Sato Family Retirement House

A Concrete Retirement House Above the Ayugaki River

The Sato Family Residence Inkyoya (佐藤家住宅隠居屋, Satō-ke Jūtaku Inkyoya) is a two-story reinforced concrete retirement house at Kasagi in Nyūta-chō, Tokushima City, built in 1928 and entered on the national register of Tangible Cultural Properties on 25 April 2014.

An inkyoya is a separate dwelling for the household head who has passed the family business to the next generation. In Japanese country houses these are usually modest timber buildings set behind or beside the main house. This one is not timber. It is concrete, and it was poured at a moment when concrete had barely reached the private houses of provincial Japan.

The building occupies the northern part of the western edge of the property, a compact block with a footprint of 56 square meters and a small tower, or tōya, rising above the roofline. Its plan splits in two. The northern half was built as a storehouse. The southern half is a tatami-floored zashiki, the formal room where guests are received and where the family's better furnishings live. A bathroom breaks out of the rectangle on one side, a small projection that gives the volume its slightly irregular outline.

Look at the walls and the concrete disappears. Every exposed surface carries a coat of arai-dashi mortar, a render loaded with stone chips that is sprayed and brushed with water before it fully cures so the aggregate rises to the face. The plinth, the hood above the entrance and the tower itself all received the same treatment. From a few paces back the building reads as cut stone.

Why It Was Registered

Japan's register of Tangible Cultural Properties, created in 1996, sits below the older system of designation as an Important Cultural Property. Registration carries a lighter regulatory load: owners continue to live in and use their buildings, notifying the state only when they intend to alter the exterior substantially. It was designed for exactly this kind of holding, a working private property of the modern era that would otherwise slip away unrecorded. Tokushima Prefecture counted 217 nationally registered cultural properties as of April 2024.

The Agency for Cultural Affairs registered the Inkyoya under the criterion covering works that would be difficult to reproduce. The reasoning turns on a combination rather than on any single feature: early reinforced concrete construction in Tokushima Prefecture, executed by plasterers still working in a pre-modern craft tradition.

That pairing deserves a moment. Reinforced concrete entered Japanese building practice in the 1900s and 1910s, and through the 1920s it spread across the provinces mainly in banks, schools, hospitals and government offices. Private houses came much later. Tokushima City has one celebrated exception in the Mikawa Family Residence, a three-story concrete house with a tall observation tower built for a physician at roughly the same date and later designated an Important Cultural Property. The Sato Inkyoya belongs to that same brief window, at a far smaller scale and without an architect's name attached to it.

There is a practical logic underneath the ambition. The northern half of the building was a storehouse, and storehouses in Japan had for centuries been built as thick-walled dozō precisely because fire was the constant threat. Concrete solved the same problem by other means. Wrapping that fireproof box in stone-like arai-dashi and attaching a formal tatami room to its southern side produced something that behaved like a modern structure while looking like a masonry pavilion.

A round of repair work was carried out in 2013, the year before registration. The gateposts standing at the southern entrance to the same property were registered on the same day under a separate entry. The main house of this Tokushima City branch of the Sato family is not itself on the register.

What to Look For

The tower is the first thing that registers from the road. On a building of this size a rooftop structure is a deliberate gesture, and it pulls the eye upward in a way the 56-square-meter footprint would not otherwise justify.

Closer in, the arai-dashi repays attention. The illusion of stone holds at ten meters and breaks at one, where the individual chips of aggregate become visible in their mortar bed and the hand of the plasterer shows in the density and evenness of the wash. Craftsmen who learned their trade finishing earthen walls were applying that eye to a material with entirely different behaviour, and the seams and edges are where you can see them working it out.

The junction between the storehouse half and the reception half is worth tracing along the elevation, as is the bathroom projection, which interrupts the block in a way that a purely decorative design would have avoided.

One important caution. This is a private residence in active use, and no public opening has been announced by the owners, the city or the prefecture. There is no interior access, no visitor entrance and no admission fee, because there is nothing to admit visitors to. What can reasonably be done is to look from the public road, and even that should be done briefly and without entering the grounds. Photography from the roadway is a matter of courtesy rather than rule; do not photograph into the property.

The address sits west of central Tokushima, roughly twenty minutes by car along the Ayugaki River on the road that continues toward Kamiyama. Public transport in the area is thin, and there is no visitor parking at the site. Travellers wanting a destination that actually welcomes them will find the Awa Historical Site Park and the Tokushima City Archaeological Museum in nearby Kokufu-chō, set among the burial mounds of Mount Kinobe, and the Shikoku pilgrimage temples of the Tokushima plain within a short drive.