Taisei Kogyo is a diversified construction and engineering group engaged in civil engineering and construction works, real estate sales/leasing and solar power equipment sales, OLY (road surface covering method) equipment leasing and steel frame processing, and telecommunications line maintenance through its subsidiary Tokyo Telecom Engineering Co., Ltd. The company holds proprietary patented construction methods including the OLY road surface covering method and the Picalus pipe-in-pipe method, providing differentiated technical capabilities in urban civil engineering. The group primarily serves public sector clients including the Tokyo Metropolitan Government's sewerage bureau, with operations centered in the Kanto region and a branch in Nagoya.