| March 1991 | Established KOHKEN Denka Co., Ltd. in Saiwai-ku, Kawasaki City |
| June 1994 | Head office moved to Midori Ward, Yokohama |
| May 2010 | Company organization is "Product Sales Division" "Original Parts Product Division" "Surface Treatment Division ”and“ OEM Division ” |
| May 2010 | Product Sales Division becomes an authorized dealer of Brembo Japan Motorcycle Co., Ltd. |
| May 2010 | Opened sales headquarters in Midori Ward, Yokohama |
June 2010 |
Changed company name to Koken Co., Ltd. |
May 2014 |
Relocated all business units to Tsuzuki Ward, Yokohama |
