If it looks anything like this coin, then it is a bronze coin of Emperor Hui Tsung who ruled from 1102-1107 AD. The symbols do not look similar, but hopefully so me of this information may help. Greg
Since there are literally thousands of Chinese/Japanese/Korean/Annamese cash coins, produced over more than a millenium, nearly all of them having four characters on the obverse, that statement is simply wrong. A quick scan through Fisher's Ding doesn't turn up a reverse design remotely similar to the posted item, and there is a high probability that it is a temple charm rather than a coin. We'll know more in a couple of hours when my source for reading Chinese calligraphy is available to look at it. BTW the character on the right side of the obverse belongs at the top. It's unclear whether the reverse design should be rotated to the right or the left as I can't discern any writing in the design.