Fortress walls with usable intra-wall space in Bactrian fortifications

Taking the Uzundara fortress as a case study, the paper reviews a specific element of fortification, which is fortress walls with usable intra-wall space. The analysis of technical design of the construction helps clarify some terms used in literature to describe this type of fortifications. It is proposed to single out monolithic walls and walls with intra-wall usable space. Multiple analogies in Bactrian architecture and neighboring historical and cultural regions reiterate special similarity of fortifications in Bactria and Khwarazm. The review of dozens of sites with the use of double walls chronologically throughout the Classical period requires changes to be made in the established opinion that in the Hellenic period the shift to monolithic walls occurred across the board. The use of fortress walls with intra-wall usable space in fortifications and Hellenistic and Kushan fortresses suggests that they were constructed, when necessary and when possible, depending on multiple factors