BIG's First Japan Buildings Are Made of the Island Itself

BIG's debut in Japan is a trio of rammed earth villas on a remote Seto Inland Sea island whose load-bearing walls are built from the soil excavated during construction.

Landlord Ledger Publications • Profile • 2026-05-08

On a remote island in the Seto Inland Sea, the walls of a new villa are not concrete or glass or prefabricated panels. They are the island. The soil excavated from Sagishima's hillside to carve out the foundation was mixed, compressed, and layered into the load-bearing rammed earth walls that now frame floor-to-ceiling views of the archipelago. NOT A HOTEL Setouchi opened on April 1, 2026, marking the first completed buildings in Japan from global architecture firm BIG (Bjarke Ingels Group). It is one of the more quietly radical things to happen in luxury real estate in years: a property whose very structure is indistinguishable from the ground beneath it.

An Architect, an Island, and a Walk That Wrote the Design

BIG and Japanese hospitality startup NOT A HOTEL began their partnership in 2022. The site chosen was the southwestern cape of Sagishima, a small island in Hiroshima Prefecture that sits within the Setouchi region, a stretch of Japan's inland sea that has drawn international attention over the past two decades as a destination for contemporary art, architecture, and natural beauty. The Setouchi Triennale, held across the islands of the region, has helped transform the area into a byword for serious design tourism. For NOT A HOTEL, which was founded in 2020 by tech entrepreneur Shinji Hamauzu on a premise that luxury homes should be shared rather than owned outright, the region was an obvious fit.

BIG's design logic for the site was determined by a walk. BIG partner Leon Rost described the experience of tracing the terraced contours of the peninsula on first visit: "That walk wrote the architecture. Each step along the hillside became the curving forms of the villas, their long facades opening to capture the panoramic sea." The three resulting villas were positioned at different points along the cape and named for the degrees of sea view they command: 360, 270, and 180. Villa 360, perched at the highest point, deploys a ring-shaped plan around a private courtyard that opens to the sky; Villa 270 places an infinity pool at its center, its living spaces arranged around the water like islands; Villa 180, set along the northern cliff face, curves along the rock and surrounds a Japanese garden with seasonal trees and a private open-air bath. Each villa provides four bedrooms with capacity for eight to ten guests and a total floor area between 707 and 786 square meters.

Walls Built from the Ground Down

The central material fact of NOT A HOTEL Setouchi is one that distinguishes it from almost every other high-end resort opened in 2026. The structural walls of the three villas are not imported or manufactured; they are built from Sagishima's own soil, compacted using the rammed earth technique, a construction method with roots in antiquity that has found renewed interest among architects seeking buildings with minimal material footprint. The process requires extracting earth from the site, testing its composition, and compressing it in successive layers within formwork to produce dense, load-bearing walls with a distinctively striated surface. The result carries the color and texture of the place itself, and its thermal mass properties help regulate interior temperature without mechanical systems.

Construction took less than two years. Collaborators included Maeda Corporation, ARUP Japan, and structural firm 1moku. Prior to breaking ground, native vegetation including grasses, olive trees, and lemon trees was harvested from the 30,000-square-meter site. After completion, those same plants were reintroduced around the finished buildings. Rooftops are clad in low-reflective solar panels; rainwater is collected and returned to the landscape. The island was not stripped for the construction. It absorbed it.

Scandinavian Logic Through Japanese Eyes

BIG's design language for the villas draws openly on traditional Japanese architecture while filtered through a Scandinavian spatial sensibility. The glass facades, which run floor to ceiling and dissolve the boundary between interior and exterior, are a direct reinterpretation of the shoji screen: the sliding rice-paper panel that mediates between private and shared space in the Japanese vernacular. The black Genshoseki slate floors translate the modular geometry of tatami mats into a contemporary material. The spinal walls of each villa create inward-facing protected spaces open only to the sky, a reference to the courtyard logic of traditional single-story Japanese houses.

Bjarke Ingels described the villas as "architectural oxymorons embodying seemingly contradictory elements into a holistic hospitable whole." The quote captures the ambition accurately. These are buildings that simultaneously look outward to the sea and inward toward a protected garden, that use ancient construction and modern energy systems, that read from a distance as extensions of the topography and from inside as contemporary open-plan residences. The tension between those poles is the design.

The Ownership Model That Built It

NOT A HOTEL Setouchi would not exist without the financial model that made its construction possible. Founder Shinji Hamauzu, who left Zozo Group in 2020 during the Tokyo Covid lockdown to build what he described as "not just another hotel," created a company that inverts the conventional hospitality development sequence. Rather than building a property, financing it, and then selling nights, NOT A HOTEL sells fractional ownership stakes before construction begins. Each stake entitles the owner to a set number of nights per year; the capital raised from presales funds the build.

For SETOUCHI, ownership is divided into 1/36 fractional stakes, each priced at approximately $2.6 million USD (389 million yen). The smallest stake grants 10 nights per year; larger shares scale accordingly. Owners are registered on the Japanese property registry and hold legal title to their share. Nights can also be traded across NOT A HOTEL's wider network of properties throughout Japan, which includes collaborations with designers ranging from Japanese architecture practices to NIGO, the influential fashion designer who conceived a villa in Tokyo. The model won the Wallpaper Design Award for Best Timeshare in 2023 and has attracted international buyers who want access to Japan's most architecturally serious properties without the full burden of solo ownership.

As of the fourth sales phase in early 2026, six of the 36 shares remained available.

Accessible by Helicopter or Speedboat Only

Sagishima is not a place one stumbles upon. The island sits in the middle of the Seto Inland Sea, accessible from the mainland by private speedboat or helicopter, both of which NOT A HOTEL arranges for its owners and guests. There is no public ferry connection included in the property's access protocol. The property also includes a beachfront restaurant and access to a private beach.

The experience is being extended into the water. In early summer 2027, NOT A HOTEL is scheduled to begin operations of the SUNREEF 80 POWER NOT A GARAGE EDITION, an 80-foot luxury power catamaran built by Polish manufacturer Sunreef Yachts with interiors curated by NOT A HOTEL. The vessel, sold separately under NOT A HOTEL's mobility-sharing platform "NOT A GARAGE," allows owners to extend their stay from the island into the surrounding archipelago. Under the NOT A GARAGE model, purchasing one mode of mobility grants access to others across land, sea, and air.

A New Standard for What Ownership Means

BIG's Setouchi project arrives at a moment when the definition of luxury property ownership is being actively renegotiated. The fractional model that NOT A HOTEL has developed is neither timeshare nor private club in the traditional sense; it is deeded, registered, legally recognized co-ownership of a specific property, with the management obligations and access logistics handled professionally. For international buyers seeking access to architecturally significant properties in Japan, a country that has seen sustained growth in inbound real estate interest over the past decade, the model offers a path that solo acquisition at this scale would not.

The rammed earth detail matters beyond aesthetics. Buildings made from site-excavated soil have a different relationship to their location than buildings assembled from transported materials. They cannot be replicated elsewhere. The specific clay composition of Sagishima's ground, the color it produces, the texture of its compression layers: these are properties of that place and no other. Bjarke Ingels framed it as the logic of a landscape painting come to life. Shinji Hamauzu framed it as a mission to "make Japan even more valuable." What the walls actually demonstrate is something simpler than either description: that building from where you are, rather than importing what you need, produces architecture that belongs to a place in the most literal sense possible.