Han Chang'an City: The Empire's Heart and Historical Mirror in "Zizhi Tongjian"

Brief Introduction

Chang'an, serving as the capital of the Western Han and early Eastern Han dynasties, was the first truly large-scale and rigorously planned imperial capital in Chinese history. It was not only the eastern starting point of the Silk Road but also the absolute core of the Han Dynasty's politics, economy, and culture. In the chronological universal history Zizhi Tongjian (Comprehensive Mirror in Aid of Governance), compiled by Sima Guang, Chang'an is more than a geographical name; it is a barometer of political rise and fall, embodying the core philosophy of "using history as a mirror."

Core Knowledge Points

* Geographical Location and Scale: Han Chang'an City is located in the northwest of present-day Xi'an. Its city wall perimeter measured 25 kilometers, covering an area of approximately 36 square kilometers, far exceeding the later Ming and Qing Beijing City. Its immense scale reflects the strong national power and population density of the Han Dynasty.
Urban Layout and Function: The city implemented a prototype of the strict Lifang* (ward) system and established nine markets. Among them, the East Market and West Market were the commercial cores, gathering merchants from all nations along the Silk Road. The Weiyang Palace and Changle Palace were the centers of imperial power; the ruins of the Weiyang Palace Front Hall remain visible today, witnessing the prosperity of Emperor Wu's reign.
* Historical Status: Chang'an was one of the largest cities in the world at the time and an important hub for exchange between Eastern and Western civilizations. It established the basic paradigm for future capital planning and exerted a profound influence on East Asian urban culture.

Connection with "Zizhi Tongjian" Content

In Zizhi Tongjian, records of Chang'an span from the Western Han to the early Eastern Han. Sima Guang elaborates on governance concepts through the order and chaos of Chang'an:
1. Witness to Prosperity: The book details the restorative policies and territorial expansion after Emperor Wu of Han established the capital in Chang'an. Chang'an became the decision-making center, symbolizing the dynasty's zenith. Sima Guang used this to affirm the political strategy of "strengthening the trunk and weakening the branches" (centralizing power).
2. Microcosm of Turmoil: It records the chaos in Chang'an during Wang Mang's usurpation of the Han and the tragedy of Dong Zhuo burning Chang'an at the end of the Eastern Han. In his commentary sections ("Chen Guang Yue"), Sima Guang used these events to warn future generations of the importance of vigilance in times of peace, pointing out that the security of the capital concerns the fate of the nation.
3. Turning Point of Capital Relocation: The book records Emperor Guangwu of Han (Liu Xiu) establishing the capital in Luoyang, marking a decline in Chang'an's status. This signifies a historical turning point where the political center shifted eastward, reflecting changes in geopolitics and the impact of warlord separatism.

Summary

Han Chang'an City was not merely a city constructed of bricks and stones, but an important carrier of historical lessons within Zizhi Tongjian. Its rise and fall provided valuable references for governance to later generations, serving as a key to understanding Han history and the evolution of Chinese civilization. For modern readers, combining the reading of Chang'an's history with Zizhi Tongjian allows for a deeper insight into the intrinsic logic between the succession of power and the fate of cities.