The functions of the fortress were separated from the functions of the castle, thickness took precedence over height for the fortress, and star-shaped ryoho shiki (a style based on the fortification of Vauban in France) fortresses became dominant as permanent fortresses and trenches became dominant as field fortresses.
このため要塞と城の機能は分離されるようになり、要塞は高さより、厚さを重視するものになり、永久要塞としては星型(稜堡式)要塞が、野戦要塞としては塹壕が主流となった。