Thus considered, the principles of tactics look simple enough. However, it is one thing to analyze tactics in the abstract but entirely another thing to put theory into practice under different circumstances, on different kinds of terrain, against different kinds of enemy, with the aid of troops who may be tired or confused or recalcitrant, and amid every kind of mortal danger. As the great Prussian general Carl von Clausewitz said, “In war everything is simple, but even the simplest thing is difficult.” Sophisticated tactics require well-trained, articulated forces consisting of different units that are armed with different weapons and possess different capabilities. Next, these units must be subordinated to a single directing brain and must be employed in a coordinated manner following a single, well-considered plan: hence the principle of unity of command.

Even then, tactics are not just a question of executing a plan, however clever and well conceived. In tactics, even more than elsewhere, a commander who can only make a plan and carry it out avails nothing; inasmuch as he is confronting a living enemy, what matters is his ability to adapt the plan to that enemy’s reactions rapidly, smoothly, and without losing his grip. Flexibility is thus a cardinal principle of tactics. But flexibility will prevail only if it can be bound by a firm disciplinary framework. Moreover, flexibility and discipline are not easy to combine and can often be achieved only at each other’s expense. Other things being equal, the larger and more powerful a given force, the less flexible it will be.

As an armed force exchanges blows with an enemy, adapting to his moves and forcing him to adapt in return, opportunities to take him by surprise should present themselves. Surprise presupposes secrecy, but secrecy may be hard to combine with the rapid action that is often necessary for implementing surprise. Like everything else in tactics, overcoming this paradox is a matter of striking a balance, first in general and then against a specific enemy, under specific circumstances and with a specific objective in mind.

The importance of terrain

Finally, in tactics (as in strategy) there is the topographical element to consider. Land warfare is fought neither in a vacuum nor on a uniformly checkered board. Instead, it unfolds over concrete terrain, including roads, passages, elevated ground, cover, and obstacles of every kind. Victory goes to him who best understands and utilizes the terrain; this may be done by, for example, occupying dominant ground, utilizing cover, compelling the enemy to fight on terrain for which his forces are not suitable, cornering him, outflanking him, or surrounding him. All these methods are as old as warfare, yet at the same time they remain relevant to the present age. On their correct application the outcome of battle depends.

Historical development

Tribal and ancient tactics

The ambush and the trial of strength

The oldest, most primitive field tactics are those that rely on concealment and surprise—i.e., the ambush and the raid. Such tactics, which are closely connected to those used in hunting and may indeed have originated in the latter, are well known to tribal societies all over the world. Typically the operation gets under way when warriors, having reconnoitred the terrain and stalked their enemy, take up concealed positions and wait for the signal. The engagement opens by means of such long-range missile weapons as the javelin, the bow, the sling, and the tomahawk. Once the enemy has been thrown into disorder and some of his personnel killed or wounded, cover is discarded, and short-range weapons such as club, spear, and dagger are employed for delivering the coup de grace. Since concealment is vital and there is no sophisticated logistic apparatus, the number of combatants is usually no more than a few dozen or, at the very most, a few hundred. Tactical units are unknown and command arrangements, to the extent that they exist at all, elementary. None of this, however, is to say that such tactics are simpleminded. On the contrary, making the best use of difficult terrain such as mountains, forests, or swamps usually requires much skill and presupposes an intimate familiarity with the surroundings.

Apart from ambush and raid, which depend on making the best possible use of terrain, many primitive tribes also engage in formal, one-to-one frontal encounters that are part battle, part sport. The weapons employed on such occasions usually consist of the club (or its more advanced form, the mace), spear, and javelin, sometimes joined by the bow and special blunted arrows. Defensive armour consists of nonmetallic body cover of wood, leather, or wickerwork, often made in fantastic forms and painted extravagant colours in order to enlist the aid of spirits and terrify the opponent. Such fights differ from those described above in that the warriors stand in full view of each other across specially selected level terrain, the objective being to please the spectators and gather glory for themselves. However, here too there can be no question either of formations or of a command system. Rather, each man picks his opponent and fights separately. Hence, it is impossible to speak of tactics, except in the limited sense of the skill displayed by individual warriors in handling their weapons.

The phalanx

To judge from numerous descriptions in Homer, archaic Greek warriors still acted in this way. The heroes on each side knew each other by reputation and sought each other out, forming pairs and fighting hand-to-hand without any regard for either collective action or the discipline and organization that were needed for it. However, the Iliad also contains passages that may indicate a more advanced form of tactics—namely, the phalanx. Phalanx tactics are known from ancient Sumer and Egypt as well as from Greece. Their essence consisted of packing troops together in dense, massive blocks, to some extent sacrificing flexibility, mobility, and the possibility of concealment in order to achieve mutual protection and maximize striking power. In Greek armies the usual number of ranks was 8, but formations 16 and even 50 deep are recorded. Insofar as they relied on brute force, such tactics were often considered primitive even in their own day—for example, by the Persian commander Mardonius in describing them to his master, Xerxes I. For a phalanx to execute even a simple lateral evasive move, the troops had to be “professors of war”; such was the Roman historian Plutarch’s expression in describing the disaster suffered by Sparta at the Battle of Leuctra in 371 bc. As Sumerian reliefs, Egyptian wooden models, and Greek narratives show, the typical weapons employed by the phalanx were consistently short-range, hand-held instruments such as sword, spear, and pike, used in accordance to whether individual duels or mass action was considered more important. These weapons were invariably combined with defensive gear such as helmets, corselets, shields, and greaves, although here too the amount of protection varied from one case to the next (see photograph).