| 1950-05 |
Founded Daido Heat Treatment Industry at 359 Yukekaya-cho, Ota-ku. |
| 1951-08 |
Established Ooya Heat Treatment Co., Ltd. |
| 1951-08-04 |
Established on August 4, 1951 (Showa 26). |
| 1951-08-04 |
Established. |
| 1952-03 |
Designated as a certified factory for Ministry of International Trade and Industry (MITI) inspected tools. |
| 1953-04 |
Commenced operations of the high-frequency hardening division. |
| 1954-03 |
Relocated to 2-18-12 Nakaiikejo, Ota-ku. |
| 1958-12 |
Initiated transition from solid carburizing to gas carburizing method (fully converted by October Showa 40). |
| 1961-04 |
Received research subsidy from MITI and conducted "Research on gas carburizing at high temperatures", presenting results on March 20, Showa 37. |
| 1967-06 |
Acquired factory land in Kanagawa Prefecture Inland Industrial Complex. |
| 1968-04 |
Commenced operations of the Atsugi plant. |
| 1969-05 |
Acquired factory land in Kita-Saitama District, Saitama Prefecture. |
| 1969-09 |
Commenced operations of the Kishi plant. |
| 1971-04 |
Established a laboratory and appointed full-time researchers to commence technology development. |
| 1971-04 |
Established a laboratory for research and development of metal heat treatment technology (now: Technology Research Institute). |
| 1972-01 |
Established Ooya Transportation Co., Ltd. (now O'NeX Line Co., Ltd.). |
| 1973-03 |
Relocated headquarters to 2-14-5 Nakaiikejo, Ota-ku. |
| 1973-12 |
Acquired factory land in Yamaguchi Prefecture, Atsuya-gun, Yōyō-cho. |
| 1974-09 |
Established a lightweight alloy department at the Atsugi plant and commenced heat treatment of non-ferrous metals. |
| 1975-01 |
Participated as capital in an investment development company. |
| 1975-04 |
The laboratory becomes a research institute. |
| 1976-09 |
Yamaguchi factory begins operations. |
| 1976-10 |
The headquarters relocated to 3012-3 Kami-no-hara, Kami-ichi, Atsugi City, Kanagawa Prefecture. |
| 1978-06 |
Established Daoya Giken Co., Ltd. (now ONEX Engineering Co., Ltd.). |
| 1978-12 |
Acquired factory land in Higashimatsuyama Industrial Complex, Saitama Prefecture. |
| 1980-07 |
Higashimatsuyama factory begins operations. |
| 1984-10 |
Yamaguchi factory was spun off and established as new company Sanyo Daoya Heat Treatment Co., Ltd. (now ONEX Yamaguchi Factory). |
| 1985-12 |
The head office factory becomes a JIS-approved factory. |
| 1986-01 |
Installed ONEX Fine Coating equipment at the head office factory and began operations. |
| 1986-01 |
Acquired factory land in Ueda City, Nagano Prefecture. |
| 1986-12 |
Higashimatsuyama factory becomes a JIS-approved factory. |
| 1987-11 |
Participated in capital of Shinano Metallurgical Chemical Co., Ltd. and renamed the company to Nagano Daoya Heat Treatment Co., Ltd. (later ONEX Nagano Co., Ltd.). |
| 1989-08 |
Moved all equipment from Kishi factory to Higashimatsuyama factory and merged. |
| 1991-07 |
Conducted CI including affiliated companies and changed the company name from Daoya Heat Treatment Co., Ltd. to ONEX Co., Ltd. |
| 1991-10 |
Moved ONEX Nagano (now Nagano Factory) to the Shiota Industrial Complex in Ueda City, Nagano Prefecture. |
| 1992-06 |
Conducted a third-party allotment at market value capital increase. |
| 1994-05 |
Established the Koki division at the second factory and began operations. |
| 1997-02 |
Listed shares on the over-the-counter market. |
| 1998-10 |
ONEX Yamaguchi (now Yamaguchi Factory) obtained ISO 9002 certification. |
| 2000-03 |
Dissolved ONEX Nagano and established a new Nagano Factory. |
| 2000-08 |
The Higashimatsuyama plant obtained ISO 9002 certification. |
| 2000-12 |
The Atsugi plant obtained ISO 9002 certification. |
| 2002-05 |
The head office plant and the second plant merged to become the Atsugi plant. |
| 2004-01 |
Acquired and merged with O'NeXx Yamaguchi Co., Ltd., forming the Yamaguchi plant. |
| 2005-04 |
The Atsugi plant obtained ISO 14001 certification. |
| 2005-09 |
The Higashimatsuyama plant obtained ISO 14001 certification. |
| 2006-04 |
The Nagano plant obtained ISO 9001 certification. |
| 2006-07 |
Acquired factory land in the Shin-Yamanoi Industrial Complex, Yanoita City, Yamaguchi Prefecture. |
| 2007-02 |
The second Yamaguchi plant commenced operations. |
| 2010-04 |
Listed on the Osaka Stock Exchange JASDAQ market following the merger of the JASDAQ Stock Exchange and the Osaka Stock Exchange. |
| 2013-07 |
Listed on the Tokyo Stock Exchange JASDAQ market following the market integration of the Osaka Stock Exchange and the Tokyo Stock Exchange. |
| 2013-12 |
Obtained ISO/TS 16949 certification for the Atsugi and Higashimatsuyama plants from Bureau Veritas (BVQI), a quality management system standard for the automotive industry. |
| 2014-05 |
Established O'NeXx Tech Center Inc. |
| 2015-09 |
Obtained JIS Q 9100:2009 certification for the vacuum division of the Atsugi plant from Bureau Veritas (BVQI). |
| 2015-12 |
The Mie plant of O'NeXx Tech Center Inc. commenced operations. |
| 2015-12 |
Established O'NeXx Mie Sales Office. |
| 2016-03 |
Established O'NeXx Line Mie Sales Office. |
| 2017-12 |
Moved part of the headquarters functions to 4F, Daiju Seimei Machida Building, 1-7-23 Morino, Machida City, Tokyo. |
| 2021-03 |
Closed the Nagano plant. |
| 2022-04 |
Transitioned to the Standard market due to a change in the Tokyo Stock Exchange market classification. |
| 2022-07 |
The IATF16949 certification for the Atsugi and Higashimatsuyama factories was withdrawn. |
| 2026-03 |
Moved to the Tamachi main office. |
