Hyakunensha Outer Wall

The Outer Wall of Hyakunen-ya: Eighteen Metres of Concrete Nobody Expected

A garden wall was registered as a national cultural property in 2003. It is 18 metres long and 1.6 metres high, it closes the northern half of the western edge of the Hyakunen-ya property in Tosayamada, Kochi Prefecture, and it is made of reinforced concrete.

That last fact is the surprise. The registry dates the wall to the early Showa era. Reinforced concrete had arrived in Japan by then, but it arrived in banks, department stores, and bridges, in cities, on budgets. Using it for the boundary wall of a private house in a provincial town in eastern Kochi was a choice, and an expensive one, and whoever made it did not treat the material as a shortcut.

The Agency for Cultural Affairs closes its commentary on this wall with four words that do not appear casually in these entries: a wall of singular design.

What Is Actually On It

Read the wall from the middle outward, because that is how it is composed.

Roughly halfway up the face runs a line of openings, diamond-shaped, their edges drawn with a curve rather than cut straight. They are scattered along the wall rather than repeated at fixed intervals, and they perform a division: everything below them is one register, everything above is another.

The upper register carries rectangular openings in two rows, arranged in ichimatsu, the checkerboard. Void, solid, void, solid, offset row to row. The pattern is ancient in Japan and named after an eighteenth-century kabuki actor who wore it on stage. A local walking guide in Tosayamada offers a reading of it that circulates in the town: the pattern continues without break, and an unbroken continuation stands for the prosperity of the household. Whether the builder intended that meaning is not recorded, and the reading should be taken as local tradition rather than documented intent.

The surface between the openings is finished in what the registry calls the German wall manner. Doitsu-kabe was a fashion of Taisho and early Showa Japan, a mortar rendering flung or spattered onto the face and left rough, producing a granular texture that catches light and holds shadow. It came in with Western building and stayed as a distinctly Japanese habit.

Along the top runs a course finished in the manner of coping stone, capping the composition the way a masonry wall would be capped.

Add it up: concrete pretending, in places, to be stone. Openings that admit light and view while enclosing. A geometric pattern with a folk meaning attached to it. A textured render borrowed from European practice. On 18 metres of garden wall.

The Criterion: Not Easy to Reproduce

Japan's registration system, established by the 1996 amendment to the Law for the Protection of Cultural Properties, gives assessors three grounds to choose from. Contributing to the historical landscape of the nation. Setting a standard in design. Not being easy to reproduce.

Across the five structures at Hyakunen-ya, all three were used. The main house and the gate hold up the streetscape. The storehouse sets a design standard. The outer wall, and the inner wall with it, were registered on the third ground: they would not be easy to reproduce.

That criterion is the least intuitive of the three and the most interesting. It is not a judgement about beauty or about fit. It is a judgement about capability. The assessors looked at this wall and concluded that the skills, the practices, and the working conditions that produced it are no longer readily available, so that if it went, it would go for good.

Concrete is the reason. A rendered, textured, pattern-pierced concrete wall built by hand in a small town in the 1930s is not the product of a system that still exists. Modern reinforced concrete is engineered, formed, poured to specification. Nobody today would throw mortar at a garden wall to get a granular skin, then cap it to look like coping, then punch curved diamonds into it and lay the rest out in checkerboard. Not because it cannot be done, but because the reasons for doing it have gone.

The inner wall on the same property, also early Showa, also reinforced concrete, runs 22 metres and carries the same criterion. Between them the two walls account for 40 metres of the boundary and two of the five registrations.

Looking at It

Of the five registered structures at Hyakunen-ya, the outer wall is the one you can examine most freely, because it is the boundary. It runs along the northern half of the western edge of the plot, on the public side, at 1.6 metres, which is roughly eye level.

The property operates as Hyakunen-ya BASE, a whole-house rental guesthouse open to bookings since May 2022. The grounds are private and there is no general admission, but the wall is the part meant to be seen from outside.

Light does most of the work here. A German-wall render is a texture, and texture needs raking light to appear; under flat overcast the surface goes dead. Late afternoon sun across the western face brings the grain up and drops shadow into the diamonds. The checkerboard reads best from a little distance, far enough back that the two rows resolve into a pattern rather than a set of holes.

The site is a two to three minute walk from JR Tosayamada Station on the Dosan Line, about thirty minutes by car from central Kochi. Please respect the privacy of anyone in residence.