货币的出现是人类商业文明走向成熟的重要标志之一。而在春秋战国时期，出现了一种形似小刀的货币成为各诸侯国的重要货币，赵国都城邯郸就出土了很这样的青铜“刀币”，而上面的出现的“甘丹”二字，表明在当时，邯郸城也叫“甘丹”（读音同邯郸）。
Knife money is the physical object of monetary history， but also the witness of history. Therefore， it is necessary to know its place in history before collecting it. Following the collection principle of “rare things are valuable”， we should not only see whether the age is long， the length of circulation time， but also see how many knives and coins of Qi， Yan and Zhao and cloth coins of Han， Wei and Qin are old. They are rarer than round money， expensive and have high collection value and historical research value.
