1919	Minoji Hashiguchi establishes Kameido rubber factory in Tokyo
1920	Heisen Yoko chemicals division established at Kameido rubber factory with the purpose of importing and selling rubber
1921	Contract signed to act as agent for Bayer of Germany
1924	Heisen Yoko chemical division established as a joint stock company Active in sales and publicity for Bayer's rubber additives as sole agent in Japan
1927	Approved as Asian agent for Bayer's rubber additives Kobe office opened
1928	Rubber laboratory opened, along with department for training rubber technicians
1933	Heisen Yoko Chemical Division becomes a limited company
1939	Rubber research laboratory moved to Tokyo, facilities opened to facilitate development of the domestic rubber trade
1943	Chemical imports halted as a result of World War Two: business suspended
1950	Imports of Bayer rubber additives resumed after ratification of trade treaty with West Germany Heisen Yoko Co Ltd established and Minoji Hashiguchi becomes managing director
1955	Agent for the introduction of Bayer's polyurethane technology, raw material sales begin
1956	Kansai sales office opened
1961	Minoji Hashiguchi passes away
1966	Fully owned subsidiary Koyo Sangyo Co Ltd established
1973	Joint venture with Impatex AG of Switzerland, H&K Ltd established, to manufacture polyurethane resin
1983	Nagoya sales office established
1995	Headquarters moved to Taito Ward in Tokyo
1998	Kansai sales office moved from Kobe to Osaka
2000	Kyushu branch established in Kita Kyushu City
2003	Environmental management system ISO14001 certification obtained
2011	Shanghai Rep.Office Opened
2012	Shanghai Rep.Office Closed
	Heisen Trading(Shanghai)Co., Ltd. established