The O.S. company of Osaka, Japan is now the world's longest-surviving model engine manufacturer, having been established way back in 1936. Their record of 87 years in the business (and counting) seems highly unlikely to ever be challenged.

On its company website, the O.S. company still maintains a very informative pictorial record of the entire history of O.S. model engine production from the beginning way back in 1936. This feature has been widely used by collectors interested in Japanese engines to identify O.S. models in their possession.

This invaluable reference had its beginnings in 1976, when the company celebrated its 40^th year in business by publishing a printed "wall chart" rendition of their historical timeline as it then stood. Although this document only took the story up to 1976, it was still a most useful reference.

The on-line document has now been updated to bring the story up to 2020.  It may be found through this link. Owners of O.S. engines will find this to be an indespensable source.