Nikken Sekkei, established in 1900 as an offshoot of Sumitomo Corporation, is a prominent Japanese architectural, planning, and engineering firm headquartered in Chiyoda, Tokyo. Initially named Sumitomo Temporary Architecture Department, the company gained independence in the 1950s, becoming Nikken Sekkei Komu Co. Ltd. Today, it's a privately held company, partly owned by its employees, and operates globally. Nikken Sekkei offers a comprehensive range of services, from architectural and interior design to urban planning, landscape design, and various engineering disciplines, including structural, MEP, and civil engineering.