I was thinking about this the other day. They always confiscate prisoners’ cigarettes because they’re used as money. This actually makes the cigarettes more valuable if a prisoner can hold on to them. Imagine the look on the prisoners’ faces if the prison issued free and unlimited cigarettes to everyone. The entire economy would implode.
This seems to be a ledger, except that it's not written down! Oral history as money. (Is a community's collective memory transportable?)
> The ownership of a large stone, which would be too difficult to move, was established by its history as recorded in oral tradition rather than by its location. Appending a transfer to the oral history of the stone thus effected a change of ownership
And to show that memory and consensus are what's important, it doesn't even matter if you lose the stone:
> In one instance, a large rai being transported by canoe and outrigger was accidentally dropped and sank to the sea floor. Although it was never seen again, everyone agreed that the rai must still be there, so it continued to be transacted as any other stone.
It needs to be durable, transportable, divisible and difficult to counterfeit.
Famous example - cigarettes in a POW camp:
https://courses.cit.cornell.edu/econ4260/out/radford_pow.pdf