10 Ngultrum

The Royal Monetary Authority introduced hybrid substrate — a polymer-cotton composite — for this series at a time when most small Himalayan economies were still printing on conventional cotton-fibre paper. The choice was partly pragmatic: Bhutan's high-humidity monsoon seasons and the rough handling conditions in rural trade made standard paper notes unusually short-lived in circulation.

Pick 29 spans a remarkably long print run, with the 2006 through 2019 date range suggesting multiple print orders rather than a single issue, though distinguishing print years from face dates on this series requires attention to signature combinations.