Li Chunfeng
Encyclopedia
Li Chunfeng (602–670) was a Chinese mathematician, astronomer
, and historian
who was born in today's Baoji, Shaanxi
during the Sui
and Tang
dynasties. He was first appointed to the Imperial Astronomy Bureau to help institute a calendar reform. He eventually ascended to deputy of the Imperial Astronomy Bureau and designed the Linde calendar. His father was an educated state official and also a Taoist. Li died in Chang'an
in 670.
of the era, despite that it had only been used for several years, was already having accuracy problems in predicting eclipses. In fact, Li was appointed partially because of his critique of the Wuyin calendar. Wang Xiaotong had been chosen to study the problem earlier. This was a very important job because of the Chinese belief in the Mandate of Heaven
. So if one altered the calendar, that person would have some control over the connection between the heavens and the emperor.
. It was called the Linde calendar. It improved the prediction of planets' positions and included an “intercalary month.” That is similar to the idea of a leap day. It would catch up a lunar year to a solar year because twelve lunar months are 1.3906 days short of one solar year. It was added every three years. The Linde calendar is the most prominent accomplishment of Li.
Li wrote a document complaining about the use of outdated equipment in the Imperial Astronomy Bureau, so he was commanded to construct a new armillary sphere. He completed it in 633. His construction had an additional third ring as opposed to the more common design of only two rings.
. He demonstrated that the least common multiple of the numbers two, three, four, five, six, seven, eight, nine, ten, eleven, and twelve was 27720, the answer was flawed in the original text. Yet another instance of this was in Zu Geng's work about the area of a sphere
. Li gave 22/7 (3.1428571428571428571428571428571) instead of three as a better approximation of what we know now as pi
. He began each annotation with the words “Your servant, Chunfeng, and his collaborators comment respectfully on…” Li did write some mathematical works of his own, little is known about them. They are usually dismissed as unimportant in comparison to his other accomplishments. With Liang Shu and Wang Zhenru, he wrote Shibu Suanjing (十部算经) in 656. These were ten mathematical manuals submitted to the emperor.
and Book of Jin
, which cover the history of the Sui and Jin dynasties. He wrote about the discoveries in astrology
, metrology
, and music
. These are the official histories
of the periods. The book Massage-Chart Prophecies is generally credited to Li. The book is a collaboration of attempts to predict the future using numerology. Therefore, Li is often thought of as being a prophet. The book gets it title from a poem near the end, discussing how much time it would take to tell the story of thousands of years, it would be better to take a break and enjoy a massage. Li wrote a book discussing the importance of astrology in Chinese culture called Yisizhan in 645. This is around when he would have been working on the Linde calendar. Yet another of is works is Commentary on and Introduction to the Gold Lock and the Flowing Pearls. In this book he describes Taoist customs that was probably part of influence from his father.
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
, and historian
Historian
A historian is a person who studies and writes about the past and is regarded as an authority on it. Historians are concerned with the continuous, methodical narrative and research of past events as relating to the human race; as well as the study of all history in time. If the individual is...
who was born in today's Baoji, Shaanxi
Baoji
Baoji is a prefecture-level city in Shaanxi province, China.-Geography:The prefecture-level city of Baoji has a population of 3,716,731 according to the 2010 Chinese census, inhabiting an area of . The city itself has a population of approximately 800,000. Surrounded on three sides by hills,...
during the Sui
Sui Dynasty
The Sui Dynasty was a powerful, but short-lived Imperial Chinese dynasty. Preceded by the Southern and Northern Dynasties, it ended nearly four centuries of division between rival regimes. It was followed by the Tang Dynasty....
and Tang
Tang Dynasty
The Tang Dynasty was an imperial dynasty of China preceded by the Sui Dynasty and followed by the Five Dynasties and Ten Kingdoms Period. It was founded by the Li family, who seized power during the decline and collapse of the Sui Empire...
dynasties. He was first appointed to the Imperial Astronomy Bureau to help institute a calendar reform. He eventually ascended to deputy of the Imperial Astronomy Bureau and designed the Linde calendar. His father was an educated state official and also a Taoist. Li died in Chang'an
Chang'an
Chang'an is an ancient capital of more than ten dynasties in Chinese history, today known as Xi'an. Chang'an literally means "Perpetual Peace" in Classical Chinese. During the short-lived Xin Dynasty, the city was renamed "Constant Peace" ; yet after its fall in AD 23, the old name was restored...
in 670.
Background and career
The Sui Dynasty was integral for uniting China, so it was a good time for learning. But when Li was sixteen the Sui fell, and the Tang rose. Nevertheless, the Tang did not harm the conditions for education. Indeed, it rather strengthened it. The Imperial Academy's math teaching was formalized. He was appointed into the Imperial Astronomy Bureau as an advanced court astronomer and historian, in 627. Once several years had passed, he then was promoted to deputy director of the Imperial Astronomy Bureau in 641, and even director in 648. He was given these titles because the Chinese calendarChinese calendar
The Chinese calendar is a lunisolar calendar, incorporating elements of a lunar calendar with those of a solar calendar. It is not exclusive to China, but followed by many other Asian cultures as well...
of the era, despite that it had only been used for several years, was already having accuracy problems in predicting eclipses. In fact, Li was appointed partially because of his critique of the Wuyin calendar. Wang Xiaotong had been chosen to study the problem earlier. This was a very important job because of the Chinese belief in the Mandate of Heaven
Mandate of Heaven
The Mandate of Heaven is a traditional Chinese philosophical concept concerning the legitimacy of rulers. It is similar to the European concept of the divine right of kings, in that both sought to legitimaze rule from divine approval; however, unlike the divine right of kings, the Mandate of...
. So if one altered the calendar, that person would have some control over the connection between the heavens and the emperor.
Astronomy and calendar
In 665, Li introduced a reform calendarCalendar
A calendar is a system of organizing days for social, religious, commercial, or administrative purposes. This is done by giving names to periods of time, typically days, weeks, months, and years. The name given to each day is known as a date. Periods in a calendar are usually, though not...
. It was called the Linde calendar. It improved the prediction of planets' positions and included an “intercalary month.” That is similar to the idea of a leap day. It would catch up a lunar year to a solar year because twelve lunar months are 1.3906 days short of one solar year. It was added every three years. The Linde calendar is the most prominent accomplishment of Li.
Li wrote a document complaining about the use of outdated equipment in the Imperial Astronomy Bureau, so he was commanded to construct a new armillary sphere. He completed it in 633. His construction had an additional third ring as opposed to the more common design of only two rings.
Mathematics
Li added corrections to certain mathematical works. Examples of this are in Nine Chapters on the Mathematical Art by Liu HuiLiu Hui
Liu Hui was a mathematician of the state of Cao Wei during the Three Kingdoms period of Chinese history. In 263, he edited and published a book with solutions to mathematical problems presented in the famous Chinese book of mathematic known as The Nine Chapters on the Mathematical Art .He was a...
. He demonstrated that the least common multiple of the numbers two, three, four, five, six, seven, eight, nine, ten, eleven, and twelve was 27720, the answer was flawed in the original text. Yet another instance of this was in Zu Geng's work about the area of a sphere
Sphere
A sphere is a perfectly round geometrical object in three-dimensional space, such as the shape of a round ball. Like a circle in two dimensions, a perfect sphere is completely symmetrical around its center, with all points on the surface lying the same distance r from the center point...
. Li gave 22/7 (3.1428571428571428571428571428571) instead of three as a better approximation of what we know now as pi
Pi
' is a mathematical constant that is the ratio of any circle's circumference to its diameter. is approximately equal to 3.14. Many formulae in mathematics, science, and engineering involve , which makes it one of the most important mathematical constants...
. He began each annotation with the words “Your servant, Chunfeng, and his collaborators comment respectfully on…” Li did write some mathematical works of his own, little is known about them. They are usually dismissed as unimportant in comparison to his other accomplishments. With Liang Shu and Wang Zhenru, he wrote Shibu Suanjing (十部算经) in 656. These were ten mathematical manuals submitted to the emperor.
Literary works
Li contributed to the Book of SuiBook of Sui
The Book of Sui was the official history of the Chinese dynasty Sui Dynasty, and it ranks among the official Twenty-Four Histories of imperial China. It was compiled by a team of historians led by the Tang Dynasty official Wei Zheng and was completed in 636.-External links:* of the Book of Sui,...
and Book of Jin
Book of Jin
The Book of Jin is one of the official Chinese historical works. It covers the history of Jin Dynasty from 265 to 420, which written by a number of officials commissioned by the court of Tang Dynasty, with the lead editor being the Prime Minister Fang Xuanling, drawing mostly from the official...
, which cover the history of the Sui and Jin dynasties. He wrote about the discoveries in astrology
Astrology
Astrology consists of a number of belief systems which hold that there is a relationship between astronomical phenomena and events in the human world...
, metrology
Metrology
Metrology is the science of measurement. Metrology includes all theoretical and practical aspects of measurement. The word comes from Greek μέτρον , "measure" + "λόγος" , amongst others meaning "speech, oration, discourse, quote, study, calculation, reason"...
, and music
Music
Music is an art form whose medium is sound and silence. Its common elements are pitch , rhythm , dynamics, and the sonic qualities of timbre and texture...
. These are the official histories
Twenty-Four Histories
The Twenty-Four Histories is a collection of Chinese historical books covering a period from 3000 BC to the Ming Dynasty in the 17th century. The whole set contains 3213 volumes and about 40 million words...
of the periods. The book Massage-Chart Prophecies is generally credited to Li. The book is a collaboration of attempts to predict the future using numerology. Therefore, Li is often thought of as being a prophet. The book gets it title from a poem near the end, discussing how much time it would take to tell the story of thousands of years, it would be better to take a break and enjoy a massage. Li wrote a book discussing the importance of astrology in Chinese culture called Yisizhan in 645. This is around when he would have been working on the Linde calendar. Yet another of is works is Commentary on and Introduction to the Gold Lock and the Flowing Pearls. In this book he describes Taoist customs that was probably part of influence from his father.
External links
- Li Chunfeng biography — The MacTutor History of Mathematics archive
- Liu Hui and Zu Gengzhi on the volume of a sphere