The Liege Fortress is indeed impregnable, but these fortresses are usually built on high ground at an altitude of 100 to 200 meters, forming a firepower strike on the plains below from above.
The advantage of this design is that it expands the defenders' field of vision and increases the artillery range, allowing the fortress's firepower to be utilized to its maximum effect.
However, the drawback is also obvious: the fortress has many blind spots in its firepower, rendering it powerless against enemies who have already charged up the high ground and surrounded the fortress.
(The above image is a plan of the Liege Fortress, with 12 fortresses forming a ring. The "Lonsin" in the red circle refers to the "Lonsin Castle" mentioned previously.)
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When formulating the battle plan, Kristen did not consider this a weakness of the fortress.
"Although what you said is true, General," Kristen said:
