Okumura Group Co., Ltd.

Taikane Okumura founded the civil and construction contracting business. After his father's death, he decided to persevere through adversity and entered the world of civil and construction contracting at the age of 27.

Founder of Okumura Group, Tahei Okumura, established a civil engineering contracting business. Five days after his father's death, the responsibilities for his mother and young siblings fell to Tahei. "I am prepared to dive into any difficult situation and endure with patience. I want to take on tasks that others shy away from," he decided, entering the world of civil engineering contracting.

Founding

On February 22, 1907 (Meiji 40), five days after his father's death, the lives of his mother and young siblings fell under the care of Tahei Tahei. "I am prepared to dive into any difficult situation and endure with patience. I want to take on tasks that others shy away from," he decided as he entered the world of civil engineering contracting. This was the departure of the founder of Okumura Group, Tahei Okumura, at age 27.

On February 22, 1907 (Meiji 40). Five days earlier, his father died, and the lives of his mother, younger brother, and sister fell under Tahei's care. "I am prepared to dive into any difficult situation and endure with patience. I want to take on tasks that others shy away from and find challenging." With this resolve, he entered the world of civil engineering contracting. It was the departure of 27‑year‑old founder Tahei Okumura of the Okumura Group.

The head office was opened in Shimotada Village, Kita-Katsuragi District, Nara Prefecture. The first project was the construction of the special high-voltage transmission line for the Taisho Hydropower Electric Kobe Main Line, Section 2.

Established the headquarters office in Shimotada Village, Kita-Katsuragi District, Nara Prefecture. Okumura Group's first project was the "Taisho Hydropower Electric Kobe Main Line, Section 2, Special High-Voltage Transmission Line Construction Work."

Established the head office in Shimotada Village, Kitakatsuragi District, Nara Prefecture.

Won the first project of Okumura Group: the "Taisho Hydropower Electric Kobe Main Line, Section 2, Special High-Voltage Transmission Line Construction Project."

Opened Okumura Group's headquarters in Osaka City.

Opened the Okumura Group head office in Osaka City.

The business of Okumura Group, originally run by Taikane Okumura, was inherited and Okumura Group Co., Ltd. was established.

Founded Okumura Group Co., Ltd. The company inherited the business of the privately owned Okumura Group run by Tahei Okumura, and Okumura Group Co., Ltd. was born.

Founded Okumura Group Co., Ltd. Tahei Okumura inherited all of the business of the privately owned Okumura Group, and Okumura Group Co., Ltd. was born.

In response to the enthusiasm of the local Shinsekai community who wished for the revival of the demolished Tsutenkaku Tower during wartime, the reconstruction was undertaken, and after about a year of work, the second Tsutenkaku Tower was completed.

Constructed the Tsutenkaku Tower. Responding to the enthusiasm of the local Shinsekai residents who wished for the revival of the Tsutenkaku Tower dismantled during wartime, the company undertook reconstruction, and after about a year of work, the second Tsutenkaku Tower, standing 103 m tall, was completed.

Constructed the Tsutenkaku Tower. Built the iconic Osaka landmark Tsutenkaku Tower. Responding to the enthusiasm of the local Shinsekai residents who wished for the tower's revival after it was dismantled during wartime, the reconstruction was undertaken. After about a year of intensive work, the "Second Tsutenkaku Tower" standing 103 meters tall was completed.

By working honestly and delivering good work, the project was completed in just over two years and three months. The following year, the Construction Association Award was received.

Won the contract for the Nara Prefectural Government Building. The construction period lasted a little over two years and three months, and it was completed in March 1965. In October of the following year, Okumura Group received its first "Building Industry Association (BCS) Award."

Won the "Nara Prefectural Office Building Construction Project." After the bid was awarded, Tahei Okumura instructed, "Do good work sincerely, and do not let people say that the Okumura Group could not do it well." The construction period of 2 years and 3 months saw the completion of the Nara Prefectural Office Building in March 1965. In October of the following year, the company received its first "Building Industry Association (BCS) Award."

The Nara Prefectural Government Building was completed.

Developed Japan's first mud-water shield method "OCMS Method." On April 19, 1968, the patent for the shield method's excavation device, which had been pending, was confirmed, and Patent No. 516245 was registered. The shield method, which is economical, safe, and can be constructed in a short time, also contributed to noise reduction and urban beautification, rapidly expanding to cities nationwide.

The Nara Prefectural Office was completed, and Okumura Group received its first Construction Association Award.

The patent for Japan's first mud-water shield method, the OCMS method, was confirmed. It was expanded nationwide as an economical and safe construction method.

Developed Japan's first mud-water shield method, the "OCMS method." After the patent was confirmed, it expanded nationwide as an economical and safe shield method.

On April 19, 1968, the patent for the shield method excavation device, which had been pending, was confirmed, and Patent No. 516245 was registered.

Research on seismic isolation began, and the seismic isolation system was put into practical use. The Okumura Group Research Institute Management Building was completed as a seismic isolation building, becoming a pioneer in seismic isolation.

Completed the management building of Okumura Group's Research Institute, the first practical anti-seismic building in Japan, becoming a pioneer in seismic isolation.

Completed Japan's first practical seismic isolation building. In 1980, research into seismic isolation began. When news spread that Okumura Group would build a practical seismic isolation building, attention to seismic isolation suddenly increased, and major companies subsequently entered the market. In 1986, Okumura Group completed the "Okumura Group Technology Research Institute Management Building," Japan's first practical seismic isolation building, becoming a pioneer in seismic isolation.

In 1986, the Okumura Group Technical Research Institute's management building became Japan's first practical seismic‑isolated building, pioneering seismic isolation.

The world's first seismic isolation display case for a national treasure was delivered to the Nara National Museum.

The seismic isolation display case delivered to the Nara National Museum demonstrated the world's first use of seismic isolation technology.

World's first seismic isolation display case for a national treasure. Delivered to the Nara National Museum.

The world's first seismic isolation device for lighthouse lenses was developed.

Developed and introduced the world's first seismic isolation device for lighthouse lenses.

World's first seismic isolation device for lighthouse lenses. Seismic isolation device for lighthouse lenses.

A method that excavates the entire cross-section at once was adopted, achieving rapid construction of long inclined shafts.

Pierced with a full-section inclined shaft TBM. As a world-first attempt, a long inclined shaft was constructed in a short period and economically.

World's first full-section TBM through a slanted tunnel. To construct a long slanted tunnel quickly and economically, the first attempt worldwide was made to excavate the entire cross-section at once using a TBM.

Received the Japan Society of Civil Engineers Technical Award and the Nikken Ren Award for Civil Engineering.

A building that combined timber without adhesive contributed to the utilization of timber resources and revitalization of forest resources, receiving many awards.

The "Mie Prefectural Kumanogokudo Center" was completed. It was evaluated as a building that contributes to the utilization of timber resources and the revitalization of forest resources, winning awards such as the 13th Public Building Award.

Ansei River Basin Sewage and Seawater Sewage Main Line, Settsu Takatsuki.

The 100th anniversary of the founding was celebrated with the opening of the Okumura Memorial Hall in Nara.

Celebrated its 100th anniversary and opened the "Okumura Memorial Hall" in Nara.

Expressed gratitude for reaching the 100th anniversary by opening the "Okumura Memorial Hall" in the deeply connected Nara region.

Technology to cancel noise from construction and industrial machinery was developed and featured in Nikkei Technology Outlook 2020.

Developed "Active Noise Cancellation Technology." The technology, which eliminates noise from construction and industrial machinery, attracted attention and was featured in Nikkei Technology Outlook 2020.

Developed "Active Noise Cancellation Technology." Developed technology that cancels noise from construction and industrial machinery by emitting sound from speakers. Featured in "Nikkei Technology Outlook 2020: 100 Technologies That Will Change the World" (Nikkei BP).

In the Okumura Group Technology Research Institute Management Building, the seismic isolation performance 30 years after completion was confirmed through experiments. To widely showcase the technical strength as a "seismic isolation pioneer," the experiment was released to the media and a full-page advertisement was placed in the Nikkei Shimbun. The 30-year research results were recognized with the Japan Seismic Isolation Structure Association Award "Popularization Award."

The seismic isolation performance of the Seismic Isolation Research Institute Management Building was confirmed through experiments, and it was promoted in media and advertising. The Japan Seismic Structure Association Award was received.

Confirmed the seismic isolation performance through experiments, verifying the performance 30 years after completion. Received the Japan Seismic Isolation Structure Association Award "Popularization Award."

A new indoor environment testing building was constructed and the management building was converted to a ZEB, improving the facility's functionality.

Renovated the research institute's experimental facilities. A new indoor environment experimental building was established, and the management building was retrofitted to ZEB (Zero Energy Building).

Major renewal of the research institute's experimental facilities. A new indoor environmental experiment building was constructed, and the management building was renovated to ZEB, significantly improving the functionality of the existing experimental facilities.

Constructed the Ooguro-no-Mori Junior High School in Ryugasaki City using timber, receiving the Prime Minister's Award.

Constructed the "Ryukyu City Ooguro Forest Junior High School" in a wooden building. Adopted new technologies such as the high-strength Matsumoto seismic wall and received the "Prime Minister's Award."

Realizing a circular society with wooden construction. Constructed the "Ryukyu City Ooguro Forest Junior High School" in a wooden building. Utilizing locally sourced timber and adopting new technologies such as the high-strength Matsumoto seismic wall, the school was recognized as a high-functionality, high-design building and received the Prime Minister's Award at the 2022 Wood Utilization Excellence Facility Competition (hosted by the Central Council for Wood Utilization Promotion).

Opened the "Cross Innovation Center" in Marunouchi, Tokyo.

"Cross Innovation Center" opened in Marunouchi, Tokyo. In October 2023, a new office "Cross Innovation Center" (commonly known as Cross AI) was opened in Marunouchi as a hub for cross-field interaction and collaboration among technologists from industry, government, academia, and the private sector.

Opened a new office in Marunouchi, Tokyo, as a hub for interaction among industry, government, academia, and the public.

In October 2023, a new office "Cross Innovation Center" (commonly known as Cross AI) was opened in Marunouchi, Tokyo as a hub for cross‑field interaction and collaboration among technologists from industry, government, academia, and the private sector.

Responsible for the construction of the "Gas Pavilion" and "NTT Pavilion" at the Osaka Kansai Expo.

Celebrating the 120th anniversary of its founding in 2027. Building on its history, we will continue to challenge ourselves to create value for the next era.