My gut reaction is Japanese, But could be Chinese, I can't find my glasses and its making this harder but that's the area as for age I am not so sure, Its a great find well done on that.
The mercury dime is there for size comparison. I spent a few hours last night on a Chinese cash coin site but couldn't find one that matched. All I learned for sure is that the some of the older ones lack any scripting on the obverse.
unclemac "Said try Korean" Thanks Think I have a pretty decent match here. Korean Coins And quoting this site "Koryo Period (Goryeo 高 麗) (936-1392 AD)" And they make it sound like this coin is rare perhaps, how rare remains to be seen Will keep looking for more information.Thanks for looking CARM