| 1959-11 |
In November of Showa 34 (1959), established as Nanshin High-Pressure Concrete Co., Ltd. with capital of 10 million yen in Korimoto Town, Kagoshima City, for the purpose of manufacturing and selling concrete products, designing and constructing works, and PC bridge construction business. |
| 1959-11 |
Established Nankoku High‑Pressure Concrete Co., Ltd. with a capital of 10 million yen in Kagoshima City, Gunto‑machi, for the purpose of manufacturing and selling concrete products, as well as designing and constructing projects and PC bridge construction. At the time of establishment, the company acquired the Kawauchi factory in Kawauchi City, Gunto‑machi, Kagoshima Prefecture; the Tōjo factory in Miyazaki City, Ichijō‑machi, Miyazaki Prefecture; and the Kumamoto factory in Uto City, Sanjō‑machi, Kumamoto Prefecture from Oevamura Group Co., Ltd. (Current address: Matsubashi‑cho, Uji City, Kumamoto Prefecture). Established the Kumamoto branch office in Sanjō‑machi, Uto City, Kumamoto Prefecture. (Current address: Higashi‑ku, Kumamoto City, Kumamoto Prefecture). |
| 1960-04 |
Completed registration as Construction Business Law registration (T) No. 2685 by the Minister of Construction in April of Showa 35 (1960). |
| 1960-04 |
Completed registration No. 2685 with the Minister of Construction under the Construction Business Act. (Registration will be renewed every two years thereafter.) |
| 1961-11 |
In November of Showa 36 (1961), established Fukuoka Sales Office (now Fukuoka Branch) in Fukuoka City, Fukuoka Prefecture. |
| 1961-11 |
Established the Fukuoka branch office (currently Fukuoka Branch) in Fukuoka City, Fukuoka Prefecture. (Current address: Chuo Ward, Fukuoka City). |
| 1969-11 |
Established a subsidiary Minami Nihon Foundation Industry Co., Ltd. for pile driving work. |
| 1970-11 |
In November of Showa 44 (1969), established a subsidiary, Nanshin Foundation Engineering Co., Ltd., for pile driving works. |
| 1973-10 |
In October 1973, following amendments to the Construction Business Act, obtained construction minister permits (Special 48) No. 1821 (Civil Engineering) and (General 48) No. 1821 (Scaffolding and Earthwork), and expanded operations into the construction division. |
| 1973-10 |
In response to amendments to the Construction Business Act, obtained construction minister permits (T-48) No. 1821 (civil engineering work) and (General-48) No. 1821 (scaffold and earthwork construction), and aims to strengthen business expansion into construction departments. (Permits renewed every 3 years thereafter) |
| 1974-07 |
Established Miyazaki Sales Office in Miyazaki City, Miyazaki Prefecture. |
| 1975-02 |
In February 1975, relocated the head office to Ijiki Town, Kagoshima City. |
| 1975-02 |
Relocated headquarters to Ijiki Town, Kagoshima City. |
| 1978-01 |
In July 1974, established the Miyazaki Sales Office in Miyazaki City, Miyazaki Prefecture. |
| 1978-01 |
Established Tokyo Office (currently Tokyo Branch) in Minato Ward, Tokyo. |
| 1980-01 |
In January 1981, established the Tokyo Office (now Tokyo Branch) in Minato Ward, Tokyo. |
| 1983-10 |
In October 1983, established the Okinawa Sales Office in Naha City, Okinawa Prefecture. |
| 1983-10 |
Established Okinawa Sales Office in Naha City, Okinawa Prefecture. (Current address: Urasoe City, Okinawa Prefecture) |
| 1985-08 |
In August 1985, opened the Osumi Factory in Takayama Town, Kimotsuki District, Kagoshima Prefecture. |
| 1985-08 |
Opened Osumi Factory in Takayama Town, Kimotsuki District, Kagoshima Prefecture. (Current address: Kimotsuki Town, Kimotsuki District, Kagoshima Prefecture) |
| 1990-01 |
In January 1990, changed the company name to Kotsu Industries Co., Ltd. |
| 1990-01 |
Changed trade name to Kotsu Industry Co., Ltd. |
| 1994-09 |
In September 1994, established the Saga Branch (now Saga Sales Office) in Tosu City, Saga Prefecture. |
| 1994-09 |
Established Saga Branch (currently Saga Sales Office) in Tosu City, Saga Prefecture. (Current address: Saga City, Saga Prefecture) |
| 1994-12 |
In December 1994, established the Nagasaki Branch (now Nagasaki Sales Office) in Nagasaki City, Nagasaki Prefecture. |
| 1994-12 |
Established Nagasaki Branch (currently Nagasaki Sales Office) in Nagasaki City, Nagasaki Prefecture. |
| 1996-12 |
In December 1996, established the Kanoya Sales Office in Kanoya City, Kagoshima Prefecture. |
| 1996-12 |
Established Kanoya Sales Office in Kanoya City, Kagoshima Prefecture. (Current address: Kanoya City, Kimotsuki District, Kagoshima Prefecture) |
| 1997-07 |
In July 1997, completed registration as a construction consultant (Construction 9 No. 5990). |
| 1997-07 |
Completed registration of construction consultant (No. 5990, Ken 9). (Registration renewed every 5 years thereafter) |
| 1997-09 |
In September 1997, established the Yokohama Sales Office in Naka Ward, Yokohama City, Kanagawa Prefecture. |
| 1997-09 |
Established Yokohama Sales Office in Naka Ward, Yokohama City, Kanagawa Prefecture. |
| 1998-04 |
In April 1998, established the Kitakyushu Sales Office in Kokurakita Ward, Kitakyushu City, Fukuoka Prefecture. |
| 1998-04 |
Established Kitakyushu Sales Office in Kokurakita Ward, Kitakyushu City, Fukuoka Prefecture. (Current address: Kokuraminami Ward, Kitakyushu City, Fukuoka Prefecture) |
| 1998-11 |
In November 1998, established a subsidiary, Keitech Corporation, for maintenance and repair of civil engineering and architectural structures. |
| 1998-11 |
Established Kitek Co., Ltd. as a civil engineering and architectural structure maintenance company in November 1998 as a 100% subsidiary of Koatsu Industrial Co., Ltd. |
| 1998-11 |
Established a subsidiary K-Tech Co., Ltd. (currently a consolidated subsidiary) for the purpose of designing and constructing maintenance and repair of civil engineering and architectural structures. |
| 1999-07 |
In July 1999, received approval for stock registration from the Japan Securities Dealers Association. |
| 1999-07 |
Received stock registration approval from the Japan Securities Dealers Association. |
| 1999-10 |
In October 1999, established the Yamaguchi Sales Office in Ogori Town, Yamaguchi District, Yamaguchi Prefecture. |
| 1999-10 |
In October 1999, obtained ISO 9001 certification. |
| 1999-10 |
Established Yamaguchi Sales Office in Ogori Town, Yamaguchi District, Yamaguchi Prefecture. (Current address: Yamaguchi City, Yamaguchi Prefecture) |
| 1999-10 |
Obtained ISO9001 certification. |
| 2001-05 |
In May 2001, listed on the Second Section of the Osaka Securities Exchange and the Fukuoka Securities Exchange. |
| 2001-05 |
Listed on the Osaka Securities Exchange Second Section and Fukuoka Securities Exchange. |
| 2001-10 |
In October 2001, obtained ISO 14001 certification. |
| 2001-10 |
Obtained ISO14001 certification. |
| 2006-04 |
In April 2006, established the Nagoya Sales Office in Kasugai City, Aichi Prefecture. |
| 2006-04 |
Established Nagoya Sales Office in Kasugai City, Aichi Prefecture. (Current address: Kiyosu City, Aichi Prefecture) |
| 2006-07 |
In July 2006, the concrete pile product business was transferred to Koatsu Mitani Sekisan Co., Ltd. |
| 2006-07 |
Transferred concrete pile product business to Koatsu Mitani Sekisan Co., Ltd. (Now: Kagoshima Koatsu Sekisan Co., Ltd.) |
| 2007-10 |
Merged with consolidated subsidiary Minami Nihon Foundation Engineering Co., Ltd. |
| 2012-01 |
In October 2007, the consolidated subsidiary Minami Japan Foundation Industry Co., Ltd. was absorbed and merged. |
| 2012-01 |
Obtained OHSAS18001 certification. (Now: ISO45001) |
| 2013-01 |
In January 2012, obtained OHSAS 18001 certification (currently ISO 45001). |
| 2013-07 |
In July 2013, listed shares on the Second Section of the Tokyo Stock Exchange. |
| 2013-07 |
Listed on the Second Section of the Tokyo Stock Exchange. |
| 2014-02 |
In February 2014, began selling electricity generated from solar power. |
| 2014-02 |
Started selling electricity generated by solar power. |
| 2017-02 |
In February 2017, received the "Kurumin" certification from the Minister of Health, Labour and Welfare as a child-rearing support company. |
| 2017-02 |
Certified as a "Child-rearing Support Company" by the Minister of Health, Labour and Welfare, receiving the "Kurumin" certification. |
| 2017-04 |
In April 2017, established the Ibaraki branch office in Kasama City, Ibaraki Prefecture. |
| 2017-04 |
Established Ibaraki Sales Office in Kasama City, Ibaraki Prefecture. |
| 2017-08 |
In August 2017, commenced operations at the Kumamoto factory (Matsubashi City) in partnership with GaiaTech Co., Ltd. and a limited liability partnership. |
| 2017-08 |
In August 2017, received the "Excellent Construction Performance Company of FY2017" certification from the Ministry of Land, Infrastructure, Transport and Tourism Kyushu Regional Development Bureau. |
| 2017-08 |
Started operations at the Kumamoto Factory (Matsuhashi City) with Gaia Tech Co., Ltd. and a Limited Liability Partnership (LLP). |
| 2017-08 |
Received recognition from the Kyushu Regional Development Bureau of the Ministry of Land, Infrastructure, Transport and Tourism as a "Company with Excellent Construction Performance for FY 2017". Continuing to maintain this recognition. |
| 2017-11 |
In November 2017, joined the "Ikubos Promotion Alliance" in Kagoshima City. |
| 2017-11 |
Joined Kagoshima City "Ikuboss Promotion Alliance". |
| 2018-01 |
In January 2018, established the Kobe branch office in Taumizu Ward, Kobe City, Hyogo Prefecture. |
| 2018-01 |
Established Kobe Sales Office in Tarumi Ward, Kobe City, Hyogo Prefecture. |
| 2020-12 |
In December 2020, received the "Platinum Kurumin" certification from the Minister of Health, Labour and Welfare as a child-rearing support company with high standards. |
| 2020-12 |
Received the "Platinum Kurumin" certification from the Minister of Health, Labour and Welfare for high-level initiatives as a "Child-rearing Support Company". |
| 2021-06 |
In June 2021, registered as a Kagoshima SDGs Promotion Partner and began efforts toward the SDGs. |
| 2021-06 |
Registered as a Kagoshima SDGs Promotion Partner. Started SDGs initiatives. |
| 2021-10 |
In October 2021, expanded the site of the Oshima factory (Kanzaki Town) and established a new office and ready‑mix concrete plant. |
| 2021-10 |
Expanded the site of Osumi Factory (Kimitachi Town) and established an office and ready-mixed concrete plant. |
| 2022-04 |
In April 2022, changed market to the Standard Market following the Tokyo Stock Exchange market reorganization. |
| 2022-04 |
Changed to the Standard Market following the reorganization of the Tokyo Stock Exchange. |
| 2025-11 |
In November 2025, discontinued listing on the Tokyo Stock Exchange and Fukuoka Stock Exchange following the successful takeover bid (TOB). |
| 2025-11 |
Abolished listing on the Tokyo Stock Exchange and Fukuoka Stock Exchange following the completion of a tender offer (TOB). |
