2c Papua & New Guinea postage stamp of 1971 with bogus surcharge "Rp. 20,- PAPUA MERDEKA" in black, supposedly produced by the Organisasi Papua Merdeka (OPM, Free Papua Movement)
The overprint was allegedly produced for use on local courier mail in OPM-controlled areas around the Indonesia-Papua New Guinea border, but there is no evidence that such a courier service ever existed. In 1979, the Papua New Guinea Postal Administration declared these overprints to be illegal and invalid for postage.
