The second edition of the commemorative cover series "Important Scientific and Technological Inventions and Creations in Ancient China" premiered on the 17th. The second series released a total of 9 commemorative covers, including: Mawangdui Map, Grand Canal, Astronomical Records, Materia Medica, Rice Cultivation, Gougu Rongyuan, Movable Type Printing, Xinmang Copper Calipers, and Watertight Bulkheads, which belong to the categories of Optical Geology and Rhythm, Civil Engineering, Astronomy, Medicine, Agriculture and Textile, Mathematics, Materials and Systems, Machinery and Instruments, Vehicles and Ships, Gunpowder and Firearms. Among them, the movable type printing commemorative cover uses a special ironing process to display the vivid state of ink falling on the paper before it dries. The commemorative covers of Important Scientific and Technological Inventions in Ancient China were jointly launched by China Post, the Science Communication Bureau of the Chinese Academy of Sciences, and the Science and Technology Communication Center of the Chinese Association for Science and Technology. They are the sub series of the commemorative covers of China Post's science communication series. This series of commemorative covers is based on 88 designs of "Important Scientific and Technological Inventions in Ancient China", a phased research achievement of the Institute of the History of Natural Science of the Chinese Academy of Sciences, and is planned to be distributed in 10 series in three years. On May 31, 2023, the first edition has been officially released; The third episode will be released on December 22nd. (New News Agency)