STRATEGY (from the Greek serparrsyfa, which may be translated " generalship ") is, properly, the science of combining and employing the means which the different branches of the art of war afford for the purpose of forming projects of operations and of directing great military movements: it was formerly distinguished from the art of making dispositions, and of inauceuvring, when in the presence of the enemy ; but military writers now, in general, comprehend all these subjects under the terms of grand and elementary tactics. [TACTICS.) The general principles of strategy and tactics have been and must be the same in all ages. To overcome the enemy, it is necessary to be superior to him at the point of collision, not necessarily numerically, for number only does not always represent the strength or relative strength of an army, but superior when due allowance is made for other advantages or disadvantages. The object then of all strategical combinations should be to bring the mass of the forces in collision with fractions of the enemy ; and secondly, to act as much as possible on his communications or lines of operations without exposing one's OWIL The roads on which an army, or portion of an army, marches, are termed strategical lines, and the belt of ground containing two or more strategical lines, if lying close together, is termed a line of operations. In order then to bring, and always to have the power of bringing, the mass of the forces in collision with fractions of the enemy, it is neces sary to choose such lines of operations as are interior ; interior, that is, with respect to those on which the enemy acts. That is to say, that these lines must be, relatively to those of the enemy, such that the portions of the army moving on them may be more easily or rapidly united than the enemy can be, moving on his, so as to be superior at any particular point to the enemy. As a general rule, then, disregarding the relative rates of marching of armies, cross roads, &c., interior lines are such as are closer together.
Strategy consists, therefore, chiefly in making choice of convenient bases (fortified places or strong positions) in order to place there in security the military establishments of an army ; such as the barracks, hospitals, and magazines of ammunition and provisions, previously to commencing offensive operations, or in contemplation of the army being compelled to act on the defensive. In the former case, it may be necessary to decide on undertaking the siege of some fortress on a frontier, should there be none such in possession, for the purpose of holding the neighbouring district in subjection, and commanding the roads by which it may be thought convenient to penetrate into the enemy's country, or by which the provisions and warlike stores may be brought up to the immediate seat of the war. In the latter case, choice is to be made of positions strong by nature, or which may be made so by art, for the army to retire to while disputing the ground gradually, harassing the enemy by frequent skirmishes, or preventing him from receiving supplies by intercepting his convoys on the roads.
Thus, after the battle of Vittoria (1813) the allied British and Spanish armies being at a great distance from the original base of operations in Portugal, and it being intended to carry the war into France, Lord Wellington undertook to besiege St. Sebastian and to blockade I'ampeluna, in order, by the possession of those places, to have secure stations for his recruits and magazines while the army advanced into the mountainous districts between St. Jean I'ied-de-Port and the sea. On the other hand, the conviction, in 1809, that the British army would be compelled to act entirely on the defensive, induced the English general to take measures for a retreat into Por tugal, and to commence, many months before the retreat took place, two chains of strong redouts on the north of Lisbon, in the expecta tion of being able there to resist effectually the very superior forces of the enemy.