Zhang Heng

Overview

Zhang Heng (78-139 CE), also known as Zhang Pingzi, was a polymath of the Eastern Han Dynasty in ancient China. Renowned across multiple fields including astronomy, mathematics, seismology, literature, and mechanical engineering, Zhang Heng made significant contributions to Chinese science and culture. His most famous inventions include the world's first seismoscope and an armillary sphere powered by water clock mechanisms. As a literary figure, he is regarded as one of the "Four Masters of Han Fu" alongside Sima Xiangru, Yang Xiong, and Ban Gu.

History

Early Education and Travel

Zhang Heng was born into a prominent family in Nanyang in 78 CE. His grandfather, Zhang Kan, had served as governor of Shu Commandery during the early Eastern Han Dynasty. From a young age, Zhang Heng demonstrated exceptional scholarly abilities, composing essays in his childhood. In 93 CE, he left his hometown to study in the Sanfu region (present-day Guanzhong area in Shaanxi), where the magnificent landscapes and ancient capitals provided rich material for his later work "Xijing Fu" (Rhapsody on the Western Capital).

In 95 CE, during his journey from Sanfu to the imperial capital Luoyang (also called Luo or Luoyi), Zhang Heng passed by Lishan Mountain and composed "Wenquan Fu" (Rhapsody on the Hot Springs). Upon reaching Luoyang, he entered the Imperial Academy (Taixue) to study Confucian classics, receiving guidance from renowned Confucian scholars. During this period, he became familiar with the customs and culture of the capital, conducting extensive research for his "Dongjing Fu" (Rhapsody on the Eastern Capital). He also befriended Cui Yuan, who would become his lifelong friend, and completed "Qi Bian" and "Ding Qing Fu" during this time.

Official Career in Nanyang

During the Yongyuan era (89-105 CE), Zhang Heng was recommended as Xiaolian (filial and incorruptible), but he declined the appointment. The government repeatedly summoned him to official positions, which he also refused. In 99 CE, Zhang Heng returned to Nanyang from the capital. The following year, at the invitation of Nanyang Prefect Bao De, he served as Zhubu (secretary), managing official documents. During this position, Zhang Heng was highly valued by Bao De and wrote several pieces on his behalf, including "Shousi Ming," "Situ Lü Gong Lei," and "Situ Chen Gong Lei."

To criticize the excessive luxury of nobles and officials during a long period of peace, Zhang Heng spent ten years painstakingly creating "Er Jing Fu" (The Two Capitals Rhapsody), modeled after Ban Gu's "Liang Du Fu" (Rhapsody on the Two Capitals). Zhang Heng's "Er Jing Fu" was monumental in scale and later acclaimed in literary history as "the pinnacle of long-form rhapsodies." His descriptions of Western Capital customs also serve as important historical materials for later research.

Scholarly Retirement

In 108 CE, Bao De was transferred to become Minister of Agriculture, and Zhang Heng resigned his secretary position to focus on scholarly pursuits. During this period, he achieved profound expertise in astronomy, yin-yang cosmology, and calendrical calculations, becoming particularly engrossed in studying the "Xuan Jing" (The Mysterious Classic). General Deng Zhi admired Zhang Heng's talents and repeatedly summoned him to official service, but Zhang Heng consistently declined. In 110 CE, he completed "Nan Du Fu" (Rhapsody on the Southern Capital).

Service in the Imperial Court

In 111 CE, the imperial court, now led by Empress Dowager Deng Sui, learned of Zhang Heng's expertise in "shuxue" (mathematical arts and numerology) and summoned him to the capital, appointing him as Lang (gentleman of the interior). In 112 CE, he participated with Liu Zhen in formulating the rituals of the Han Dynasty. During this period, he completed "Yu Cui Yuan Shu," "Tai Xuan Jing Zhu" (Commentary on the Mysterious Classic), "Xuan Tu," and "Da Sinong Bao De Lei."

In 114 CE, he was promoted to Shangshu Shilang (Gentleman of the Imperial Secretariat) and authored "Huangdi Feiniao Li" (Yellow Emperor's Flying Bird Calendar). During this time, Zhang Heng's friendship with Cui Yuan deepened. He once told Cui Yuan: "After studying the 'Tai Xuan,' I have come to understand that Ziyun (Yang Xiong's courtesy name) has profoundly grasped the principles of the Dao, comparable to the Five Classics. It is not merely a commentary, but enables one to discuss yin and yang matters. It is the most significant book of our Han Dynasty in two hundred years. In another two hundred years, will the 'Tai Xuan Jing' decline? Because the fate of its author must manifest in his generation, this is a natural verification. When the Han Dynasty reaches its four hundred years, the study of 'Xuan' will flourish again."

First Tenure as Grand Historian

In 115 CE, Zhang Heng was promoted to Taishiling (Grand Historian), responsible for astronomy, calendrical science, mathematical calculations, and imperial archives. This period marked his most fertile time for scientific innovation and achievement. In 117 CE, he invented the water-powered armillary sphere. During this time, he authored "Dixing Tu" (Map of Terrain), "Hunyi Zhu" (Commentary on the Armillary Sphere), "Lou Shui Zhuan Hun Tian Yi Zhu" (Commentary on the Water-Driven Armillary Sphere), "Ling Xian" (Spiritual Constitution), "Ling Xian Tu" (Illustrations of the Spiritual Constitution), and "Suan Wang Lun" (Discourse on the Net of Calculation), among which "Ling Xian" is considered China's first theoretical work on astronomy.

Service as Palace Gate Commandant

In 121 CE, Empress Dowager Deng Sui died, and Emperor An of Han took personal control of the government. Zhang Heng was transferred to serve as Gongche Sima Ling (Commandant of the Palace Gate), responsible for guarding the Simamen Gate of the palace and receiving official visitors. During this period, he wrote "Yu Tejin Shu," "Tong Zhou Xing Yi Li," "Dong Xun Gao," and "Ri Shang Biao."

Zhang Heng hoped to regain his position as Grand Historian to continue his academic research and composed "Yu Tejin Shu" to seek assistance from Deng Zhi, stating: "Penglai is the secret repository of the Grand Historian, valued by the Daoists. If I could serve in that position again, I would consider myself fortunate." However, Deng Zhi soon fell in political struggles and was forced to commit suicide. Due to his close association with Deng Zhi, Zhang Heng was unable to advance in his official career for many years.

Second Tenure as Grand Historian

In 126 CE, during the reign of Emperor Shun, Zhang Heng returned to his position as Grand Historian. Given that people mocked him for "not having the momentum for advancement" and "considered him disheartened," Zhang Heng composed "Ying Jian" (Response to Criticism) that same year, expressing his philosophy: "I do not worry about not having a high position, but worry about not having noble virtue; I am not ashamed of having meager salary, but ashamed of having limited knowledge."

In 132 CE, he created the world's first instrument for detecting the direction of earthquakes—the seismoscope (houfeng didongyi). He also invented a meteorological instrument called the houfengyi (anemometer), created a self-steering south-pointing chariot with three wheels, and a wooden automaton that could fly on its own. In response to the popular "chenwei studies" (apocryphal and prophetic texts) of his time, Zhang Heng submitted "Lun Gong Ju Shu" (Memorial on Recommending Officials) to expose the fallacies of chenwei. During this period, he also authored "Shun Di Feng Shi," "Hong Fu Bing Xu," "Wu Fu Bing Xu," "Yu Lie Fu," and "Chen Shu Shu."

Promotion to Palace Attendant

In 133 CE, Zhang Heng was promoted to Shizhong (Palace Attendant). Emperor Shun once asked Zhang Heng in the imperial court about the people hated by the realm. The eunuchs feared he might speak ill of them and stared at him threateningly. Zhang Heng could only answer vaguely and then left the court. Often contemplating how to preserve himself and his family, he believed that good and bad fortune, fortune and misfortune, were obscure and difficult to comprehend. Thus, he composed "Si Xuan Fu" (Rhapsody on Profound Thoughts) to express and convey his aspirations.

During the Yongchu era (107-113 CE), Ye Zhe She Liu Zhen and Xiaoshu Lang Liu Tuntu had been compiling the "Han Ji" (Book of Han) at the Dongguan Pavilion and had invited Zhang Heng to participate in discussions regarding Han Dynasty rituals, but both men died soon after. After becoming Palace Attendant, Zhang Heng collected scattered documents to supplement and correct the "Han Ji." He pointed out that more than ten matters recorded by Sima Qian and Ban Gu did not match other historical sources. Zhang Heng also believed that Wang Mang's biography should only record his usurpation of the Han throne, while his reign years and supernatural phenomena after usurpation could be included in the "Empress Yuan's Biography." He further argued that the Gengshi reign title should precede that of Guangwu, as people generally considered Gengshi Emperor as the legitimate ruler, and even Emperor Guangwu Liu Xiu had initially served as a general under Gengshi before ascending the throne. Zhang Heng repeatedly presented these proposals, but they were not adopted. Subsequently, many of his writings were not preserved in the imperial archives, which later generations greatly regretted.

Governor of Hejian

Zhang Heng often remained by Emperor Shun's side but did not align with the eunuch faction. The eunuchs consistently viewed him as a threat and constantly slandered him before the emperor. In 137 CE, Zhang Heng was pushed out of the capital and appointed as the Chancellor (Xiang) of Hejian. The Hejian Prince Liu Zheng was extravagant and dissolute, disregarding laws and regulations. Additionally, many powerful local gentry had formed groups to cause unrest. After taking office, Zhang Heng strictly enforced laws and regulations, cracked down on powerful families, and secretly identified the names of the treacherous faction. He arrested them all at once, bringing order to the region. His administration was known for its integrity. However, Zhang Heng already felt the court was corrupt and difficult to serve, so he wrote "Yuan Pian" (Lament) and "Si Chou Shi" (Four Sorrows Poem) to express his feelings. He also composed "Du Lou Fu" (Rhapsody on the Skull) and "Zhong Fu" (Rhapsody on the Tomb).

In 138 CE, Zhang Heng wrote "Gui Tian Fu" (Rhapsody on Returning to Fields) and requested to end his provincial service and return to the capital. Emperor Shun approved his request and appointed him as Shangshu (Secretary). The following year, Zhang Heng died in his position as Shangshu at the age of sixty-two, in a state of melancholy and desolation. He was buried in his hometown of Xie, Nanyang, and was posthumously honored as "Bo of Xie" during the Northern Song Dynasty.

Key Information

Cultural Significance

Zhang Heng's contributions span multiple fields of knowledge, making him one of China's most significant polymaths. His scientific inventions, particularly the seismoscope and armillary sphere, represent remarkable achievements in ancient Chinese technology. The seismoscope, invented in 132 CE, was the first known device for detecting earthquakes and remained unsurpassed in the West until the 19th century. His water-powered armillary sphere demonstrated advanced understanding of mechanical engineering and astronomical observation.

In literature, Zhang Heng is celebrated as one of the "Four Masters of Han Fu" alongside Sima Xiangru, Yang Xiong, and Ban Gu. His "Er Jing Fu" stands as a monumental work of descriptive literature, while his "Gui Tian Fu" is considered the first mature parallel prose piece in Chinese literature and a precursor to Tao Yuanming's famous "Gui Qu Lai Ci" (Returning Home). His "Si Chou Shi" represents an important development in the evolution of seven-character verse in Chinese poetry.

Zhang Heng's cosmological theories, particularly as expressed in "Ling Xian," reflect a sophisticated understanding of the universe that integrated traditional Chinese cosmology with empirical observation. His three-stage theory of cosmic evolution—"mingxi" (primordial chaos), "panhong" (vast chaos), and "taiyuan" (great beginning)—demonstrates his philosophical depth and influenced later Chinese cosmological thought.

Modern Status

Today, Zhang Heng is remembered as one of China's greatest scientific minds and literary figures. His inventions continue to be studied in the history of science, with particular interest in the reconstruction of his seismoscope. Modern scholars have proposed various models based on different interpretations of historical descriptions, with the suspended pendulum model gaining significant acceptance.

In popular culture, Zhang Heng has been featured in numerous documentaries, books, and museum exhibits that highlight China's scientific achievements. His life and work are often cited in discussions about the history of science and technology in China and the broader East Asian region. The crater Chang-Ngo on the far side of the Moon is named after him, as is the asteroid 1802 Zhang Heng.

In China, Zhang Heng is celebrated as a symbol of Chinese scientific excellence and intellectual achievement. His hometown in Nanyang has established memorial sites and museums dedicated to his life and work. His name is frequently invoked in educational contexts to inspire students in science and technology.

References

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2. Cullen, Christopher. (2007). Astronomy and Mathematics in Ancient China: The 'Zhou Bi Suan Jing'. Cambridge University Press.

3. Loewe, Michael, and Edward L. Shaughnessy (eds.). (1999). The Cambridge History of Ancient China: From the Origins of Civilization to 221 B.C. Cambridge University Press.

4. Nylan, Michael. (2001). The Five 'Confucian' Classics. Yale University Press.

5. Balashov, Yuri, and Alexei Grinin. (2010). Evolution: Cosmic, Biological, and Social. Uchitel Publishing House.