There are three characters decipherable at the bottom of the picture, but they’re Japanese, not Chinese. Together, reading from right to left, they’re the characters for “Dai Nippon” or “Great Japan” in English:
本 日 大
The date will be given above that to the right and left, expressed as the year of the reign era, but the characters are too worn/corroded for me to read. It’s too late at night fpr me to go catalogue searching, but I think it will be late 1880s to early 1900s. It has a dragon obverse.
At 1.125 inches it’s too big to be a 5 yen, but I think it will be the right size for a 50 yen coin.