An entrenchment is an obstacle that the enemy opposes to more easily and advantageously defend the terrain that one occupies.
There are entrenchments of many species:
- The most ordinary consist of moats , the earth of which is thrown to the part where the troops to be covered are located and serves as a parapet
- They are also made with trees that are felled and placed one on top of the other ( Abatida ) or with jars, stones, rubble from demolished old walls or walls , sashes, earth, etc.
- The name of entrenchment is also given to the cuts that are made in the exterior works of the squares and in the bastions to defend them step by step. These kinds of entrenchments are made up of a small wall and a parapet that ordinarily form an incoming angle to better defend the enemy from approaching: it is made with earth bags, gabions, fascines, etc.
- The name of entrenchments is also given to the bypass lines.
The arrangement of the entrenchment must be arranged according to the principles of fortification. Examine equally the strength of all points, fortify those that are naturally weaker, occupy those that nature made most advantageous; As soon as possible take a straight line, cut by large and frequent salient points, from which the prayers cross for a considerable length.
The defense consists of making all the parts or points equally strong as far as possible; reinforce the weakest with the best troops or with a greater number, with reserves, with a lot of artillery and especially with the most skillful and brave generals.
The art of the attack consists in distinguishing the weakest part of a position, directing the main forces against it, while with other sham attacks one tries to call the enemy to them or at least force him to keep the troops in their positions.
M. de Feuquiers has given some precepts on the attack of an entrenched army. Advantages can be gained, he says, against an army which, once forced to take a bad position, has fortified its field and collected from it all the food and fodder that it could and thought it needed. In this case, it is not without example that batteries were built, the trench was opened, some land very close to the enemy field was gained to place in artillery and finally, after having ruined and opened part of the entrenchments, they were attacked with strong force: but it is necessary to warn that the attacks of this kind should only be done as soon as there is room against the flanks of the field and when it can be attacked with a front greater than that of the enemy.
It should also be noted that it is good to fatigue him a few days before the attack and make him suffer some essential needs. In general, the attack of an entrenched army supposes a great superiority in the attacker and also the necessity to commit the action since in it many people will always be lost; Well, it may produce the entire ruin of the enemy army, thus forced into its own field.