Kyoei Steel is one of Japan’s leading steel manufacturers, dedicated to recycling scrap iron through electric arc furnace technology. At its Yamaguchi Division, the new office building was conceived not simply as a workplace, but as an environment where the company’s identity, technological strength, and values could be experienced through light.
Rethinking The Future Awards 2026
First Award | Indoor Lighting (Built)
Project Name: Kyoei Steel Yamaguchi Division New Office Building
Category: Indoor Lighting (Built)
Studio Name: OKUMURA CORPORATION + MR STUDIO Co.,Ltd.
Design Team: Masahiko Tokunaga, Tetsuya Nagayoshi / OKUMURA CORPORATION, Nobuaki Miyashita, Yukari Hirose, Miki Kase / MR STUDIO Co., Ltd.
Area: 3,932㎡（floor area）
Year:2024
Location: Yamaguchi, Japan
Consultants:N/A
Photography Credits: Kenta Sato / JXPhoto Co., Ltd. ,Nobuaki Miyashita / MR STUDIO Co.,Ltd.
Render Credits: N/A
Other Credits: Lighting Design: Atsuko Mihara (LCR, KOIZUMI Lighting Technology Corp.)
The lighting design was developed as an integrated spatial system that reveals the materiality, dimensionality, and symbolic meaning of steel. Rather than functioning as a secondary decorative layer, light was treated as a primary design medium that transforms the company’s own steel products into architectural elements expressing precision, ambition, and innovation.
Throughout the interior, steel products manufactured at the Yamaguchi Division—including equal-angle steel, flat bars, I-bars, and deformed reinforcing bars—were intentionally exposed and incorporated into walls, ceilings, handrails, and feature compositions. Materials usually hidden within building structures were brought to the foreground as finish elements, and the lighting strategy was carefully calibrated to draw out their raw textures, sectional profiles, depth, and rhythm. Concealed linear lighting and controlled directional light create sharp contrasts of brightness and shadow, allowing the steel to appear both powerful and refined.
In the entrance hall, the company’s barcode pattern is integrated into the interior composition as a key design motif. More than a graphic device, this pattern symbolizes traceability, an essential value in steel manufacturing that reflects quality control, reliability, and the continuous tracking of materials and products. Lighting emphasizes the layered steel barcode as a three-dimensional spatial expression, transforming a sign of industrial management into an architectural experience that communicates Kyoei Steel’s identity.
The main focus of the lighting design is the stairwell atrium, where verticality becomes the central spatial theme. In this approximately 20-meter-high space, ninety-three 6-millimeter steel wires are suspended from the upper structure to the floor. Along these wires, five types of equal-angle steel sections are arranged in a composition derived from the company’s QR code, and seamless linear lighting is integrated so that steel and light act as one three-dimensional expression. The brightness, spacing, and visual balance of this installation were repeatedly refined through models and mock-ups.
The stair handrails and west-facing wall further strengthen this concept through layered steel compositions and light. During the day, natural light creates shifting shadows across the surfaces; at night, artificial light intensifies the vertical rhythm and reveals the precision of each element. Through this lighting design, recycled steel is elevated into a medium of identity and beauty, proposing a new prototype for workplace lighting rooted in sustainability, innovation, and brand expression.
