When a march is made to force a pass guarded by the enemy, it is desirable to make a feint upon one point, while, by a rapid movement, you bring your real attack to bear upon another.
Sometimes success is obtained by pretending to fall back upon the original line of march, and, by a sudden countermarch, seizing upon the pass, before the enemy is able to reoccupy it. Some generals have gained their point by manœuvring so as to deceive the enemy, while a detachment under the cover of high grounds has surprised the passage by a stolen march. The enemy being engaged in watching the movements of the main body, the detachment has an opportunity of entrenching itself in its new position.
5. An army regulates its mode of encampment according to the greater or less degree of precaution, when circumstances require. In a friendly country the troops are divided, to afford better accommodation and supplies. But with the enemy in front, an army should always encamp in order of battle. With this view, it is of the highest importance to cover one part of the camp, as far as practicable, by natural defences, such as a river, a chain of rocks, or a ravine. Care should be taken also that the camp is not commanded, and that there is no obstacle to a free communication between the different corps, and which can prevent the troops from mutually succoring each other.
When an army occupies a fixed camp, it is necessary to be well supplied with provisions and ammunition, or at least that these should be within certain reach and easily obtained. To insure this, the line of communication must be well established, and care taken not to leave an enemy’s fortress in your rear.
When an army is established in winter quarters, its safety is best secured either by fortifying a camp (for which purpose a spot should be selected near a large commercial town, or a river affording facility of transport), or by distributing it in close cantonments, so that the troops should be near together, and capable of affording each other mutual support.
The winter quarters of an army should be protected, likewise, by constructing small covered works on all the lines of approach to the cantonments, and by posting advanced guards of cavalry to observe the motions of the enemy.
6. A battle is to be sought, when there is reason to hope for victory, or when an army runs the risk of being ruined without fighting; also when a besieged place is to be relieved, or when you desire to prevent a reinforcement from reaching the enemy. Battles are useful, likewise, when we wish to profit by a favorable opportunity which offers, to secure a certain advantage, such as seizing upon an undefended point or pass, attacking the enemy when he has committed a fault, or when some misunderstanding among his generals favors the undertaking.
If an enemy declines an engagement, he may be compelled to it, either by besieging a place of importance, or by falling upon him unawares, and when he cannot easily effect his retreat. Or (after pretending to retire), by making a rapid countermarch, attacking him vigorously and forcing him to action.
The different circumstances under which a battle should be avoided or declined, are, when there is greater danger to be apprehended from defeat than advantage to be derived from victory; when you are very inferior to your adversary in numbers, and are expecting reinforcements; above all, when the enemy is advantageously posted, or when he is contributing to his own ruin by some inherent defect in his position, or by the errors and divisions of his generals.