For some reason, the Carolus coins were more often (and more heavily) chopped than the Ferdins. This 1801 is a Typically weak date example, which MAY account for the heavy chops. The Chinese merchants were notoriously suspicious, and put their personal chop on a coin as a way of guaranteeing the authenticity of the coin. NOT to be confused with a Counterstamp, which is something ALLtogether different. There is a specialized market JUST for Chopmarked coins.