External defensive constructions of Jurchen cites in Eastern Xia

The Eastern Xia Kingdom (1215-1233) was established by the Jurchens to defend themselves against invasions of the Mongols in North-East China that included the southern parts of the Far East of Russia. Local topographic features were widely used in construction of city fortresses. Mountain landscape provided an opportunity to build mountainous fortified settlements into narrow valleys of sopkas to follow the natural terrain contours and use them to create additional obstacles. Excavations of the Shayginskoye hillfort revealed main and additional defensive constructions of Jurchen fortified settlements tracing the evolution of medieval defensive architecture in the Far East. Additional external constructions such as redans and cut-off ramparts were erected in soft spots of fortifications. The redan of the Shayginskoye hillfort was a construction around 20 m wide which was surrounded with three ramparts and three ditches. Cut-off ditches that closed access to the hillfort through promontories were used as an additional obstacle. Four cut-off ditches were identified at the Shayginskoye hillfort. External fortification constructions such as redans and cut-off ditches served to be the first defensive line of Jurchen fortress cities. This type of fortifications was recorded for the first time in mountainous hillforts of Eastern Xia. They can be regarded as an achievement of Jurchen town planners of the 13th century.