| 1932-12 |
Minoru Okamoto and his sister and two brothers began research on skins made from natural rubber latex |
| 1932-12 |
Minosuke Okamoto, his older sister, and his younger brother began conducting research on condoms made of natural rubber latex |
| 1934-01 |
Founding of Japan Rubber Industry Co., Ltd. |
| 1934-01 |
Nippon Gum Industries, Ltd. established in Togoshi-cho, Ebara-ku, Tokyo |
| 1934-02 |
Founding of Okamoto Rubber Industry Workshop |
| 1934-02 |
Okamoto Rubber Plant established in Azuma-machi, Mukojima-ku, Tokyo |
| 1935-08 |
平井工場（江戸川区平井）開設 |
| 1935-08 |
Hirai Plant opened in Hirai, Edogawa-ku, Tokyo |
| 1936-08 |
Okamoto Rubber Industry Workshop incorporated as "International Rubber Industry Co., Ltd." |
| 1936-08 |
Okamoto Rubber Plant incorporated as Kokusai Gomu Kogyo Kabushiki Kaisha |
| 1937-06 |
Founding of Riken Rubber Industry Co., Ltd. |
| 1937-06 |
Riken Gomu Kogyo Kabushiki Kaisha established in Oji-ku, Tokyo |
| 1943-07 |
Establishment of Ashikaga Factory (Ashikaga City, Tochigi Prefecture) |
| 1943-07 |
Ashikaga Plant opened in Ashikaga-shi, Tochigi Prefecture |
| 1945-03 |
Establishment of former Fukushima Factory (Ogawa Town, Iwaki District, Iwaki County) |
| 1945-03 |
Former Fukushima Plant opened in Takahagi-korojiri, Ogawa-machi, Iwaki-gun |
| 1947-08 |
Rebranding of International Rubber Industry Co., Ltd. to "Okamoto Rubber Industry Co., Ltd." |
| 1947-08 |
Kokusai Gomu Kogyo Kabushiki Kaisha changed its trade name to Okamoto Rubber Co., Ltd. |
| 1949-07 |
Listed on the Tokyo Stock Exchange |
| 1949-07 |
Listed on the Tokyo Stock Exchange |
| 1949-10 |
Rebranding of Riken Rubber Industry Co., Ltd. to "Riken Gomu Co., Ltd." |
| 1949-10 |
Riken Gomu Kogyo Kabushiki Kaisha changed its trade name to Riken Rubber Co., Ltd. |
| 1953-09 |
Establishment of Zebra Bicycle Co., Ltd. (Ginza, Chuo-ku) |
| 1953-09 |
Zebra-Kenko Bicycles Co., Ltd. established in Ginza, Chuo-ku, Tokyo |
| 1958-02 |
Merger of Riken Gomu Co., Ltd. and Japan Rubber Industry Co., Ltd. to "Japan Riken Gomu Co., Ltd." |
| 1958-02 |
Riken Rubber Co., Ltd. and Nippon Gum Industries, Ltd. merged to become Nippon Riken Rubber Co., Ltd. |
| 1958-08 |
大阪出張所開設（大阪市東区糸屋町） |
| 1958-08 |
Osaka Sub-branch Office opened in Itoyamachi, Higashi-ku, Osaka |
| 1961-06 |
Headquarters relocation to Bunkyo Ward, Haruki Town |
| 1961-06 |
Nippon Riken Rubber Co., Ltd. headquarters relocated to Harukicho, Bunkyo-ku, Tokyo |
| 1961-08 |
Establishment of Kanagawa Factory (Zama City, Higashihara) |
| 1961-08 |
Kanagawa Plant opened in Higashihara, Zama-shi, Kanagawa |
| 1961-10 |
Designated as First Section of the Tokyo Stock Exchange |
| 1961-10 |
Assigned to the First Section of the Tokyo Stock Exchange |
| 1963-10 |
Establishment of Hong Kong (British territory) Representative Office |
| 1963-10 |
Representative office opened in British Hong Kong |
| 1964-04 |
Established Gunma Factory (Ota City Uekino) |
| 1964-04 |
Gunma Plant opened in Uekinocho, Ota-shi |
| 1964-05 |
Established Ibaraki Factory (Ryugasaki City Itabashi Town) |
| 1964-05 |
Ibaraki Plant opened in Itabashimachi, Ryugasaki-shi |
| 1965-06 |
Established Fukushima Factory (Taira City Akai) |
| 1965-06 |
Fukushima Plant opened in Akai, Taira-shi |
| 1966-09 |
Completion of Head Office Building |
| 1966-09 |
Completed construction of headquarters building |
| 1968-02 |
Merger of Japan Riken Rubber Co., Ltd. and Okamoto Rubber Industries Co., Ltd. ("Okamoto Riken Rubber Co., Ltd.") |
| 1968-02 |
Nippon Riken Rubber Co., Ltd. and Okamoto Rubber Co., Ltd. merged to become Okamoto Riken Rubber Co., Ltd. |
| 1970-01 |
Zebra Bicycle Co., Ltd. changes trade name to "Zebra Kenko Bicycle Co., Ltd." |
| 1970-01 |
Zebra Bicycles Co., Ltd. changed its trade name to Zebra-Kenko Bicycles Co., Ltd. |
| 1970-04 |
Listed on Osaka Securities Exchange First Section Market |
| 1970-04 |
Listed in the First Section of the Osaka Securities Exchange |
| 1974-01 |
米国子会社（O.M. Inc.）設立 |
| 1974-01 |
Established subsidiary O.M. Inc. in USA |
| 1976-05 |
Okamoto Riken Rubber Co., Ltd. acquires Zebra Kenko Bicycle Co., Ltd. |
| 1976-05 |
Okamoto Riken Rubber Co., Ltd. absorbed Zebra-Kenko Bicycles Co., Ltd. |
| 1981-02 |
Establishment of Okamoto Sewing Co., Ltd. |
| 1981-10 |
Made Fuyo Cycle Co., Ltd. a subsidiary ("Zebra Bicycle Co., Ltd.") |
| 1984-02 |
50th Anniversary of Founding |
| 1984-02 |
50th anniversary of establishment |
| 1985-04 |
Established Shizuoka Factory (Yoshida Town, Haibara District) |
| 1985-04 |
Opened Shizuoka Plant in Yoshida-cho, Haibara-gun |
| 1985-10 |
Okamoto Riken Rubber Co., Ltd. changes trade name to "Okamoto Corporation" |
| 1985-10 |
Okamoto Riken Rubber Co., Ltd. changed its trade name to Okamoto Industries, Inc. |
| 1989-07 |
Established a joint venture with Michelin (Michelin) ("Michelin Okamoto Tire Co., Ltd.") |
| 1989-07 |
Teamed with Michelin to establish the joint venture Michelin Okamoto Tire Corporation |
| 1998-04 |
Established Thai subsidiary (SIAM OKAMOTO Co., Ltd.) |
| 1998-04 |
Established subsidiary SIAM OKAMOTO Co., Ltd. in Thailand |
| 1999-04 |
Established Thai subsidiary (APOLLOTEX CO., LTD.) |
| 1999-08 |
Established subsidiary APOLLOTEX Co., Ltd. in Thailand |
| 2000-03 |
Dissolved business partnership with Michelin and transferred joint venture company shares |
| 2000-03 |
Dissolved business association with Michelin, transferred joint venture |
| 2000-04 |
Acquired Hillson Deck Co., Ltd. as a subsidiary |
| 2000-04 |
Acquired Hillson-Dec Co., Ltd. as a subsidiary |
| 2001-03 |
Acquired Union Royal Co., Ltd. as a subsidiary |
| 2001-03 |
Acquired Union Royal Co., Ltd. as a subsidiary |
| 2002-08 |
Acquired Laminated Film Business |
| 2002-08 |
Acquired laminate film business |
| 2004-04 |
Acquisition of dehumidifier (Water Absorber) business |
| 2004-04 |
Acquired dehumidifier ("Mizutori-zosan") business |
| 2004-05 |
Establishment of Thai subsidiary (OKAMOTO RUBBER PRODUCTS Co., LTD.) |
| 2004-05 |
Established subsidiary OKAMOTO RUBBER PRODUCTS Co., Ltd. in Thailand |
| 2004-08 |
Establishment of Vietnamese subsidiary (OKAMOTO VIETNAM Co., LTD.) |
| 2004-08 |
Established subsidiary OKAMOTO VIETNAM Co., Ltd. in Vietnam |
| 2004-09 |
Made a subsidiary of Sekai Chō Co., Ltd. |
| 2004-09 |
Acquired Secaicho Co., Ltd. as a subsidiary |
| 2004-12 |
Acquisition of decorative film business for building materials |
| 2004-12 |
Acquired decorative films business |
| 2005-03 |
Made Ichijiku Pharmaceutical Co., Ltd. a subsidiary |
| 2005-03 |
Acquired Ichijiku Pharmaceutical Co., Ltd. as a subsidiary |
| 2005-06 |
Acquisition of laminated film (Aromar Film) business |
| 2005-06 |
Acquired laminate film ("allomer film") business |
| 2006-03 |
Acquisition of cockroach extermination agent (Inpirresu) business |
| 2006-03 |
Acquired cockroach insecticide ("INPYRETH") business |
| 2006-08 |
Established Joso Logistics Center (Joso City, Ibaraki Prefecture) |
| 2006-08 |
Opened Joso Distribution Center in Joso-shi, Ibaraki Prefecture |
| 2006-11 |
中国子会社（岡本貿易（深圳）有限公司）設立 |
| 2006-11 |
Established subsidiary Okamoto Industries (Shenzhen) Co., Ltd. in China |
| 2007-04 |
Acquisition of dehydration and water absorption sheet business for food (Pichitto) |
| 2007-04 |
Acquired dehydrant/absorbent sheet for food products ("Pichitto") business via transfer |
| 2007-05 |
Establishment of Vietnamese subsidiary (VINA OKAMOTO Co., LTD.) |
| 2007-05 |
Established subsidiary VINA OKAMOTO Co., Ltd. in Vietnam |
| 2007-07 |
米国子会社（OKAMOTO SANDUSKY Manufacturing L.L.C.）設立 |
| 2007-07 |
Established subsidiary OKAMOTO SANDUSKY Manufacturing L.L.C. in USA |
| 2009-11 |
Established Ushiku Logistics Center (Ushiku City, Ibaraki Prefecture) |
| 2009-11 |
Opened Ushiku Distribution Center in Ushiku-shi, Ibaraki Prefecture |
| 2010-10 |
Merged Sekai Chō (Co., Ltd.) and Union Royal (Co., Ltd.) (Sekai Chō Union Co., Ltd.) |
| 2010-10 |
Secaicho Co., Ltd. and Union Royal Co., Ltd. merged to become Secaicho Union Corporation |
| 2012-01 |
Established Okoyama Logistics Center (Nagi Town, Katsuta District, Okayama Prefecture) |
| 2012-01 |
Opened Okayama Distribution Center in Nagi-cho, Katsuta-gun, Okayama Prefecture |
| 2012-04 |
Made Shobo Rubber Co., Ltd. a subsidiary |
| 2012-04 |
Acquired Funabori Rubber Co., Ltd. as a subsidiary |
| 2013-02 |
Established subsidiary Okamoto Manufacturing（GD）Ltd. in China |
| 2013-06 |
Okamoto Sewing Co., Ltd. changed its trade name to Shoe Tech Okamoto Co., Ltd. |
| 2013-10 |
Commenced business of solar power generation for selling power |
| 2014-02 |
80th Anniversary |
| 2017-09 |
Made Riken Corundum Co., Ltd. a subsidiary |
| 2017-09 |
Acquired Riken Corundum Co., Ltd. as a subsidiary |
| 2018-03 |
Established Tsukuba Factory (Ushiku City, Ibaraki Prefecture) |
| 2019-02 |
85th Anniversary of Founding |
| 2019-02 |
85th anniversary of establishment |
| 2020-10 |
Established Okamoto Environmental Development Co., Ltd. |
| 2024-02 |
90th Anniversary |
