Asphalt is more commonly known today for its use in road and other infrastructure, but it has historically been used in Japan to fasten wooden shafts and in stone arrowheads to make steadier weapons during the Jomon period (14,000 – 300 BCE). The techniques, methods and distinct pre-industrial usage render the material with a unique design sensibility that is outweighed by its 'practical' industrial applications today. This gap between the ways materials are historically used and conventionally understood became a turning point in the creative endeavours of the Japanese designer So Koizumi. In his latest furniture design collection, As, he draws from the history and cultural significance of asphalt, bringing together formally distinct materials including metal, stone, resin, aluminium and brass. “By reconsidering asphalt in its original role as a material that mediates between disparate elements, my approach naturally began to diverge from conventional ideas of contemporary furniture design. From that perspective, it felt almost inevitable that new dialogues would emerge between the materials,” Koizumi tells STIR, expanding upon the use of the somewhat unconventional material in his collection.

In November 2025, Koizumi helmed an exhibition for the As collection at Gallery MATOYA in Aichi, Japan.The collection comprises a stool, a chair design, a side table, a light fixture in two size variations and three wall-mounted product designs, all complementing each other with an unmistakable vocabulary of contemporary design. All the pieces are conceived as neat assemblages of planes and cuboidal volumes with different materials, held together by asphalt as not just the binding agent, but also as veritable design language. “Asphalt could be understood as a mediator between disparate materials, and once viewed this way, the possibilities for expression expanded dramatically. For that reason, instead of concentrating this concept into a single piece of furniture, I chose to develop it across multiple objects. By articulating the idea through different forms, I wanted to make the concept itself more tangible and three-dimensional,” the designer tells STIR.

Throughout the process of creating the pieces, the designer unravelled these relationships by carefully studying the specific qualities of every material, from its granularity and gloss to colour and workability. The forms emerged gradually as he explored the possibilities of the fusion of these materials. The designer describes this act of 'creating' the material itself as an integral part of the design process.

Expanding on this, the Japanese designer states, “I believe that the act of creating the material itself is directly connected to originality. At the same time, when working with a new material, I feel that it is impossible to design without physically engaging with it—moving my own hands and developing an embodied understanding of its characteristics. Becoming curious about a material, taking action on that curiosity and carrying the process through to completion by means of repeated experimentation is, I think, one of the defining qualities of my design practice”.

He founded his practice, So Koizumi Design, in Tokyo in 2021, engaging in a range of projects—from spatial design to furniture and product design. Striving to build new relationships among people, objects and environments, his practice re-examines materials and their inherent structures and possible assemblages. Building on that, the designer has also recently released a new lighting design, Nave, and a sculptural ladder, Resonique, following the release of the As collection to acclaim.

Nave, a bespoke design for lighting a villa, focuses on architectural space and the visual of light descending from a high ceiling reminiscent of a church architecture. Symbolising the form of a roof, the stainless steel and aluminium light fixture is designed as an envelope around the light source. Placed atop a bar counter in the villa, the object is suspended on a rotating structure that allows the position of the light to shift in response to the user’s need.

While Nave is inspired by architecture itself, Resonique draws from the elegance of brass musical instruments. The design, created as a part of a project within the new employee training program of the Japanese design and construction company Tanseisha Co., Ltd., was a result of a collaboration between the designer and a resident team at the company. It boasts a sculptural design quality that fuses functional sensibility with a mix of curved and straight stainless-steel elements, challenging the conventional image of a ladder.

Together, these objects portray a creative journey of authorship through experiments, assemblages and a sense of exploration and inquisitiveness in material enquiry that end up elevating both medium and product. Koizumi's fresh repertoire serves as an interesting rejoinder to framing the future of Japanese contemporary design as innately drawing from a rich past.