Indonesian rupiah coinage was first issued in 1951 and 1952, a year or so later than the first Indonesian rupiah banknotes printed following the peace treaty with The Netherlands, agreed in November 1949. Although revolutionary currency had been issued in by the provisional Republic of Indonesia between the declaration of independent on 17 August 1945 and 1949, it had all been formed of paper, metal being far too scarce for the internationally isolated government to use as currency.
Due to high inflation in the late 1950s and early 1960s, no coins were minted after 1961, and that which remained in circulation was effectively worthless.
A devalued 'new rupiah' was issued in an attempt to tame inflation in 1965, with banknotes in denominations all the way from 1 sen (1 cent) up to 100 rupiah - no coins were struck at this time. By 1971, however, the economy, and inflation, under Suharto's New Order was stable, and coinage was once again issued, in denominations of 1, 5, 10, 25 and 50 rupiah, with 100 rupiah added two years later. Due to inflation, the current coinage now consists of 25, 50, 100, 200, 500 and 1000 rupiah, although older 1 rupiah coins remain officially legal tender for completeness.
Unlike coinage of the Netherlands Indian gulden (which in higher denominations were made of silver or gold), circulating rupiah coinage has always been formed of base metal.
For the first couple of years until sufficient coins had been issued, government sen notes were circulated, of 10, 25 and 50 sen denominations. No lower denominations were printed, but the old bronze Netherlands Indies gulden coins of 1/2, 1 and 2½ sen remained as legal tender (higher denominations, starting from 1/20 gulden (5 sen) had been silver, with greater intrinsic metal value).
Coinage, issued in 1951 and 1952 and from then until 1961, replaced the notes as sufficient coinage entered circulation. Under Indonesian law originally enacted by the Dutch, issue of money below 5 rupiah (in Dutch times gulden), was the responsibility of the government, and hence all coins bore the name of Indonesia, rather than the central bank.
The denominations were 1, 5, 10, 25 and 50 sen. The 1 and 5 sen coins had centre holes, similar to the old copper coins of the Dutch, while the other coins were solid. All were aluminium except the 50 sen, which was copper-nickel. 1 sen coins were effectively worthless, and only a token number of 100,000 were minted, all dated 1952. 5 sen coins were more useful and were also minted dated 1954, as was the 10 sen.
From 1954, Indonesia began to eliminate use of Malay Arabic script (Jawi), which had been a feature of the coins of the Netherlands Indies as well as of past Islamic sultanates in the archipelago. The 50 sen coin was the first to be changed, with the Arabic text simply removed from the coin for its 1954-dated minting.