On this day, 33 years ago, on June 1, 1992 (May 1, 1992, the lunar calendar), my country issued three metallic RMB. The People's Bank of China announced that it will issue RMB of one yuan, fifty cents and one cents nationwide starting from June 1, 1992. The one-yuan coin is made of a steel core inlaid with nickel, nickel white, round, with no teeth on the sides, a diameter of 25.00 mm, a thickness of 1.85 mm, and a single piece weighs 6.05 grams. The front design takes the national emblem of the People's Republic of China as the main scene. The country name in Chinese Pinyin is printed above the national emblem, and the country name and the casting year number are printed below the national emblem; The pattern on the back has peony as the main scenery, and the face value of "1 yuan" and its Chinese pinyin are printed on the upper right of the peony pattern. The pentagonal coin is made of brass alloy, golden yellow, round, with intermittent teeth on the sides, a diameter of 20.50 mm, a thickness of 1.65 mm, and a single piece weighs 3.80 grams. The front pattern takes the national emblem of the People's Republic of China as the main scene, with the name of the Chinese Pinyin printed on the top of the national emblem, and the country name and the casting year number printed on the bottom of the national emblem; the back pattern takes plum blossoms as the main scene, and the "5th Corner" and its Chinese Pinyin characters are printed on the upper right of the plum blossom pattern. The dime is made of aluminum alloy, silver-white, round, with a nine-sided shape on the inner periphery of the front and back, no teeth on the sides, a diameter of 22.50 mm, and a thickness of 2? 0 mm, and the mass of a single piece is 2.20 grams. The front pattern takes the national emblem of the People's Republic of China as the main scene, with the name of the Chinese Pinyin printed on the top of the national emblem, and the country name and the casting year number printed on the bottom of the national emblem; the back pattern takes the chrysanthemum as the main scene, and the face value of "1 jiao" and its Chinese Pinyin characters are printed on the upper right of the chrysanthemum pattern. A spokesperson for the People's Bank of China said that the new metal RMB has three characteristics: First, it is different from the current circulation metal coins in terms of pattern design style and literary expression, and it has strong national characteristics. On the basis of retaining the national emblem, Chinese characters, country names, and casting year numbers, the front pattern of the newly issued three types of metal RMB has added Chinese Pinyin country names; on the back pattern adopts asymmetric artistic techniques, respectively reproducing the three flowers of peony, plum blossom and chrysanthemum., and at the same time, it further highlights the currency denomination text. The pattern design is novel in composition, solemn and generous, and has a strong sense of the times and national style. Second, different denominations and different materials are used in the selection of coins, which is easy to distinguish. The newly issued three metal coins, one yuan, five jiao, and one jiao, respectively use three different materials: nickel plating on steel core, copper alloy, and aluminum alloy. This material has different colors and specific weights, making it easy to distinguish. Among them, the one-yuan coin is made of a new international material, which has the characteristics of beautiful appearance, wear resistance, corrosion resistance, etc., and has low casting costs; the pentagon coin is made of a technologically improved copper alloy, with golden color and high anti-discoloration properties; The dime is made of the aluminum alloy material of the current currency coins, which is light and low cost. The third is to break through the traditional practice of larger denomination and larger size in terms of size specifications, making it more reasonable. The diameters of the three newly issued metal coins, one yuan, five jiao, and one jiao, are 25.0 mm and 22.5 mm respectively; the side thicknesses are 1.85 mm, 1.65 mm, and 2.4 mm respectively. In addition to the obvious increase in thickness, the aluminum alloy coin adopts the design scheme of nine-sided outer circle inner periphery and no thread teeth at the edge, which can be obviously distinguished from the current aluminum coin by vision and hand feeling.