5 Kina Bougainville

The Bank of Bougainville is not a central bank in the conventional sense — it was established as part of Bougainville's incremental push toward full independence from Papua New Guinea, issuing notes that function more as assertion of sovereign intent than practical currency. The Autonomous Region of Bougainville had no independent monetary system at the time of issue; PNG Kina remained the operative tender, which means these notes circulated, if at all, in an entirely unofficial capacity.

A watermark as the sole security feature is notably sparse for a 2015–2016 issue, suggesting a short production run with limited investment — consistent with what were likely commemorative or promotional printings rather than banknotes intended for sustained daily use.