You need to get that to a specialist in Chinese money. I know the round kind, but would not give an estimation of the knife money. I do know there are repros, but there are also ones that are authentic. And, if authentic, then some of them worth quite a bit of money. (I just recently went to a coin auction in Seoul, S. Korea, and they have had some knife money in previous auctions. It goes high, and there are definitely foreign coin collectors that are interested. BTW, did you dig this coin somewhere? Interesting piece. You should be able to see some kind of Chinese characters, if it is authentic. But, again, because you can see the characters doesn't necessarily mean it is ok. Hope you find out in your favor.