I am having trouble identifying this coin. It is about 18-19 millimetres in size on the obverse (2nd image). I believe the three lower ideograms read “Yuan Tong Bao,” but I can not make out the top one. The reverse (1st image) I think has Mongolian script on it, but it's faded making it illegible. Any help would be greatly appreciated, although I understand this coin is very worn and how chinese cash coins can often look similar if not identical.
