This neat little unit was the very first model diesel engine to enter series production in Japan. It was manufactured in small numbers by the famous O.S. company of Osaka during the early 1950's. Unlike many designs from that iconic company, it made no claims to any design originality, being pretty much a copy of the E.D. Mk. I Series 1 Bee of mid 1948 with a few detail modifications and some metrication of the dimensions. It was produced in two distinct series, but didn't make much of a sales mark and was never exported. Indeed, it made so little impression upon the O.S. company's corporate consciousness that like their sand-cast 29 sparker it was omitted from their famous 40^th anniversary summary sheet which incorrectly claimed to show all of the models that they had ever produced as of 1976! It is a very rare engine today.

A full review and test of this interesting semi-replica appears elsewhere on this website.