China. People’s Republic
Founders of Chinese Culture Series
1989 Silver Proof 5 Yuan 36mm (22.22 grams) 0.900 Silver (0.643 oz. ASW)
Reference: KM# 250, Y# 215
Certification: NGC  PF 68 ULTRA CAMEO 2839329-022
中华人民共和国 1989, The emblem of the People’s Republic of China.
郭守敬 1231-1316年 5元, Guo Shoujing, Scientist, right.

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Guo Shoujing (Chinese: 郭守敬, 1231-1316), courtesy name Ruosi (若思), was a Chinese astronomer,hydraulic engineer, mathematician, and politician who lived during the Yuan Dynasty (1271-1368). The later Johann Adam Schall von Bell (1591-1666) was so impressed with the preserved astronomical instruments of Guo that he called him “the Tycho Brahe of China.”Jamal ad-Din cooperated with him.

Guo Shoujing was a major influence in the development of science in China. The tools he invented for astronomy allowed him to calculate an accurate length for the year, which allowed Chinese culture to set up a whole new system of exact dates and times, allowing for increasingly accurate recording of history and a sense of continuity throughout the country. The calendar stabilized the Chinese culture allowing subsequent dynasties to rule more effectively. Through his work in astronomy, he was also able to more accurately establish the location of celestial bodies and the angles of the Sun relative to Earth. He invented a tool which could be used as an astrological compass, helping people find north using the stars instead of magnets.

Within the field of hydraulics, even at a young age, Guo was revolutionizing old inventions. His work on clocks, irrigation, reservoirs, and equilibrium stations within other machines allowed for a more effective or accurate result. The watches he perfected through his work in hydraulics allowed for an extremely accurate reading of the time. For irrigation, he provided hydraulics systems which distributed water equally and swiftly, which allowed communities to trade more effectively, and therefore prosper. His most memorable engineering feat is the man-made Kunming Lake in Beijing, which provided water for all of the surrounding area of Beijing and allowed for the best grain transport system in the country. His work with other such reservoirs allowed people in inner China access to water for planting, drinking, and trading. Guo’s work in mathematics was regarded as the most highly knowledgeable in China for 400 years. Guo worked on spherical trigonometry, using a system of approximation to find arc lengths and angles. He stated that pi was equal to 3, leading to a complex sequence of equations which came up with an answer more accurate than the answer that would have resulted if he did the same sequence of equations, but instead having pi equal to 3.1415.

As people began to add onto his work, the authenticity of his work was questioned. Some believe that he took Middle Eastern mathematical and theoretical ideas and used them as his own, taking all the credit.However, he never left China which would have made it more difficult for him to access others’ ideas. Otherwise, Guo was highly regarded throughout history, by many cultures, as a precursor of the Gregorian calendar as well as the man who perfected irrigation techniques in the new millennium. Many historians regard him as the most prominent Chinese astronomer, engineer, and mathematician of all time.

His calendar would be used for the next 363 years, the longest period during which a calendar would be used in Chinese history.He also used mathematical functions in his work relating to spherical trigonometry, building upon the knowledge of Shen Kuo’s (1031-1095) earlier work in trigonometry. It is debated amongst scholars whether or not his work in trigonometry was based entirely on the work of Shen, or whether it was partially influenced by Islamic mathematics which was largely accepted at Kublai’s court. Sal Restivo asserts that Guo Shoujing’s work in trigonometry was directly influenced by Shen’s work. An important work in trigonometry in China would not be printed again until the collaborative efforts of Xu Guangqi and his Italian Jesuit associate Matteo Ricci in 1607, during the late Ming Dynasty.

China, officially the People’s Republic of China (PRC) since 1949, is a country in East Asia and the world’s most populous country, with a population of around 1.404 billion. Covering approximately 9,600,000 square kilometers (3,700,000 sq mi), it is the third- or fourth-largest country by total area, depending on the source consulted. Governed by the Communist Party of China, the state exercises jurisdiction over 22 provinces, five autonomous regions, four direct-controlled municipalities (Beijing, Tianjin, Shanghai, and Chongqing), and the special administrative regions of Hong Kong and Macau.

China emerged as one of the world’s earliest civilizations, in the fertile basin of the Yellow River in the North China Plain. For millennia, China’s political system was based on hereditary monarchies, or dynasties, beginning with the semi-legendary Xia dynasty in 21st century BCE. Since then, China has expanded, fractured, and re-unified numerous times. In the 3rd century BCE, the Qin unified core China and established the first Chinese empire. The succeeding Han dynasty, which ruled from 206 BC until 220 AD, saw some of the most advanced technology at that time, including papermaking and the compass, along with agricultural and medical improvements. The invention of gunpowder and movable type in the Tang dynasty (618-907) and Northern Song (960-1127) completed the Four Great Inventions. Tang culture spread widely in Asia, as the new maritime Silk Route brought traders to as far as Mesopotamia and Horn of Africa. Dynastic rule ended in 1912 with the Xinhai Revolution, when a republic replaced the Qing dynasty. The Chinese Civil War resulted in a division of territory in 1949, when the Communist Party of China established the People’s Republic of China, a unitary one-party sovereign state on Mainland China, while the Kuomintang-led government retreated to the island of Taiwan. The political status of Taiwan remains disputed.

Since the introduction of economic reforms in 1978, China’s economy has been one of the world’s fastest-growing with annual growth rates consistently above 6 percent. As of 2016, it is the world’s second-largest economy by nominal GDP and largest by purchasing power parity (PPP). China is also the world’s largest exporter and second-largest importer of goods. China is a recognized nuclear weapons state and has the world’s largest standing army and second-largest defense budget. The PRC is a permanent member of the United Nations Security Council as it replaced the ROC in 1971, as well as an active global partner of ASEAN Plus mechanism. China is also a leading member of numerous formal and informal multilateral organizations, including the Shanghai Cooperation Organization (SCO), WTO, APEC, BRICS, the BCIM, and the G20. China is a great power and a major regional power within Asia, and has been characterized as a potential superpower.