Tactics, MILITARY, the science which enables one of two opposing bodies of troops to be stronger than the other at every crisis of an engagement. This may be due to superior numbers, favourable ground, better arms, a higher state of discipline and training, or anything else that, if used to the best advantage, will produce greater strength at the point where and time when it is most essential.
Strategy (q.v.), which has precisely the same objects, merges into tactics as the enemy comes within striking distance, and the latter science is therefore sometimes defined as the strategy of the battlefield. Modern writers use different terms for the various branches of tactical science: grand tactics and manœuvre tactics, for the marshalling of large masses (30,000 and upwards) of men on the battlefield; minor tactics, for the conduct of small bodies, such as advanced and rear guards, outposts, patrols, &c.; fighting tactics, for the combat whatever the numbers of the force; fire tactics, for the best use of guns and rifles, the massing of their fire, and the selection of the target; and the special tactics of cavalry, artillery, or infantry, combined tactics, siege tactics, and mining tactics.
It would be impossible to enumerate all the schemes and devices which go to make up this science, varying as they must with the arms in use and the manœuvring power of the troops employed, but some illustrations may be given from ancient and modern history. In Judges xx. we read of a favourite and dangerous manœuvre, the Israelites feigning to retreat before the Benjamites, so as to draw them on until their flanks and rear were exposed to the 'liers in wait.' Hannibal at Cannæ and William the Conqueror at Hastings were among the many successful imitators of these tactics. Others, like the Duke of Burgundy in 1476 at Granson, lost their armies through attempting it with unsteady troops. Frederick the Great owed his victory at Mollwitz to the rapid fire and steady discipline of his men, and the former was chiefly due to the introduction of iron rammrods. His later battles give us good examples of manœuvre tactics. At Leuthen he engaged the Austrians, immovable in their chosen position, with his advanced guard, while his main body, under cover of some hills and foggy weather, marched in open column of companies round their flank, wheeled into line, and rolled up their army. At Rossbach he showed how to defeat this manœuvre when the enemy put it in practice. Sending his cavalry and artillery to check the head of their marching columns, he threw his main body upon their flank and inflicted a crushing defeat. At Kolin his linear tactics failed because the rear of his column wheeled into line too soon, leaving the head to continue the march, so creating a wide gap in the line when formed up. At Waterloo Napoleon showed an example of combined tactics on a large scale. By cavalry charges he obliged the British infantry to form squares, which then became targets for his massed artillery. When under stress of this 'hard pounding' they opened out into line, a renewed charge of cavalry obliged them to take the denser formation again. At Gravelotte the German armies (some 240,000 men) showed an unparalleled instance of grand tactics by marching to their positions across country in seven large masses, each consisting of one complete army corps. The minor tactics employed by advanced or rear guards and outposts are to a certain extent stereotyped. Their object is to prevent the main body—in the first case a column, often several miles long; in the second a large camp, cantonment, or bivouac—from being attacked before it can get into fighting order. Therefore a series of small parties of two to six men lead the way, or stand sentry, some four miles in front of the main body, while larger bodies support them at a little distance, followed in their turn by still larger units, so that the enemy meets with an ever-increasing resistance until he finds himself confronted by the main body drawn up in a carefully chosen position. Fighting tactics must depend chiefly upon the arms in use. The mail-clad horsemen of the 15th century never succeeded in defeating the solid phalanx of pikemen opposed to them by the Swiss Confederation until the employment of artillery prevented the latter retaining such a massive formation. The English archer, protected in front by palisades and on the flanks by spearmen, destroyed the chivalry of France at Cressy and Poitiers, but at Bannockburn was ridden down by the Scottish cavalry, because the flanking spearmen had been omitted. Gustavus Adolphus, by employing cartridges, enabled his infantry to fire more quickly than his opponent and so to form on a wider front. The invention of the bayonet, doing away with the necessity for pikemen to protect the musketeers, still further increased the fire-power of infantry. The British two-deep line overthrew, by its enveloping fire and charge, the column formation of the French in the Peninsula and of the Russians at the Alma, though in this battle its defects are shown in the confusion caused by moving to the attack over broken ground. In the battles of the Franco-German war of 1870-71 it was found impossible to advance against the fire of modern breech-loading rifles except by rushes of comparatively thin lines of skirmishers, constantly reinforced by supports and reserves in rear. The magazine rifle and smokeless powder of to-day still further complicate the problem, presented to the assailant, of how to get to within 500 yards of the enemy without being destroyed. No rules can be laid down except that the attacker's first line must move in three portions, skirmishers, supports, and reserves, followed by a second line to assist in the assault, and a third to complete the success or cover a retreat.
In warfare against savages large numbers, fanatical courage, and rapid movements have to be met by special tactics. Thus the crescent-shaped enveloping attack of the Zulus and the rapid attacks of the Soudanese Arabs were received in the impenetrable square formation or by forming 'laagers': a reproduction of the wagon tactics by which the Hussites of Bohemia defeated the German cavalry in the 15th century, opposing a material obstacle to the onslaught of an enemy unprovided with artillery.
Cavalry tactics, apart from the exceptional use of dismounted men, are much the same as in the time of the Byzantine empire. Cavalry fight by shock action only, and the power of man and horse has not altered. The Byzantine Turma, like the British cavalry brigade, attacked in two lines, with a reserve, flanking parties, and reconnoitring groups, manœuvring in column and attacking in line. Artillery tactics consist in massing the fire of every gun as soon as possible upon important points, and overwhelming the enemy's guns and infantry with projectiles at ranges of two miles or more, not shunning closer quarters if the necessity arises.
Siege tactics belong to fortification, but follow the same general course as other combined tactics. Thus in defence the guns oblige early deployment and co-operate with the infantry in repelling the advance, while in the attack they destroy the material defences and keep down the fire of the place so as to enable the assault to be delivered. During the siege mining tactics (see MINES, MILITARY) will be made use of on both sides. The functions of the cavalry are first to try to drive off the enemy's cavalry and effect reconnaissances on both sides; then on the attacker's side to complete the investment, and afterwards secure the besieging troops against surprise.