On the other hand, due to military necessity and also for the necessity of warring loads strengthening the control of their territories, 'tenshu' (also tenshukaku: castle turret) was designed based on boroes, with many such turrets built as a symbol of castle buildings.
一方、軍事的必要性、及び戦国大名の一円支配強化から望楼を起源とする「天守」（天守閣）が現れ、城郭建築の象徴として一世を風靡することとなる。