| 1922-02 |
Founded as YamaKa Trading, a provider of lighting and power equipment as well as transmission and distribution construction, at the former Osaka Shosen Building in front of Tokyo Yaesu Exit. |
| 1948-09 |
Changed trade name to YamaKa Electric Industry Co., Ltd. |
| 1948-09 |
Changed the trade name to "Yamaka Electric Co., Ltd." |
| 1949-10 |
Established Sendai Sales Office (now Tohoku Transmission Business Headquarters) |
| 1949-10 |
Established Sendai Sales Office (currently Tohoku Power Transmission Business Division). |
| 1950-03 |
Began construction of Japan's first 275,000-volt transmission line, Hokuriku trunk line project. |
| 1950-03 |
Laid the foundation for Japan's first 275kV power transmission line construction project, Hokuriku Main Line Project. |
| 1958-07 |
Established Nagoya Sales Office (now Chubu Transmission Business Division) |
| 1958-07 |
Established Nagoya Sales Office (currently Chubu Power Transmission Business Division). |
| 1959-03 |
Established Osaka Sales Office (now Solution Business Division (Kansai)) |
| 1959-03 |
Established Osaka Sales Office (currently Solution Business Division (Kansai)). |
| 1961-05 |
Received an order for the construction of a transmission line between Danim Saigon in the former Republic of South Vietnam, marking Japan's first overseas expansion as an electrical contractor. |
| 1961-05 |
Received an order for the construction of a power transmission line between Danimoo Saigon in the then Republic of South Vietnam, marking Japan's first overseas expansion as an electrical contractor. |
| 1965-06 |
Received an order for Tokyo Electric Power Company's Boso Line project, which attracted attention as Japan's first 500,000-volt transmission line. |
| 1974-12 |
Received an order for new transmission line construction related to the Mekong River development project in Laos, as well as wiring within Vientiane City and the construction and renovation of various substations. |
| 1974-12 |
Received an order for the construction of new transmission lines associated with the Mekong River development project in Laos, as well as wiring within Vientiane City, and the construction and renovation of various substations. |
| 1976-09 |
Received an order from Iran for the construction of a 12-line, 900 km total length transmission line. |
| 1976-09 |
Received an order for the construction of a 12-line, 900 km total length power transmission line from Iran. |
| 1986-06 |
Received an order for Tokyo Electric Power Company's Boso Line Project, which was noted as Japan's first 500kV power transmission line. |
| 1986-08 |
Received an order for optical fiber construction from domestic power companies, promoting technological development to support the telecommunications industry. |
| 1986-08 |
Received an order for fiber optic construction work from domestic electric power companies, promoting technological development to support the telecommunications and information industry. |
| 1988-10 |
Received an order for Japan's first 1,000,000-volt transmission line construction (Gunma-Yamanashi trunk line). |
| 1991-10 |
Won the contract for Japan's first 1,000,000-volt transmission line construction (Gunma-Yamanashi main line). |
| 1991-10 |
Won the first 1,000 kV transmission line construction project in Japan (Gunma‑Yamanashi main line). |
| 1994-10 |
Continued to receive orders for 1,000,000-volt transmission line construction (Minami Iwaki trunk line). |
| 1994-10 |
Also secured the contract for a 1,000,000-volt transmission line construction (Minami-Iwaki main line). |
| 1994-10 |
Continued to win 1,000 kV transmission line construction projects (Minami‑Iwaki main line). |
| 1995-02 |
Listed on the Japan Securities Dealers Association (now Tokyo Stock Exchange JASDAQ Market) and increased capital to 742.55 million yen. |
| 1996-02 |
Listed shares on the Japan Securities Association (now Tokyo Stock Exchange JASDAQ market) and increased capital to 742.55 million yen. |
| 1996-12 |
Established the Development Division (now Electric Power Infrastructure Business Headquarters). |
| 1998-03 |
Increased capital to 830.06 million yen. |
| 2006-05 |
Increased capital to 998.66 million yen |
| 2006-10 |
Listed shares on the Japan Securities Association (now Tokyo Stock Exchange JASDAQ market) and increased capital to 742.55 million yen. |
| 2006-10 |
Established the Development Division (now Power Infrastructure Business Division). |
| 2008-07 |
Established Ishinomaki Sales Office in Ishinomaki City, Miyagi Prefecture |
| 2008-12 |
Established the Development Division (now Power Infrastructure Business Division). |
| 2008-12 |
Increased capital to 823.06 million yen. |
| 2009-02 |
Dispatch of supervisor for power transmission line construction in Dar es Salaam, United Republic of Tanzania |
| 2010-03 |
Increased capital to 823.06 million yen. |
| 2010-08 |
Newly established equipment center in Zao Town, Miyagi Prefecture |
| 2010-08 |
Established an equipment center in Zao Town, Miyagi Prefecture. |
| 2011-02 |
Established the Ishinomaki branch office in Ishinomaki City, Miyagi Prefecture. |
| 2012-02 |
Made Tokyo Management Co., Ltd., which conducts building management business, a 100% subsidiary |
| 2012-02 |
Made Tokyo Management Co., Ltd., a building management company, a 100% subsidiary. |
| 2012-12 |
Relocated headquarters to Toshima Ward, Tokyo |
| 2012-12 |
Moved headquarters to Toshima Ward, Tokyo. |
| 2013-08 |
Developed the tower raising device "Enark 160" |
| 2013-08 |
Developed the tower-lifting device 'Enark 160'. |
| 2014-09 |
Signed supervisor contract and carried out work related to main transmission line construction in Myanmar |
| 2014-09 |
Signed a supervisory contract for core transmission line construction in Myanmar and carried out the work. |
| 2015-12 |
Received order from LG CNS Japan Co., Ltd. for large-scale solar construction work of 30MW (Fukushima Prefecture) |
| 2015-12 |
Won a 30 MW large-scale solar construction contract from LG CNS Japan (Fukushima Prefecture). |
| 2016-06 |
Received order from Canadian Solar Project Co., Ltd. for high-difficulty construction work on the Saitama Minano Power Plant on a steep slope with a maximum gradient of 45 degrees |
| 2016-06 |
Won the construction contract for the Saitama Minano Power Plant, a high-difficulty project on a steep slope of up to 45 degrees, from Canadian Solar Project Co., Ltd. |
| 2016-08 |
Acquired patent rights for tower raising device "Enark 160" |
| 2016-08 |
Obtained the patent rights for the tower-lifting device 'Enark 160'. |
| 2017-08 |
Relocated Sendai Power Transmission Department (now Tohoku Power Transmission Business Division) to Aoba Ward, Sendai City, Miyagi Prefecture |
| 2017-08 |
Moved the Sendai Transmission Division (now Tohoku Transmission Business Division) to Chuo, Aoba Ward, Sendai City, Miyagi Prefecture. |
| 2017-12 |
Changed trade name to "ETS Holdings Co., Ltd." |
| 2017-12 |
Changed the company name to 'ETS Holdings Inc.'. |
| 2018-02 |
Signed partnership agreement with General Incorporated Association for Disabled Persons' Self-Reliance Support Organization |
| 2018-02 |
Signed a partnership agreement with the General Incorporated Association Disability Self-Help Support Organization. |
| 2018-05 |
Increased capital to 996.66 million yen. |
| 2019-05 |
Signed business alliance agreement with Navic Co., Ltd. |
| 2019-05 |
Signed a business alliance agreement with Navick Co., Ltd. |
| 2019-06 |
Completed construction of special high-voltage substation for 154,000 volts at 55MW solar power plant (Gifu Prefecture) |
| 2019-06 |
Completed the special high-voltage substation construction (154,000 volts) for a 55 MW solar power plant (Gifu Prefecture). |
| 2019-09 |
Relocated Kansai Sales Office to Higashikora Bridge, Chuo Ward, Osaka City |
| 2019-09 |
Completed the special high‑voltage substation construction for receiving 154 kV at a 62 MW solar power plant (Aichi Prefecture). |
| 2019-10 |
Relocated Chubu Power Transmission Business Division to Kiyosu Ward, Nagoya City, Aichi Prefecture |
| 2019-11 |
Completed construction of special high-voltage substation for 154,000 volts at 62MW solar power plant (Aichi Prefecture) |
| 2020-03 |
Entered into a business partnership with Sunlit Seedlings Co., Ltd., a Kyoto University‑originated venture company that conducts ecosystem surveys, etc. (Kyoto Prefecture). |
| 2020-10 |
Entered into a business partnership with Sunlit Seedlings Co., Ltd., a Kyoto University‑originated venture company that conducts ecosystem surveys, etc. (Kyoto Prefecture). |
| 2021-02 |
Made Iwai Industrial Co., Ltd. a 100% subsidiary. |
| 2021-06 |
Formed business alliance with Sunlit Seed Links Co., Ltd., a Kyoto University venture company engaged in ecosystem surveys and other activities |
| 2021-08 |
Ukihashi Solar Power Plant (Ukihashi City, Fukuoka Prefecture) acquired |
| 2021-08 |
Acquired the Ukiha Solar Power Plant (Ukiha City, Fukuoka Prefecture). |
| 2021-09 |
Iwai Industries Co., Ltd. became a 100% subsidiary |
| 2021-09 |
Made Iwai Industrial Co., Ltd. a 100% subsidiary. |
| 2021-12 |
Yuki Industries Co., Ltd. became a 100% subsidiary |
| 2021-12 |
Made Yuuki Industry Co., Ltd. a 100% subsidiary. |
| 2022-02 |
100th anniversary of founding |
| 2022-02 |
Celebrated 100th anniversary of founding. |
| 2022-06 |
Chuo Electric Construction Co., Ltd. became a 100% subsidiary |
| 2022-06 |
Made Chuo Electric Construction Co., Ltd. a 100% subsidiary. |
| 2022-10 |
Chuo Electric Construction Co., Ltd. merged with its subsidiary Denyusha Co., Ltd. and changed its name to DC Line Co., Ltd. |
| 2023-10 |
Chuo Electric Construction Co., Ltd. merged with its subsidiary Denyu-sha Co., Ltd. and changed its name to DC Line Co., Ltd. |
| 2023-10 |
Established the company through a share transfer. |
| 2023-10 |
Changed the corporate name from ETS Holdings Co., Ltd. to ETS Line Co., Ltd. |
| 2023-10 |
Changed the corporate name from Tokyo Management Co., Ltd. to ETSOK Co., Ltd. |
| 2023-10 |
Changed the corporate name from Yuuki Industry Co., Ltd. to ETS Clear Co., Ltd. |
| 2024-10 |
Established through share transfer |
| 2025-10 |
Changed the trade name from "ETS Holdings Co., Ltd." to "ETS Line Co., Ltd." |
| 2025-10 |
Changed the trade name from "Tokyo Management Co., Ltd." to "ETSOK Co., Ltd." |
| 2025-10 |
Changed the trade name from "Yuki Industries Co., Ltd." to "ETS Clear Co., Ltd." |
