| 1843 |
Organization of terpene information by Otto Bärn (organizing multiple names for the same compound) |
| 1886 |
Bärn proposed the original form of the isoprene rule |
| 1892 |
Discovered the existence of nine types of terpenes |
| 1914 |
Otto Bärn authored 'Terpenes and Camphor' (page 180) |
| 1922 |
Leo Rudzicka systematized the isoprene rule |
| 1947 |
Founded Yasuhara Oil & Fat Factory (Hiroshima Prefecture, Kōnu District, Kōnu Town, now Miji City). Production of terpenes, rosin, and pine tar began. |
| 1947 |
Founded Anayama Oil & Fat Factory (Hiroshima Prefecture, Kōnu District, Kōnu Town, now Sanjii City). Commenced production of terpene, rosin, and pine tar. |
| 1949 |
Mizaki Factory established (closed 2008). |
| 1949 |
Established Mezaki Factory (closed in 2008) |
| 1959 |
Yasuhara Oil & Fat Industry Co., Ltd. established (headquarters in Mizaki-cho, Fuchu-shi, Hiroshima Prefecture). |
| 1959 |
Established Anayama Oil & Fat Industry Co., Ltd. (Headquarters: Mezaki Town, Fuchu City, Hiroshima Prefecture) |
| 1960 |
Kawauchi Factory established (closed 2018). |
| 1960 |
Established Kawauchi Factory (closed in 2018) |
| 1961 |
Takagi Factory established (closed 2020). |
| 1961 |
Established Takagi Factory (closed in 2020) |
| 1962 |
Tokyo Branch Office established (now Tokyo Office). |
| 1962 |
Opened Tokyo Branch Office (now Tokyo Office) |
| 1964 |
Report on terpene biosynthesis by Feodor Lysenko and Konrad Bloch |
| 1964 |
Lysenko's presentation of the biosynthetic pathway from acetate to terpenes and fatty acids |
| 1966 |
Mizaki Factory began production of hot-melt adhesive 'Hirodain'. <Related company: Hirosu Industrial> Hirosu Industrial Co., Ltd. established, transferring hot-melt adhesive business from Yasuhara Oil & Fat Industry. |
| 1966 |
Commenced production of hot-melt adhesive 'Hirodain' at Mezaki Factory. (Related company Hirodain Industry) Established Hirodain Industry Co., Ltd. Transferred hot-melt adhesive business from Anayama Oil & Fat Industry. |
| 1967 |
Headquarters relocated to Takagi-cho, Fuchu-shi, Hiroshima Prefecture. |
| 1967 |
Relocated headquarters (Takagi Town, Fuchu City, Hiroshima Prefecture) |
| 1969 |
Osaka Sales Office established (integrated into Tokyo Office in 2023). |
| 1969 |
Opened Osaka Sales Office (integrated into Tokyo Office in 2023) |
| 1972 |
Research institute established at Takagi Factory. |
| 1977 |
YS Corporation established (commercial division of Yasuhara Oil & Fat Industry and Hirosu Industrial). |
| 1977 |
Established YS Corporation (related company) (Commercial division of Anayama Oil & Fat Industry and Hirodain Industry) |
| 1980 |
Renamed to Hirosu Corporation. |
| 1980 |
Renamed to Hirodain Co., Ltd. (related company YS) |
| 1981 |
Sōryō Factory established (integrated into Ukai Factory in 2023). |
| 1981 |
Established Sumire Factory (related company Hirodain Industry) (integrated into Ukai Factory in 2023) |
| 1984 |
Shin-Ikihama Factory established. |
| 1984 |
New Shin-Ikebashi Factory |
| 1989 |
Renamed to Yasuhara Chemical Co., Ltd. |
| 1995 |
Listed on the Hiroshima Stock Exchange (merged with Tokyo Stock Exchange in 2000). |
| 1996 |
Listed on the Osaka Stock Exchange Second Section (delisted in 2003). |
| 1997 |
Absorbed and merged Hirosu Industrial Co., Ltd. |
| 1999 |
Ukai Factory established. |
| 1999 |
New Ukai Factory |
| 2000 |
Listed on the Tokyo Stock Exchange Second Section |
| 2005 |
Absorbed and merged with Hirodain Co., Ltd. |
| 2007 |
Newly established Fukuyama Factory |
| 2007 |
New Fukuyama Factory |
| 2010 |
Established a research institute at Fukuyama Factory |
| 2017 |
Integrated Takagi Factory into Fukuyama Factory and renamed Takagi Factory to Fukuyama Factory Takagi Worksite |
| 2022 |
Transitioned to the Tokyo Stock Exchange Standard Market |
| 2025 |
Implemented MBO (public offer for our shares by YAHO Inc.) |
| 2026 |
Delisting of shares |
