20 000 Riels

The 20,000 Riel denomination was introduced in 1995 as Cambodia's highest-value note at the time, a necessity driven by persistent inflation that had eroded the purchasing power of lower denominations since the riel's reintroduction in 1980 — the Khmer Rouge had abolished currency entirely during their 1975–1979 rule, physically destroying the National Bank and burning its reserves.

Oberthur's production for the National Bank of Cambodia through the 1990s was routine work, and the security specification here is minimal — watermark only, no security thread, no foil. That thinness made the series a known target for counterfeiting in the late 1990s.