Objective  Hami region is a significant oasis distribution area in north-eastern Xinjiang, and is home to most of the extant military architectural heritage of the Great Wall in Xinjiang. The combination of valuable oasis resources and strategic military location makes Hami region a major transportation route extending from the inland area to the Western Regions, an important town along the northern Silk Road, and a key military defense area concerned by emperors of all generations. The purpose of this research is two fold. Firstly, the research aims to investigate whether the oasis resources in the region have any influence on the composition of the military defense system of the Great Wall and the construction of individual buildings, and the specific manifestations of such influence. Secondly, in previous researches, the military defense system of the Great Wall is typically classified into such categories as the beacon signaling system and the postal delivery system, while this research attempts to investigate the natural environment as an entry point to establish a new classification model connecting oasis and the military defense system.

Methods  Firstly, a fundamental study is conducted on the natural geographical features of the Hami region. Considering the variations in geographic position, elevation, climate traits, precipitation distribution, vegetation cover, and other natural factors, the region can be classed into three geographic zones: the Hami Basin, the Barkun Basin, and the Santang Lake Basin. Subsequently, each distinct natural feature within the different zones is meticulously analyzed, relevant data retrieved, and emphasis is placed on the analysis of the distribution, reasons for formation, and morphology of oasis in the region. Secondly, a field survey of the natural environment and architectural heritage of the Hami region is carried out to collect information and photographs. This information is then used to create a distribution map of military architectural heritage of the Great Wall in the region. These heritages are preliminarily categorized and studied by age and building type. In the third step, the planar and spatial relationships between the military architecture of the Great Wall and the oasis environment are simulated using ArcGIS software and aided to present complex spatial information intuitively. The inferred conclusions are verified with historical documents, and the different types of military defence systems in the region are summarized from a macro perspective. Lastly, based on the field surveys, the materials and structures of the military buildings of the Great Wall in different environments are examined from a micro perspective. The geographic distribution of the construction methods are then mapped to explore the relationship between the building constructions, oasis, and natural environments.

Results  The military defense system and construction of military architecture along the Great Wall in the Hami region rely heavily on the oasis resources present. These resources serve as the foundation for sustaining military structures, while also playing a crucial role in the composition of defense system of the Great Wall and the construction of the military buildings in Hami. Differences in the overall morphology and spatial distribution of the oasis influence the macro-defense system and micro-architectural construction. Key factors which influence this include: 1) Oasis resources provide the basis and decision-making ideas for top-level macro-defense of the military defense system. During construction, the distinct forms of oases and environmental features were used to create natural barriers, such as mountains and lakes, coupled with artificial defenses like beacons, posts, and garrisons, constructing multiple lines of defense. 2) When building military structures, oasis resources provided craftsmen with low-cost and convenient materials, reflecting the region’s distinct characteristics. Therefore, military buildings along the Great Wall in the Hami area were constructed using locally made materials, adapting to the land’s conditions and locating sites close to water sources with unobstructed lines of sight. This resulted in a mountainous defense line regulated by dot-shaped oasis (distributed in the northeastern part of Barkol Basin), a watery defense line regulated by surface-shaped oasis (distributed in the western part of Barkol Basin), and a plains defense line regulated by belt-shaped oasis (distributed in the Hami Basin). These defense lines served both as a means of military defense and as protection for the Silk Road traffic. Strengthening the rule of the Central Plains on the western frontier, military structures in the Hami region played dual roles as defense and protection for the oasis.

Conclusion  Oasis resources are a significant driving force and influencing factor in the construction of military buildings of the Great Wall in the arid northwest region in China. The relationship between the oasis resources and the Great Wall heritage can be described as mutual promotion and interaction. This research considers the relationship between architecture and environment from the perspective of oasis, placing the Great Wall heritage in the context of the entire natural geography. This research categorizes and studies the Great Wall defense system and the Great Wall monolithic architecture by a new method, hoping to provide new ideas for future Great Wall research, while raising public awareness of the military heritage of the Great Wall, and of the siting and construction wisdom and and value connotations of such heritage.