In warfare in civilised and highly developed countries, when the enemy's object is rather to defeat the fighting force than to harry the convoy, and when troops can march on broad frontages, the protection given by bodies of cavalry with horse artillery, flung far to front and flanks, and supported, if necessary, by infantry, is usually adequate.
But when the line of march leads along a single file track, winding through narrow valleys, and over rugged mountains, when the column, compared to its strength, occupies an inordinate length of roadway, and is therefore especially vulnerable to flank attack, and when the enemy, or at any rate a portion of his warriors, prefer plunder of baggage to pitched battles, other measures to safeguard the force must be taken.
Flankguards can rarely make their way over the steeply scarped hills enclosing the North West Frontier valleys, and since the advanced guard can, in such conditions, effect no more than the clearance of the valley in which it is moving, it becomes necessary to adopt a sedentary form of protection for the flanks of the force. This consists of picquets, posted along the route, in localities commanding approaches to the roadway, or from which the enemy can fire on the column.
These picquets, together with the advanced and rear guards, secure the movement of the remaining troops; they are, as a rule, found by the units composing the advanced guard, and withdraw under the supervision, and if necessary with the assistance of the rear guard.
The order of march of a column, in border, as in other campaigns, is conditioned by the proximity, strength, and probable action of the enemy, by the topography of the district to be traversed, by the object to be attained, and by the composition of the force.
The first duty of the staff officer to whom is confided the drafting of orders for a march, will therefore be, by personal observation, and from intelligence and other reports, to find out as much as possible of the country, and of the enemy's dispositions and probable tactics. Armed with this information he will be in a position to arrange the order of march of his column according to the circumstances of the case.
When the enemy, for instance, is in force in the vicinity, and his actions, such as throwing up of entrenchments, harassing camp in large numbers, imply that he will offer vigorous resistance to the advance, it is probable that the baggage and supply column will be best parked, under sufficient guard, either in the camp, or in some other locality easy of defence, whilst the remainder move off, in preparatory formation for action.
If the clansmen are reported to be inclined to dispute the advance in force, but are some distance from the camp, the most suitable order of march may be deduced as follows.
The enemy being in strength, the column should move in compact formation, and deliberately, the advanced guard being pushed only so far forward as to secure the troops from surprise, and as few road picquets sent out as may be, in order that the fighting force may be reduced as little as possible.
The method of posting and withdrawing picquets will not materially differ from that which will be described later.