Irian Barat, also known as Irian Jaya and West Irian, is the western half of the island of New Guinea. It was formerly Netherlands New Guinea. Indonesia took control of the territory in 1963. The following year Indonesia issued special coins for exclusive use in the territory. The value of the coins was based on the Netherlands New Guinea Gulden which had been used in the territory, rather than the Indonesian Rupiah. Because of this they were worth substantially more than their Indonesian counterparts. The aluminum coins depicted Indonesian President Sukarno one side and had the denomination on the other. Though issued in 1964, the coins were dated 1962. The coins were withdrawn from circulation in 1971 and exchanged at the rate of 1 Irian Barat Rupiah for 18.9 Indonesian Rupiahs. This 4 coin set from Irian Barat includes the 5, 10, 25 and 50 Sen.