At this time, it was the rainy season. Although Metz was still at the front lines, with occasional shell explosions nearby, a large number of workers had already moved in to begin the construction of the "super defensive line."
The reason Metz could become the core segment of the super defensive line was because it already had large-scale ground fortresses, and tunnels connected these fortresses. With slight modifications, it could integrate them into the defensive line to form a complete system.
Shire set the main defensive line about 10 kilometers north of Metz, creating a salient towards the German Army.
This utilized Metz's characteristic of being easy to defend and hard to attack, putting the German Army in a "throwing themselves into a trap" situation.
Once the German Army broke through this defensive line and attempted to penetrate into France, they would immediately be blocked by Metz and fall into a dead end.
