Okano Valve Mfg. Co., Ltd.

Okano Valve Mfg. Co., Ltd. (岡野バルブ製造株式会社) is a Japanese industrial valve manufacturer founded in 1926 by Mitsuru Okano, a former chief engineer and West Japan general manager for a British boiler maker. Headquartered in Kitakyushu, Fukuoka, the company was established with the specific mission of domesticating high-temperature, high-pressure valves for power generation, which until then had been entirely imported. After six years of research and prototyping, Okano delivered Japan's first domestically produced high-temperature, high-pressure valve in 1932, using Stellite hardfacing on valve seat surfaces — a world-first achievement that became a global standard. The company's valve products carry the trademark "SUPERO," a name derived from "SUPERIOR" with an Esperanto-style "O" ending, expressing the ambition to surpass first-class foreign products. Okano is known for supplying valves to Japan's first commercial nuclear power plant, the Tokai Power Station, in 1963, and has since delivered over one million valves to more than 60 countries. Its valves are used in ultra-supercritical (USC) thermal power plants, small modular reactors (SMRs), and high-temperature gas reactors (HTTRs). Beyond manufacturing, Okano operates a substantial maintenance business that began in 1954 and now exceeds valve manufacturing in revenue scale. The company maintains valves and related equipment not only for its own products but also for competitors' valves, serving industrial plants across Japan and worldwide. In 2021, Okano refreshed its management structure and adopted a philosophy of "post-capitalism" and "meaning value management," emphasizing social contribution alongside financial value as it celebrated its 100th anniversary. The company remains privately held and is led by President Takeharu Okano.

Okano Valve Mfg. Co., Ltd. was founded in 1926 as Okano Shokai by Mitsuru Okano, a British boiler maker's West Japan general manager and engineer. Okano was concerned that valves, the most failure-prone components of boilers, were entirely imported, and that a valve failure could render a boiler unusable for months. He founded the company with the ambition to domesticate high-temperature, high-pressure valves. After relentless research and prototyping, the company delivered Japan's first domestically produced high-temperature, high-pressure valve six years after founding. In 1932, it succeeded in domesticating high-temperature, high-pressure valves for thermal power generation. The company discovered Stellite (Haynes Stellite) as a material that could withstand temperatures of 450°C, dramatically extending valve life. Stellite hardfacing on valve seat surfaces was a world-first achievement, and Okano chose to disclose the technology to domestic and international manufacturers, based on the belief that openness generates new technology. This Stellite application became a global standard and laid the foundation for Okano's "one step ahead" philosophy. In the nuclear field, Okano began development in line with national policy. It was appointed as a managing company of the Japan Nuclear Ship Research Association's study group and achieved results as a core developer of nuclear valves. In 1963, after seven years of research, it began full-scale production and delivered all steam valves for the Tokai Power Station, Japan's first commercial nuclear power plant, which began operation in 1966. All were Japan-firsts. Subsequently, with the construction of nuclear power plants in Tsuruga, Fukushima, and elsewhere, Okano advanced its technological innovation and added value, becoming capable of manufacturing all types of high-temperature, high-pressure valves for nuclear power. To date, Okano valves have been delivered to power plants in 60 countries, exceeding one million units. Even now, Okano is present in the development of ultra-supercritical (USC) thermal power, small modular reactors (SMR), and high-temperature gas reactors (HTTR), establishing a global niche top position as a valve maker with quality that competitors cannot match. The maintenance business, now a core business, began in 1954. Initially handling repairs and safety valve adjustments, it grew as product complexity increased the need for manufacturer maintenance. Starting with two people, the maintenance department reached 100 people by 1976. At its peak before the Great East Japan Earthquake, it had over 300 people including partner companies, operating from nine domestic bases and serving industrial plants in Japan and worldwide, maintaining not only Okano valves but also competitors' valves and non-valve equipment. The maintenance business has exceeded valve manufacturing in revenue scale, and recently the company has been digitally arming its craftsmen. High-temperature high-pressure valves are welded to piping and cannot be brought back to the factory for inspection and repair; a mistake can be fatal, and power supply would stop if work is not completed on-site. This environment turned rough workers into professionals and further polished the Okano spirit. In 2021, Okano refreshed its management structure. As a long-established manufacturing company with a century of spirit, technology, and tradition walking with the development of social infrastructure such as the power industry, it has embraced new social trends such as DX and creative while inheriting its underlying ism, and is promoting new businesses and regional revitalization. The company celebrated its 100th anniversary and adopted a philosophy of "post-capitalism" and "meaning value management," pursuing both financial value and meaning value — the value of the meaning that corporate activities give to society and people. Okano believes that its meaning value lies in rebuilding industry and regions, making the world better, and giving the next generation hope for the future.

• 2026

  Celebrated 100th anniversary; sponsored ROX 2026 robot contest and signed sales agency agreement for Nolvis X1 inspection drone.

• 2021

  Refreshed management structure; adopted post-capitalism and meaning value management philosophy.

• 1976

  Maintenance department reached 100 personnel.

• 1963

  Began full-scale production of nuclear valves and delivered all steam valves for the Tokai Power Station, Japan's first commercial nuclear power plant.

• 1954

  Maintenance business began.

• 1932

  Succeeded in domestic production of high-temperature high-pressure valves for thermal power generation; world-first Stellite hardfacing on valve seat surfaces.

• 1926

  Founded as Okano Shokai by Mitsuru Okano.

Global niche top manufacturer of high-temperature high-pressure valves for power generation, with integrated maintenance services and a philosophy of meaning value management.

• High-temperature high-pressure valves for thermal power

• Nuclear power valves

• Safety valves

• Steam valves

• Valve maintenance and repair services

• Nolvis X1 indoor inspection drone (sales agency)

1. 1岡野バルブ製造株式会社 公式サイトokano-valve.co.jp
2. 2HISTORY HIGHLIGHT OKANOの歴史okano-valve.co.jp
3. 3OUR STORY 矜持 企業理念okano-valve.co.jp