Unknown Ref. Number

I have found an (to me) unusual Automatic from the 70ies or 80ies. Does anybody have an idea what reference this could be? It looks like it has a "closed" caseback. There is absolutely no gap visible, where it could be opened. 

Any help is appreciated.

Best, Peter

Hi YC1811,

this is a special case indeed. Most probably a monocoque design, where the movement is only acessible from the front.

Nice Watch.

I checked the Dealers Handbook for 1980. No such case is depicted there.

br Cromagnonman

Hi YC1811,

the Ref. Nr is most probably 1914.

br Cromagnonman

Hello, YC1811 

Indeed, this is a unique situation. The design is most likely monocoque, with the movement only accessible from the front. 
Good watch. 
I looked at the 1980 Dealers Handbook. There, no such case is shown.