**Li Chunfeng** was a Chinese mathematician who worked in astronomy and calendar reform.

- He was born during the short lived Sui dynasty which was important in unifying a country which had been divided for over 300 years.
- It is a positive religion, emphasising the joyful and carefree sides of the Chinese character.
- It is also characterized by a positive, active attitude toward the occult and, as we shall see below, Li Chunfeng became to be regarded as a great astrologer and prophet through using numerology.
- When Li Chunfeng was sixteen years old, the Sui dynasty was replaced by the T'ang dynasty.
- It continued the educational development which had already begun, and formalised the teaching of mathematics at the Imperial Academy.
- Li rose to become a high-ranking court astronomer and historian, being first appointed to the Imperial Astronomical Bureau in 627.
- In ancient China there was a belief that a ruler received his right to rule from heaven.
- Changing the calendar was seen as one of the duties of the office, establishing the emperor's heavenly link on earth.
- After a change of ruler, and even more significantly after a change of dynasty, the new Chinese emperor would seek a new official calendar thus establishing a new rule with new celestial influences.
- Although the Chinese calendar had only been in operation for a few years, already predictions of eclipses were getting out of step.
- Wang Xiaotong had been appointed to the Imperial Astronomical Bureau a few years earlier to make recommendations.
- Li was promoted to become the deputy director of the Imperial Astronomical Bureau in about 641.
- We shall describe below some of the contributions Li made to mathematics through his work in astronomy and calendar reform.
- He assisted in compiling the official histories of the Jin and Sui dynasties.
- In the Jinshu (History of the Jin Dynasty) and Suishu (History of the Sui Dynasty) Li wrote the chapters on the developments in Chinese astronomy, astrology, metrology, and the mathematics of music through the relevant periods.
- In 648 Li was appointed as director of the Imperial Astronomical Bureau.
- As a consequence Li Chunfeng together with Liang Shu, an expert in mathematics from the ministry of education, and Wang Zhenru, a teacher from the national university and others were ordered by imperial decree to annotate the ten mathematical texts such as the Wucao suanjing or the Sunzi suanjing.
- Later Li worked on the Linde calendar, which was introduced in 665 and used until 728.
- The quotation we gave above suggests that Li was given the task of correcting and annotating mathematical texts.
- To give an example, he corrected a mistake in Liu Hui's comment on the least common multiple of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 in Problem 11 of Chapter 4 of the Nine Chapters on the Mathematical Art, giving the correct answer 27720.
- Li's comments in these texts are all clearly indicated (which is certainly not true for many other commentators).
- Li did make some original contributions to mathematics although he is not particularly famous in this respect.
- He developed a method of finite differences in his computations which he used in his work on the Linde calendar.
- We mentioned near the beginning of this article the influence of Taoist beliefs on Li. He wrote Commentary on and Introduction to the Gold Lock and Flowing Pearls, which was a book about Taoist practices.
- It is generally accepted, but not absolutely certain, that Li also wrote the Massage-Chart Prophecies.
- thousands of years need endless telling, so we'd better stop and enjoy a conformable massage.

Born 602, Shaanxi province, China. Died 670, Chang'an, China.

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Ancient Chinese, Astronomy, Chinese, Origin China, Puzzles And Problems

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**Oâ€™Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive