Houchengzui Stone City Reveals 4300-Year-Old Triple Defence System

January 14, 2024: Archaeologists in Inner Mongolia, China, have unveiled a remarkable archaeological treasure – the ancient Houchengzui Stone City, estimated to be around 4,300 to 4,500 years old. This sprawling site, covering half a square mile, stands as the largest and most heavily fortified archaeological marvel in Inner Mongolia from the early Longshan period (3000 to 1900 BC).

The ongoing excavation, initiated in 2005 and led by the Institute of Archaeology, Chinese Academy of Social Sciences (CASS), has unearthed a sophisticated triple-defence system and an intricate network of tunnels. This recent revelation sheds light on the city’s strategic design, emphasizing its cultural significance in military defence during the ancient Longshan period.

The triple-defence system includes the main city wall, terraces, gatehouse walls, moats, and trenches. The ongoing exploration has brought forth a new layer of defence – a complex tunnel system beneath the city. Believed to serve dual purposes, these ancient tunnels functioned both as a transportation network and a means of defence and offence.

Measuring 3-6 ft in height and approximately 4 ft in width, the tunnels boast arched ceilings reminiscent of Longshan period cave dwellings. These tunnels, arranged in a radial pattern, connect to the center of the subterranean city, passing under the fortified city walls and extending beyond its boundaries. Some passages open from outside the city, traversing various structures like the outer Wengcheng city wall, trenches, and the Wengcheng square.


The strategic significance of Houchengzui Stone City is evident in its elaborate defence systems and concealed tunnels, highlighting its role as a crucial strategic location during ancient times.

The stone city itself consists of an inner and outer city fortified with three concentric walls, guarded gates, and trenches. Recent excavations from 2019 to 2023 focused on the Wangcheng gate, high-level buildings in the inner city, and the tomb area. Researchers categorized the city’s architecture into simple and complex stone masonry and earthen walls, revealing various elements like city walls, gates, horse faces, trenches, platform foundations, underground passages, house sites, and tombs.

Among the notable discoveries are the main city gate (CM1), urn city gate (CM2), and outer urn city gate (CM3), each showcasing intricate features and architectural elements. The ongoing exploration of Houchengzui Stone City continues to provide invaluable insights into ancient civilization, military strategy, and architectural prowess during the Longshan period, unraveling the mysteries of this ancient marvel.