Wubei Zhi (Vol. 49) (1621) - Page 22

Treatise on Armament Technology, Volume 203
Defense: Fortification Regulations
Page Eleven

Two sides of a large fort

form one terrace

Illustration of a Large Fort Bastion

The diagram on this page illustrates a Large Fort original: 大堡 dabao being utilized as a foundational unit for a Terrace original: 臺 tai; often referring to the ditai or "Enemy Terrace". In the context of the *Wubei Zhi* (Treatise on Armament Technology), these terraces were not merely platforms but fortified towers that projected out from the main wall to provide flanking fire. While smaller forts required three sides of their structure to form an effective projecting bastion, the larger scale of the "Large Fort" meant that incorporating just two sides into the defensive line provided sufficient projection and internal space for troops and equipment. The woodcut illustration depicts a square plan with crenellated battlements—the "notched" walls designed to protect defenders while they fired upon attackers. This specific design was part of the sophisticated defensive network championed by Ming generals like Qi Jiguang to defend the northern frontiers against cavalry incursions.