Though I usually hang out in the Russian forum, I also own two digital watches, a G-2800 solar G-Shock and this Casio Batteryless of unknown vintage:
A shot of the back under yellowish light to highlight the module information.
This watch belonged to my father in law and it had been sitting in the bottom of a box forever only to be rediscovered recently by my wife and given to me. I thought it was broken, but a day in the sun has brought it back to life.
I'm interested in finding out when it was manufactured or anything else about it. I suppose it must be an early version solar watch because of the lack of any alarm or stop-watch type functions.