfather after World War II and was handed down to his father; Yatabe is next in line.

In 2005, he began talking to Masako’s husband, architect Russell N. Thomsen, about building a new home on the Saitama lot. (The old house had been razed years earlier.) “I have wonderful memories about the old house where we grew up,” Yatabe recalls. “I wanted that same feeling in our new house. I wanted it to be a place where our families could get together, where friends would enjoy visiting.” Thomsen began working on the design in 2006, when he was teaching at SCI-Arc’s study-abroad program at Kyoto Seika University for a semester.

Back in the States, Thomsen’s and partner Eric A. Kahn’s Los Angeles–based firm, IDEA Office, working with Ron Golan, translated Yatabe’s desires into a straightforward program: a master bedroom, bed-rooms for the boys, a hobby/office space, and a lofty main room to accommodate living, dining, and cooking. At 1,000 square feet, the two-story house efficiently answers the family’s needs.

However, with a black metal facade on the street, it doesn’t immediately resemble the kind of inviting abode Yatabe envisioned. The tight, south-facing site complicated matters, leading the architects to screen for both sun exposure and privacy. Local typologies offered few clues. In response to growing density, zoning regulations control the height and setback from the street, so homes in the neighborhood all follow a similar pattern—boxy profiles that feature shallow balconies and meager gardens.

By pushing the facade toward the street, the architects liberated the design from these restrictions. Hidden behind the black enclosure is a glass facade that looks onto an ample outdoor space open to the sky: a shady garden on the lower floor and a sheltered terrace just off the living room on the second floor. (A steel brise soleil keeps the south-facing glazing cool.) Painted white, with a perforated screen to shield the garden from the adjacent property, the space is luminous. Each room in the house enjoys views of the garden and terrace, where the quality of light changes throughout the day. A single maple tree and pots of bamboo add touches of green.

Although the distinctive structure sticks out on the block, it does take some inspiration from vernacular Japanese architecture. Outdoor living is part and parcel of Los Angeles architecture, and the European and California modernists do inform IDEA Office’s work. But Thomsen was also influenced by machiya, townhouses typical of the Kyoto area, which feature small courtyard gardens that similarly relate inside and outside. As much as Thomsen draws on tradition, in Japan he’s a Western architect. And he’s okay with that. “I’ll always be a foreigner, but ideas from the West have always been incorporated, tweaked, and made Japanese,” he notes.

Indeed, one space that makes the house so comfortable is what’s locally referred to as the “LDK,” for living, dining, and kitchen. It blends Eastern and Western sensibilities, and with no walls between the different areas and a 12-foot-high ceiling, it’s a spot for the family to gather and entertain. It resembles a loft, but it’s also like traditional Japanese houses where shoji screens make it possible for rooms to be flexible, not dedicated to a single purpose. A prefab kitchen and custom-made storage cabinets line its perimeter, but otherwise the room is simply defined by what you put in it—couches or tatami mats. “It’sa space that cuts across cultures,” explains Thomsen. “It represents an informality that is more prevalent in Japan these days.”

Cultural exchange was a literal part of the design and construction process. IDEA Office collaborated with Tokyo-based architect Masao Yahagi. Once the scheme was set in Los Angeles, a final model was shipped overseas. Yahagi developed the construction documents, engineering and drawing the house to meet local standards, and set up a construction blog, so IDEA Office was able to see daily posts.

During the process, Thomsen returned to Japan several times to work on details. There’s potential for the exchange to go both ways. Back in Los Angeles, Thomsen considers how the house could influence his hometown. “Good architecture is not necessarily big architecture,” he says. “Smaller buildings, such as this house, can challenge the creativity of an architectin unexpected ways. It takes a shift in cultural understanding about how to do more with less.” In California, it’s unsustainable to keep building subdivisions. The Japanese embrace of density is not dark and dystopic as imagined in science fiction, but light-filled and efficient. Most importantly, it still feels like home.