AU followed by a number typically indicates the thickness of the gold plating. If it has a stainless back it is usually gold plated. Typically it would say 583 if it is solid gold.
However if there is any doubt whatsoever have it tested because sometimes the common knowledge doesn't apply. Chaika did some interesting alloys and platings.
I have a ladies one but is closer to 16k and has an unusual symbol next to the AU, but not the typical 583 hallmark.
Re: Russian Medical Watch
Yanka is Chaika which translates to Seagull.
They typically made ladies watches.
AU followed by a number typically indicates the thickness of the gold plating. If it has a stainless back it is usually gold plated. Typically it would say 583 if it is solid gold.
However if there is any doubt whatsoever have it tested because sometimes the common knowledge doesn't apply. Chaika did some interesting alloys and platings.
I have a ladies one but is closer to 16k and has an unusual symbol next to the AU, but not the typical 583 hallmark.
Re: Russian Medical Watch
RARE Vintage Soviet Ussr Russian QUARTZ Watch CHAIKA Medical Pulsemeter
Value: 93$-110$