Towards the end of the 3rd century BC the dukes of Yi started to issue round coins with a square hole. Their values were given in huo – the same currency thus as the knife coins. This specimen has a value of 6 huo, yet huo coins with lower values also existed. With those issues the county of Yi got small huo-denominations for the first time, as the knife coins were all of high values. This made trade a lot easier.