| 1951 | Kotobuki Sangyo Co., Ltd. established Acknowledged as a regular trader with Fuji Iron & Steel Co., Ltd. Muroran Works |
|---|---|
| 1962 | Tokyo Branch (currently Tokyo Sales Office) established |
| 1963 | Mill roller guide developed and registered as a new practical proposal |
| 1967 | Hassamu factory constructed within Sapporo steel industry estate |
| 1971 | Sendai Sales Office established |
| 1977 | Osaka Sales Office established |
| 1982 | Okayama Sales Office established |
| 1983 | Nagoya Satellite Office (currently Nagoya Sales Office) established New factories added to the Hassamu factory complex Kisarazu Satellite Office established |
| 1988 | Kyushu Satellite Office (currently Kyushu Sales Office) established |
| 1990 | Rifu factory and new company premises established in the town of Rifu, Miyagi prefecture |
| 1991 | Kotobuki Sangyo Kikai (currently Kotobuki Machinery Co., Ltd.) established |
| 2000 | ISO9001 certification received (Hassamu factory) Private placement bonds issued |
| 2005 | Zenibako factory established in Zenibako, Otaru |
| 2006 | Hassamu factory renovated |
| 2019 | Headquarters renovated |
| 2021 | Osaka sales office moved to Shinei Daiichi Bld.2F, 3-34-15, Tarumi-cho, Suita-shi, Osaka |