20 000 Rupiah with security thread

Bank Indonesia introduced the security thread to this denomination during the early 1990s as part of a broader anti-counterfeiting upgrade across the rupiah series — the move came during a period of rapid economic expansion in Indonesia when banknote volumes were climbing steeply and counterfeiting pressure on higher denominations was a documented concern for the central bank.

Perum Peruri, the state-owned security printer established in 1971 and based at Karawang in West Java, has handled rupiah production domestically since its founding — unusual for a developing economy of that period, which more commonly contracted European or American security printers.