| 1914-12 |
Constructed the Asano Slate factory in Tokyo Shinkawa and produced the first slate in Japan (establishment of Asano Slate Co., Ltd.) |
| 1914-12 |
Built Asano Slate factory in Tokyo Shinkawa and manufactured Japan's first slate (established Asano Slate Co., Ltd.) |
| 1923-10 |
Merged with Asano Cement Co., Ltd., becoming its slate division |
| 1923-10 |
Merged with Asano Cement Co., Ltd., becoming its slate division |
| 1924-03 |
Established Asahi Slate Co., Ltd. in Kanagawa-ku, Yokohama (founding of Asahi Asbestos Industry Co., Ltd.) |
| 1924-03 |
March 1924 (Taisho 13) |
| 1924-03 |
Founded |
| 1924-03 |
Established Asahi Slate Co., Ltd. in Kanagawa-ku, Yokohama (established Asahi Asbestos Industry Co., Ltd.) |
| 1924-03 |
Founded: March 1924 (Taisho 13). |
| 1944-03 |
Opened Asahi Slate Co., Ltd.'s Yamanashi factory |
| 1944-03 |
Asahi Slate Co., Ltd. Yamanashi factory opening |
| 1944-03 |
Asahi Slate Co., Ltd. Yamanashi factory opening |
| 1949-05 |
Asahi Slate Co., Ltd. listed its shares on the Tokyo Stock Exchange |
| 1949-05 |
Asahi Slate Co., Ltd. listed on the Tokyo Stock Exchange |
| 1949-05 |
Asahi Slate Co., Ltd. listed on the Tokyo Stock Exchange |
| 1950-12 |
Changed its name to Asahi Asbestos Industry Co., Ltd. and moved its headquarters to Chuo-ku, Tokyo |
| 1950-12 |
Changed name to Asahi Asbestos Industry Co., Ltd. and moved headquarters to Chuo-ku, Tokyo |
| 1951-05 |
Independently established Asano Slate Co., Ltd. from Nihon Cement Co., Ltd. (formerly Asano Cement) |
| 1951-05 |
Independently established Asano Slate Co., Ltd. from Japan Cement Co., Ltd. (formerly Asano Cement) |
| 1951-10 |
Changed its name to Asano Slate Co., Ltd. |
| 1951-10 |
Changed name to Asano Slate Co., Ltd. |
| 1960-07 |
Established Kanto Asano Pipe Co., Ltd. |
| 1960-07 |
Established Kanto Asano Pipe Co., Ltd. |
| 1962-01 |
Opened Asano Slate Co., Ltd.'s Osaka factory |
| 1962-01 |
Asano Slate Co., Ltd. Osaka factory opening |
| 1962-01 |
Asano Slate Co., Ltd. Osaka factory opening |
| 1962-10 |
Asano Slate Co., Ltd. listed its shares on the Second Section of the Tokyo Stock Exchange |
| 1962-10 |
Asano Slate Co., Ltd. listed on the Second Section of the Tokyo Stock Exchange |
| 1962-10 |
Asano Slate Co., Ltd. listed on the Second Section of the Tokyo Stock Exchange |
| 1964-07 |
Established Asahi Silica Industry Co., Ltd. |
| 1964-07 |
Founded Asahi Silica Industry Co., Ltd. |
| 1975-11 |
Opened Asano Slate Co., Ltd. Ibaraki Plant |
| 1975-11 |
Asano Slate Co., Ltd. Ibaraki factory opening |
| 1975-11 |
Opened Asano Slate Co., Ltd. Ibaraki Plant |
| 1987-04 |
Changed the name of Asahi Asbestos Industry Co., Ltd. to Asku Co., Ltd. |
| 1987-04 |
Renamed Asahi Asbestos Industry Co., Ltd. to Asku Co., Ltd. |
| 1989-01 |
Moved headquarters to Tsurumi-ku, Yokohama City |
| 1989-01 |
Moved headquarters to Tsurumi-ku, Yokohama City |
| 1989-11 |
Established Asku Sanshin Engineering Co., Ltd. |
| 1989-11 |
Founded Asku Sanshin Engineering Co., Ltd. |
| 1991-05 |
Divested the Yamanashi plant and established Asku Technica Co., Ltd. |
| 1991-05 |
Divested the Yamanashi plant and founded Asku Technica Co., Ltd. |
| 1999-02 |
AP Connector Division and Shiga Plant obtained ISO 9001 |
| 1999-02 |
AP Connector Division and Shiga Plant obtained ISO 9001. |
| 1999-12 |
Osaka Plant obtained ISO 9001 |
| 1999-12 |
Osaka Plant obtained ISO 9001. |
| 2000-10 |
Asku Co., Ltd. and Asano Slate Co., Ltd. merged to form A&A Materials Co., Ltd., with headquarters in Minato-ku, Tokyo. |
| 2000-10 |
October 2000 merger (Heisei 12) |
| 2000-10 |
Merged in October 2000 |
| 2000-10 |
Asku Co., Ltd. and Asano Slate Co., Ltd. merged to form A&A Materials Co., Ltd., with headquarters in Minato-ku, Tokyo. |
| 2000-10 |
Merged in October 2000 (Heisei 12). |
| 2001-02 |
Ibaraki Plant obtained ISO 9001 |
| 2001-02 |
Ibaraki Plant obtained ISO 9001. |
| 2002-06 |
Moved headquarters to Tsurumi-ku, Yokohama City, Kanagawa Prefecture |
| 2002-06 |
Moved headquarters to Tsurumi-ku, Yokohama City, Kanagawa Prefecture. |
| 2004-03 |
Divested the Ibaraki and Osaka plants and established A&A Ibaraki Co., Ltd. and A&A Osaka Co., Ltd. |
| 2004-03 |
Divested Ibaraki and Osaka plants, establishing A&A Ibaraki Co., Ltd. and A&A Osaka Co., Ltd. |
| 2005-01 |
A&A Ibaraki and the Technology Development Institute obtained ISO 14001 |
| 2005-01 |
A&A Ibaraki and the Technology Development Institute obtained ISO 14001. |
| 2006-02 |
A&A Osaka obtained ISO 14001 |
| 2006-02 |
A&A Osaka obtained ISO 14001. |
| 2009-02 |
Established A&A Construction Co., Ltd. through a corporate split of the construction contracting business |
| 2009-02 |
Established A&A Construction Co., Ltd. through a corporate split of construction contracting. |
| 2024-10 |
Made Daisho Showa Uniboard Co., Ltd. a subsidiary |
| 2024-10 |
Made Daisho Showa Uniboard Co., Ltd. a subsidiary. |
| 2025-02 |
Moved headquarters to Minato-ku, Tokyo; changed the name of A&A Construction Co., Ltd. to A&A Crest Co., Ltd.; changed the name of Daisho Showa Uniboard Co., Ltd. to Uniboard Co., Ltd. |
| 2025-02 |
Moved headquarters to Minato-ku, Tokyo; changed the name of A&A Construction Co., Ltd. to A&A Crest Co., Ltd.; changed the name of Taisho Show UniBoard Co., Ltd. to UniBoard Co., Ltd. |
| 2025-02 |
Moved headquarters to Minato-ku, Tokyo; renamed A&A Construction Co., Ltd. to A&A Crest Co., Ltd.; renamed Daisho Showa Uniboard Co., Ltd. to Uniboard Co., Ltd. |
| 2025-04 |
Made DIC Decol Co., Ltd. a subsidiary; changed the name of DIC Decol Co., Ltd. to Decol Co., Ltd. |
| 2025-04 |
Made DIC Decol Co., Ltd. a subsidiary and changed its name to Decol Co., Ltd. |
| 2025-04 |
Made DIC Decol Co., Ltd. a subsidiary; renamed DIC Decol Co., Ltd. to Decol Co., Ltd. |
