Coins of the Indian rupee (INR) were first minted in 1950. New coins have been produced annually since then and they make up a valuable aspect of the Indian currency system. Today, circulating coins exist in denominations of One Rupee, Two Rupees, Five Rupees, Ten Rupees and Twenty Rupees. All of these are produced by four mints located across India, in Kolkata, Mumbai, Hyderabad, Noida. History After Indian independence in 1947, British Indian coins were in use as a frozen currency until the dominion of India became a republic in 1950. The first rupee coins of the Republic of India were minted in 1950. These included 1/2 rupee, 1/4 rupee, 2 anna, 1 anna, 1/2 anna & 1 pice coins, and are referred to as the anna series or pre-decimal coinage. Under the anna series, one rupee was divided into 16 annas or 64 pice, with each anna equal to 4 pice. In 1957, India shifted to the decimal system, though for a short period of time, both decimal and non-decimal coins were in circulation. To distinguish between the two pice coins in circulation, the coins minted between 1957 and 1964 were printed with the legend “Naya Paisa” (“New Paisa”). The denominations in circulation were 1, 2, 3, 5, 10, 20, 25, 50 (naya) paisa and one rupee. Since rupees retained their pre-decimal value, pre-decimal coins of one, half and quarter rupees remained in circulation after decimalisation. The word "naya" was dropped in 1964 and a new denomination, the 3 paisa, was introduced into circulation. A 20 paisa coin was minted in 1968. Neither of these coins gained much popularity. The 1, 2 and 3 paisa coins were phased out gradually in the 1970s. In 1982, a new 2 rupee coin was introduced experimentally to replace 2 rupee notes. The 2 rupee coin was not minted again till 1990, after which it was minted every following year. Stainless steel coinage of 10, 25 and 50 paisa was introduced in 1988. In 1992, a new stainless steel rupee coin, smaller and lighter than the older rupee, was minted, alongside a 5 rupee Cupronickel coin. In 2005, the 10 rupee coin was minted for the first time. Higher denomination coins were introduced due to an increasing demand for change and the increasing cost of printing 2, 5 and 10 rupee banknotes. On 30 June 2011, all coins in denominations of 25 paisa