Yap Stone Money (Rai)
Rai stones (or Yap stone money) are large carved limestone discs used as currency on the Micronesian Island of Yap, possibly dating to 500 CE and still used today. Stones were mined on Palau, 400 km away, and transported by canoe.
Key characteristic: Value was not based on size but on oral provenance history — memorised by the village chief and tracked communally. A stone’s entire transaction history was publicly known, making theft pointless. No central bank or record-keeper was needed.
This “distributed public ledger” structure is now recognised as a conceptual precursor to bitcoin’s blockchain:
| Rai System | Bitcoin |
|---|---|
| Oral history | Blockchain ledger |
| Community verification | Distributed node consensus |
| No central authority | Decentralised network |
Only two Rai stones exist in Canada: one at the Bank of Canada Museum, one donated to the University of Calgary’s Nickle Galleries in 2019.