From the second half of the seventh century Byzantine Empire established an administrative, military and economic based system, which was called theme to remove damaging effects of Anatolia the raids that the Arabs have organized every summer. With this system, the Empire protected the eastern borders with garrisons including administrative and military strategies such as bandon, kleisoura and tourma which were the subordinate administrative and military units of theme. Thus, the Empire tried both to resist the Arab attacks and to organise Anatolia as politically administratively, militarily and socio-ally. Each of these garrisons performed a task for the Empire and the most important are the kleisouras called "mountain passes" and the regions that the Byzantine-Islamic forces met for the first time. Thus, the kleisoura districts which form part of the empire's frontier defense policy are worth examining in terms of history of both Anatolia's administrative and military and Byzantine-Islamic relations. In this context it contains detailed information on the Tacticons, which was received in the Xth century and is a Military Manual. The purpose of this work is to examine the administrative, military and strategic significance of the Kleisauras in the Byzantine-Islamic struggles and founding purpose of the establishment of the kleisouras according to the Tacticons.