The city of Tomioka in Japan is known for its world heritage Tomioka Silk Mill. Within its dark-brown townscape, The Tomioka Chamber of Commerce and Industry purchased ‘Yoshino Gofuku-ten’, a traditional Kimono store, to relocate to.

Designed by Tezuka Architects, the project began as a rejuvenation of the historical landscape, brought about due to a road expansion that saw the demolition of the old conference hall.

The inside of the Tomioka Chamber of Commerce and Industry.  Image credit: Katsuhisa Kida/FOTOTECA

The inside of the Tomioka Chamber of Commerce and Industry.  Image credit: Katsuhisa Kida/FOTOTECA

It is often difficult to maintain a traditional shop in its original form. Unlike in private houses, it is destined to be redesigned according to daily needs. Yoshino kimono store was no exception, as it had undergone some haphazard renovations – many timber columns had been cut off and were reinforced by a steel framework. It was a wonder how it had retained its form to this day. The main house began to collapse, and soon all it had left was the street facade. It became a hazard and was immediately removed, only its roof tiles were to be preserved. The storehouse, despite losing some pillars, was able to be reinforced and conserved. The two preserved roofs were capped with plaster-works traditional to the area; the storehouse with its original, and main house with a reconstruction.

The building is composed of repeating roof ridges, devised in respect to the traditional townscape. The form is also intended to establish the structural system, as sketched out from the initial stage. The intention was to copy the impression of the wooden truss of Tomioka Silk Mill.

However, merely duplicating the old structure is uninspiring – it had to represent Tomioka as the city of the future.

In this building, the diagonal members are not used as truss beams like in the Silk Mill but rather used as elements that create planer rigidity. The planes meet with each other at their edges, creating a monocoque effect. With angle braces and knee braces supporting the framework, the result is a geometry that clearly shows the dynamics of the force.

Timber building is both the oldest and the latest building technique. The true value of timber construction is that it allows continuity of details from structure to fixture. In this way, the new Chamber of Commerce is a genuine timber building, made possible by the skills of craftsmen.

A real wooden building does not get old; it matures, gains character, and looks better with time. A diagonal grid pattern appears repeatedly from the structure to the awning screen. Even the bookshelves are composed of the same pattern. Initially, the pattern was derived from the building form of the roof ridges. However, it’s been since pointed out that it resembles the lattice that is used in silkworm farming. The pattern is also similar to the ‘Namako wall’, a design with white clay joints that are widely used for fireproofing storehouses, including that of the Yoshino kimono store.