《资治通鉴·汉纪·汉纪六十》
关羽派兵驻扎偃城，徐晃军队到达后，通过隐秘的小径围绕偃城，掘一道长壕，表示要截断关羽守军的后路，关羽守军便烧毁营盘退走了。
关羽遣兵屯偃城，晃既到，诡道作都堑，示欲截其后，羽兵烧屯走。
Guan Yu sent troops to garrison Yancheng; after Xu Huang’s troops arrived, they took a concealed small path to surround Yancheng, dug a long moat, and indicated that they would cut off the retreat of Guan Yu’s garrison troops, so the garrison troops burnt their camp and retreated.