In addition, since in theory the defensive line only had to hold out long enough for mobile reserves to reinforce it, terrain that did not permit rapid advance could be held more weakly because the enemy's advance into it would be slower, giving the defenders more time to reinforce that point in the line.
Štoviše, budući da u teoriji obrambena linija samo mora izdržati dovoljno dugo dok ne stignu pojačanja mobilnih rezervi, teren koji nije dopuštao brzi napredak mogao se držati sa slabijim snagama jer bi neprijateljski napredak u njemu bio sporiji, dajući braniteljima dovoljno vremena da pojačaju tu točku na liniji.